Revision as of 05:14, 30 June 2018

Text

Palo Verde, Units 1, 2, and 3 - Application to Revise Technical Specifications to Adopt TSTF-523, Generic Letter 2008-01, Managing Gas Accumulation, Using the Consolidated Line Item Improvement Process
	ML16182A171
Person / Time
Site:	Palo Verde
Issue date:	06/29/2016
From:	Lacal M L; Arizona Public Service Co
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	102-07285-MLL/TNW, GL-2008-01
	Download: ML16182A171 (50)
	v • d • e

10 CFR 50.90

A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway Diablo Canyon Palo Verde Wolf Creek MARIA L. LACAL Senior Vice President, Nuclear Regulatory & Oversight Palo Verde Nuclear Generating Station P.O. Box 52034 Phoenix, AZ 85072 Mail Station 7605 Tel 623.393.6491 102-07285-MLL/TNW June 29, 2016 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

-0001

Dear Sirs:

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Units 1, 2, and 3 Docket Nos. STN 50

-528, 50-529, and 50-530 Renewed Operating License Nos. NPF

-41, NPF-51, NPF-74 Application to Revise Technical Specifications to Adopt TSTF-523, Generic Letter 2008-01, Managing Gas Accumulation

, using the Consolidated Line Item Improvement Process In accordance with the provisions of Section 50.90 of Title 10 of the Code of Federal Regulations (10 CFR), Arizona Public Service Company (APS) is submitting a License Amendment Request (LAR) to revise the Technical Specifications (TS) for Palo Verde Nuclear Generating Station (PVNGS) Units 1, 2, and 3.

The proposed amendment would modify TS requirements to address Generic Letter 2008

-01, Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems

, as described in TSTF

-523, Revision 2, Generic Letter 2008

-01, Managing Gas Accumulation

.

The proposed amendment satisfies the commitment made to the NRC in APS letter number 102-05910, dated October 14, 2008 [Agency Document Access and Management System (ADAMS) accession number ML082940032], as modified by letter number 102-06982, dated December 30, 2014 (ADAMS accession number ML15005A386

). The enclosure to this letter provides a description and assessment of the proposed changes including a summary of the technical evaluation, a regulatory evaluation

, a no significant hazards consideration, and an environmental evaluation

. Additionally, the enclosure contains three attachments

. Attachment 1 provides the marked-up existing TS pages. Attachment 2 provides the revised (clean) TS pages. Attachment 3 provides the marked-up TS Bases pages to show the conforming changes.

102-07285-MLL/TNW ATTN: Document Control Desk U. S. Nuclear Regulatory Commission LAR to Revise TS Regarding Managing Gas Accumulation Page 2 In accordance with the PVNGS Quality Assurance Program, the Plant Review Board and the Offsite Safety Review Committee have reviewed and approved the LAR. By copy of this letter, this LAR is being forwarded to the Arizona Radiation Regulatory Agency in accordance with 10 CFR 50.91(b)(1).

APS requests approval of the LAR within one year from the date of the submittal and will implement the TS amendment within one year following NRC approval.

No new commitments are made by this letter. Should you have any questions concerning the content of this letter, please contact Michael DiLorenzo, Licensing Section Leader, at (623) 393-3495.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on : June 29, 2016 (Date)

Sincerely,

MLL/TNW/CJS/af

Enclosure:

Description and Assessment of Proposed Amendment to Implement TSTF 523 cc: K. M. Kennedy NRC Region IV Regional Administrator S. P. Lingam NRC NRR Project Manager for PVNGS M. M. Watford NRC NRR Project Manager C. A. Peabody NRC Senior Resident Inspector for PVNGS A. V. Godwin Arizona Radiation Regulatory Agency (ARRA) T. Morales Arizona Radiation Regulatory Agency (ARRA)

Enclosure Description and Assessment of Proposed Amendment to Implement TSTF 523 i TABLE OF CONTENTS 1.0 SUMMARY DESCRIPTION----------------------1 2.0 ASSESSMENT---------...-----------------..1 3.0 REGULATORY ANALYSIS----------------------.2 4.0 ENVIRONMENTAL EVALUATION-------------------3 ATTACHMENTS Attachment 1

- Marked-up Technical Specifications Pages Attachment 2

- Revised Technical Specifications Pages (Clean Copy)

Attachment 3

- Marked-up Technical Specification Bases Pages

Enclosure Description and Assessment of Proposed Amendment to Implement TSTF 523 1 1.0 SUMMARY DESCRIPTION

The proposed change revises or adds Surveillance Requirements to verify that the Safety Injection (SI) [Emergency Core Cooling System (ECCS), Shutdown Cooling (SDC) and Containment Spray (CS)

] system locations susceptible to gas accumulation are sufficiently filled with water and to provide allowances which permit performance of the verification. The changes are being made to address the concerns discussed in Generic Letter 2008

-01, Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems. The proposed amendment is consistent with TSTF

-523, Revision 2, Generic Letter 2008

-01, Managing Gas Accumulation. The availability of this Technical Specification (TS) improvement was published in the Federal Register on January 15, 2014

, as part of the consolidated line item improvement process (CLIIP).

2.0 ASSESSMENT

2.1 Applicability of Published Safety Evaluation Arizona Public Service Company (APS) has reviewed the model safety evaluation dated December 23, 2013

, as part of the Federal Register Notice of Availability. This review included a review of NRC staff's evaluation, as well as the information provided in TSTF

-523. As described in the subsequent paragraphs, APS has concluded that the justifications presented in the TSTF

-523 proposal and the model safety evaluation prepared by the NRC staff are applicable to Palo Verde Nuclear Generating Station (PVNGS)

, Units 1, 2, 3 and justify this amendment for the incorporation of the changes into the PVNGS TS. 2.2 Optional Changes and Variations PVNGS TS utilize different numbering than the Standard Technical Specification s (STS) on which TSTF-523 was based. In the cases listed below the STS Section number corresponds to a different plant TS Section number.

~ Combustion Engineering (CE) STS Section 3.5.2

, ECCS - Operating

, corresponds to PVNGS, Unit 1, 2 and 3 TS Section 3.5.3, ECCS - Operating

~ CE STS Section 3.6.6A, Containment Spray and Cooling Systems

, corresponds to PVNGS, Unit 1, 2 and 3 TS Section 3.6.6, Containment Spray System APS is proposing the following variation from the TS changes described in TSTF

-523, Revision 2: ~ Add NOTE to SR 3.4.7.4:

Not required to be performed until 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months after entering MODE 4 The addition of the NOTE to TS Surveillance Requirement (SR) 3.4.7.4 is needed since the transition from MODE 4 to Reactor Coolant System (RCS) Loops - MODE 5, Loops Filled can be accomplished within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months after entry into MODE 4. Allowing a duration of 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months to perform the surveillance after entering MODE 4 is not being changed.

The applicability of the NOTE is being extended to include RCS Loops

- MODE 5, Loops Filled sin ce the plant could be in that con dition within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months .

This variance does not impact the requirement for the Enclosure Description and Assessment of Proposed Amendment to Implement TSTF 523 2 surveillance requirement to be met in the various modes of applicability but rather it is allowing sufficient and necessary flexibility to perform the surveillance

. 3.0 REGULATORY ANALYSIS

3.1 No Significant Hazards Consideration Determination Arizona Public Service Company (APS) requests adoption of TSTF

-523, Rev. 2, Generic Letter 2008-01, Managing Gas Accumulation, which is an approved change to the standard technical specifications (STS), into the PVNGS technical specifications. The proposed change revises or adds Surveillance Requirement (s) (SRs) to verify that the Safety Injection (SI) [Emergency Core Cooling System (ECCS), Shutdown Cooling (SDC) and Containment Spray (CS)

] system locations susceptible to gas accumulation are sufficiently filled with water and to provide allowances which permit performance of the verification.

APS has evaluated whether the proposed License Amendment Request constitutes a significant hazards consideration by focusing on the three standards set forth in 10 CFR 50.92, Issuance of amendment

, as discussed below:

1. Does the proposed amendment involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No.

The proposed change revises or adds SRs that require verification that the ECCS, the SDC System, and the CS System, are not rendered inoperable due to accumulated gas and to provide allowances which permit performance of the revised verification. Gas accumulation in the subject systems is not an initiator of any accident previously evaluated. As a result, the probability of any accident previously evaluated is not significantly increased. The proposed SRs ensure that the subject systems continue to be capable of performing their safety function s and are not rendered inoperable due to gas accumulation. Thus, the consequences of any accident previously evaluated are not significantly increased.

Therefore, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

2. Does the proposed amendment create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No.

The proposed change revises or adds SRs that require verification that the ECCS, the SDC System, and the CS System are not rendered inoperable due to accumulated gas and to provide allowances which permit performance of the revised verification. The proposed change does not involve a physical alteration of the plant (i.e., no new or different type of equipment will be installed) or a change in the methods governing normal plant operation. In addition, the proposed change does not impose any new or different requirements that could initiate an accident. The proposed change does not alter assumptions made in the safety analysis and is consistent with the safety analysis assumptions.

Enclosure Description and Assessment of Proposed Amendment to Implement TSTF 523 3 Therefore, the proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.

3. Does the proposed amendment involve a significant reduction in a margin of safety?

Response: No.

The proposed change revises or adds SRs that require verification that the ECCS, the SDC System, and the CS System are not rendered inoperable due to accumulated gas and to provide allowances which permit performance of the revised verification. The proposed change adds new requirements to manage gas accumulation in order to ensure the subject systems are capable of performing their assumed safety functions. The proposed SRs are more comprehensive than the current SRs and will ensure that the assumptions of the safety analysis are protected. The proposed change does not adversely affect any current plant safety margins or the reliability of the equipment assumed in the safety analysis. Therefore, there are no changes being made to any safety analysis assumptions, safety limits or limiting safety system settings that would adversely affect plant safety as a result of the proposed change.

Therefore, the proposed change does not involve a significant reduction in a margin of safety. Based on the above, APS concludes that the proposed change presents no significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and, accordingly, a finding of no significant hazards consideration is justified.

4.0 ENVIRONMENTAL EVALUATION The proposed change would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, or would change an inspection or surveillance requirement. However, the proposed change does not involve (i) a significant hazards consideration, (ii) a significant change in the types or a significant increase in the amounts of any effluent that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed change meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed change.

Enclosure Description and Assessment of Proposed Amendment to Implement TSTF 523

ATTACHMENT 1 Marked-up Technical Specification s Pages 3.4.6-3 3.4.7-3 3.4.8-2 3.5.3-2 3.6.6-2 3.9.4-2 3.9.5-3 RCS Loops

- MODE 4 3.4.6 PALO VERDE UNITS 1,2

,3 3.4.6-3 AMENDMENT NO.

188, SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.4.6.3 Verify correct breaker alignment and indicated power available to the required

pump that is not in operation.

In accordance

with the

Surveillance

Frequency

Control Program SR 3.4.6.4

NOTE------------------

Not required to be performed until 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months after entering MODE

4. ----------------------------------------

Verify required SDC train locations susceptible to gas accumulation are sufficiently filled with water

. In accordance with the Surveillance Frequency Control Program

RCS Loops - MODE 5, Loops Filled 3.4.7 PALO VERDE UNITS 1,2

,3 3.4.7-3 AMENDMENT NO.

188, SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.4.7.1 Verify one SDC train is in operation.

In accordance with the

Surveillance

Frequency

Control Program SR 3.4.7.2 Verify required SG secondary side water

level is

~ 25%. In accordance

with the

Surveillance

Frequency

Control Program SR 3.4.7.3 Verify correct breaker alignment and

indicated power available to the required

SDC pump that is not in operation.

In accordan ce with the

Surveillance

Frequency

Control Program SR 3.4.7.4

NOTE------------------

Not required to be performed until 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months after entering MODE

4. ----------------------------------------

Verify required SDC train locations susceptible to gas accumulation are sufficiently filled with water.

In accordance with the Surveillance Frequency Control Program

RCS Loops

- MODE 5, Loops Not Filled 3.4.8 PALO VERDE UNITS 1,2

,3 3.4.8-2 AMENDMENT NO.

188, ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME B. Required SDC trains inoperable.

OR No SDC train in

operation.

B.1 Suspend all

operations involving

reduction of RCS

boron concentration.

AND Immediately B.2 Initiate action to

restore one SDC train

to OPERABLE status

and operation.

Immediately SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.4.8.1 Verify one SDC train is in operation.

In accordance

with the

Surveillance

Frequency

Control Program SR 3.4.8.2 Verify correct breaker alignment and

indicated power available to the required

SDC pump that is not in operation.

In accordance

with the

Surveillance

Frequency Control Program SR 3.4.8.3 Verify SDC train locations susceptible to gas accumulation are sufficiently filled with water.

In accordance with the Surveillance Frequency Control Program

ECCS - Operating 3.5.3 PALO VERDE UNITS 1,2

,3 3.5.3-2 AMENDMENT NO.

188, SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY

NOTE------------------

Not required to be met for system vent flow paths opened under administrative control. ----------------

SR 3.5.3.1 Verify each ECCS manual, power operated, and automatic valve in the flow path, that

is not locked, sealed, or otherwise secured in position, is in the correct position.

In accordance with the

Surveillance

Frequency

Control Program SR 3.5.3.2 Verify ECCS piping is full of water.

Verify ECCS locations susceptible to gas accumulation are sufficiently filled with water. In accordance

with the

Surveillance

Frequency

Control Program SR 3.5.3.3 Verify each ECCS pump develops the required differential pressure at the flow test

point. In accordance

with the

Inservice

Testing Program SR 3.5.3.4 Verify each ECCS automatic valve that is not locked, sealed, or otherwise secured in position, in the flow path actuates to the

correct position on an actual or simulated actuation signal.

In accordance with the Surveillance

Frequency

Control Program SR 3.5.3.5 Verify each ECCS pump starts automatically

on an actual or simulated actuation signal.

In accordance

with the

Surveillance

Frequency

Control Program SR 3.5.3.6 Verify each LPSI pump stops on an actual or simulated actuation signal.

In accordance

with the

Surveillance

Frequency

Control Program (continued)

Containment Spray System 3.6.6 PALO VERDE UNITS 1,2, 3 3.6.6-2 AMENDMENT NO.

188, SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY

NOTE------------------

Not required to be met for system vent flow paths opened under administrative control. ---------------------------------------

__ SR 3.6.6.1 Verify each containment spray manual, power operated, and automatic valve in the flow

path that is not locked, sealed, or

otherwise secured in position is in the

correct position.

In accordance

with the

Surveillance

Frequency

Control Program SR 3.6.6.2 Verify the containment spray piping is

full of water to the 113 ft level in the

containment spray header.

In accordance

with the

Surveillance

Frequency

Control Program SR 3.6.6.3 Verify containment spray locations susceptible to gas accumulation are sufficiently filled with water.

In accordance with the Surveillance Frequency Control Program SR 3.6.6.

34 Verify each containment spray pump's developed head at the flow test point is

greater than or equal to the required

developed head.

In accordance

with the

Inservice

Testing Program SR 3.6.6.

45 Verify each automatic containment spray valve in the flow path that is not locked,

sealed, or otherwise secured in position,

actuates to the correct position on an actual or simulated actuation signal.

In accordance

with the

Surveillance

Frequency

Control Program SR 3.6.6.

56 Verify each containment spray pump starts automatically on an actual or simulated

actuation signal.

In accordance

with the

Surveillance

Frequency

Control Program SR 3.6.6.

67 Verify each spray nozzle is unobstructed.

In accordance

with the

Surveillance

Frequency

Control Program

SDC and Coolant Circulation

~High Water Level 3.9.4 PALO VERDE UNITS 1,2,3 3.9.4-2 AMENDMENT NO.

188, ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. (continued)

A.4 Close all containment penetrations

providing direct

access from

containment

atmosphere to outside

atmosphere.

4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.9.4.1 Verify one SDC loop is operable and in

operation.

In accordance

with the

Surveillance

Frequency

Control Program SR 3.9.4.2 Verify required SDC loop locations susceptible to gas accumulation are sufficiently filled with water.

In accordance with the Surveillance Frequency Control Program

SDC and Coolant Circulation

- Low Water Level 3.9.5 PALO VERDE UNITS 1,2

,3 3.9.5-3 AMENDMENT NO.

SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.9.5.3 Verify required SDC loop locations susceptible to gas accumulation are sufficiently filled with water.

In accordance with the Surveillance Frequency Control Program

Enclosure Description and Assessment of Proposed Amendment to Implement TSTF 523

ATTACHMENT 2 Revised Technical Specification s Pages (Clean Copy) 3.4.6-3 3.4.7-3 3.4.8-2 3.5.3-2 3.6.6-2 3.9.4-2 3.9.5-3 RCS Loops

- MODE 4 3.4.6 PALO VERDE UNITS 1,2

,3 3.4.6-3 AMENDMENT NO.

188, SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.4.6.3 Verify correct breaker alignment and indicated power available to the required

pump that is not in operation.

In accordance

with the

Surveillance

Frequency

Control Program SR 3.4.6.4

NOTE------------------

Not required to be performed until 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months after entering MODE

4. ---------------------------------

Verify required SDC train locations susceptible to gas accumulation are sufficiently filled with water

. In accordance with the Surveillance Frequency Control Program

RCS Loops - MODE 5, Loops Filled 3.4.7 PALO VERDE UNITS 1,2

,3 3.4.7-3 AMENDMENT NO.

188, SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.4.7.1 Verify one SDC train is in operation.

In accordance with the

Surveillance

Frequency

Control Program SR 3.4.7.2 Verify required SG secondary side water

level is

~ 25%. In accordance

with the

Surveillance

Frequency

Control Program SR 3.4.7.3 Verify correct breaker alignment and

indicated power available to the required

SDC pump that is not in operation.

In accordan ce with the

Surveillance

Frequency

Control Program SR 3.4.7.4

NOTE------------------

Not required to be performed until 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months after entering MODE

4. ----------------------------------------

Verify required SDC train locations susceptible to gas accumulation are sufficiently filled with water.

In accordance with the Surveillance Frequency Control Program

RCS Loops

- MODE 5, Loops Not Filled 3.4.8 PALO VERDE UNITS 1,2

,3 3.4.8-2 AMENDMENT NO.

188, ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME B. Required SDC trains inoperable.

OR No SDC train in

operation.

B.1 Suspend all

operations involving

reduction of RCS

boron concentration.

AND Immediately B.2 Initiate action to

restore one SDC train

to OPERABLE status

and operation.

Immediately SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.4.8.1 Verify one SDC train is in operation.

In accordance

with the

Surveillance

Frequency

Control Program SR 3.4.8.2 Verify correct breaker alignment and

indicated power available to the required

SDC pump that is not in operation.

In accordance

with the

Surveillance

Frequency Control Program SR 3.4.8.3 Verify SDC train locations susceptible to gas accumulation are sufficiently filled with water.

In accordance with the Surveillance Frequency Control Program

ECCS - Operating 3.5.3 PALO VERDE UNITS 1,2

,3 3.5.3-2 AMENDMENT NO.

188, SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY

NOTE------------------

Not required to be met for system vent flow paths opened under administrative control. ----------------

SR 3.5.3.1 Verify each ECCS manual, power operated,

and automatic valve in the flow path, that

is not locked, sealed, or otherwise secured in position, is in the correct position.

In accordance with the

Surveillance

Frequency

Control Program SR 3.5.3.2 Verify ECCS locations susceptible to gas

accumulation are sufficiently filled with

water. In accordance

with the

Surveillance

Frequency

Control Program SR 3.5.3.3 Verify each ECCS pump develops the required differential pressure at the flow test

point. In accordanc e

with the

Inservice

Testing Program SR 3.5.3.4 Verify each ECCS automatic valve that is not locked, sealed, or otherwise secured in position, in the flow path actuates to the

correct position on an actual or simulated actuation signal.

In accordance with the

Surveillance

Frequency

Control Program SR 3.5.3.5 Verify each ECCS pump starts automatically

on an actual or simulated actuation signal.

In accordance

with the

Surveillance

Frequency

Control Program SR 3.5.3.6 Verify each LPSI pump stops on an actual or simulated actuation signal.

In accordance

with the

Surveillance

Frequency

Control Program (continued)

Containment Spray System 3.6.6 PALO VERDE UNITS 1,2, 3 3.6.6-2 AMENDMENT NO.

188, SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY

NOTE------------------

Not required to be met for system vent flow paths opened under administrative control. ---------------------------------------

- SR 3.6.6.1 Verify each containment spray manual, power

operated, and automatic valve in the flow

path that is not locked, sealed, or

otherwise secured in position is in the

correct position.

In accordance

with the

Surveillance

Frequency

Control Program SR 3.6.6.2 Verify the containment spray piping is

full of water to the 113 ft level in the

containment spray header.

In accordance

with the

Surveillance

Frequency

Control Program SR 3.6.6.3 Verify containment spray locations

susceptible to gas accumulation are

sufficiently filled with water.

In accordance

with the

Surveillance

Frequency

Control Program SR 3.6.6.

4 Verify each containment spray pump's

developed head at the flow test point is

greater than or equal to the required

developed head.

In accordance

with the

Inservice

Testing Program SR 3.6.6.

5 Verify each automatic containment spray

valve in the flow path that is not locked,

sealed, or otherwise secured in position,

actuates to the correct position on an actual or simulated actuation signal.

In accordance

with the

Surveillance Frequency Control Program SR 3.6.6.

6 Verify each containment spray pump starts

automatically on an actual or simulated

actuation signal.

In accordance

with the

Surveillance

Frequency

Control Program SR 3.6.6.

7 Verify each spray nozzle is unobstructed.

In accordance with the Surveillance

Frequency

Control Program

SDC and Coolant Circulation

~High Water Level 3.9.4 PALO VERDE UNITS 1,2,3 3.9.4-2 AMENDMENT NO.

188, ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. (continued)

A.4 Close all containment penetrations

providing direct

access from

containment

atmosphere to outside

atmosphere.

4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.9.4.1 Verify one SDC loop is operable and in

operation.

In accordance

with the

Surveillance

Frequency

Control Program SR 3.9.4.2 Verify required SDC loop locations susceptible to gas accumulation are sufficiently filled with water.

In accordance with the Surveillance Frequency Control Program

SDC and Coolant Circulation

- Low Water Level 3.9.5 PALO VERDE UNITS 1,2

,3 3.9.5-3 AMENDMENT NO.

SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.9.5.3 Verify required SDC loop locations susceptible to gas accumulation are sufficiently filled with water.

In accordance with the Surveillance Frequency Control Program

Enclosure Description and Assessment of Proposed Amendment to Implement TSTF 523

ATTACHMENT 3

Marked-up Technical Specification Bases Pages B 3.4.6-3 B 3.4.6-5 B 3.4.6-6 B 3.4.6-7 B 3.4.7-4 B 3.4.7-6 B 3.4.7-7 B 3.4.7-8 B 3.4.8-2 B 3.4.8-4 B 3.4.8-5 B 3.5.3-4 B 3.5.3-8 B 3.5.3-9 B 3.5.3-10 B 3.5.4-2 B 3.6.6-5 B 3.6.6-7 B 3.6.6-8 B 3.6.6-9 B 3.9.4-2 B 3.9.4-4 B 3.9.4-5 B 3.9.5-2 B 3.9.5-4 B 3.9.5-5 B 3.9.5-6 RCS Loops

~ MODE 4 B 3.4.6 BASES ________________________________

________________________________

______________

(continued)

________________________________

______________

PALO VERDE UNITS 1,2

,3 B 3.4.6-3 REVISION 52 LCO Note 2 requires secondary side water temperature in each (continued)

SG is < 100 F above each of the RCS cold leg temperatures

before an RCP may be started with any RCS cold leg

temperature less than or equal to the LTOP enable

temperature specified in the PTLR.

Satisfying the above condition will preclude a large

pressure surge in the RCS when the RCP is started.

Note 3 restricts RCP operation t o no more than 2 RCPs with RCS cold leg temperature 200°F, and no more than 3 RCPs with RCS cold leg temperature >200°F but 500°F. Satisfying these conditions will maintain the analysis

assumptions of the flow induced pressure correction factors

due to RCP operation (Ref. 1)

An OPERABLE RCS loop consists of at least one OPERABLE RCP

and an SG that is OPERABLE and has the minimum water level

specified in SR 3.4.6.2.

Similarly, for the SDC System, an OPERABLE SDC train is

composed of an OPERABLE SDC pump (LPSI) capable of providing

flow to the SDC heat exchanger for heat removal. RCPs and

SDC pumps are OPERABLE if they are capable of being powered

and are able to provide flow

, if required.

Management of gas voids is important to SDC System OPERABILI TY. ________________________________

________________________________

______________

APPLICABILITY In MODE 4, this LCO applies because it is possible to remove

core decay heat and to provide proper boron mixing with

either the RCS loops and SGs or the SDC System.

Operation in other MODES is covered by:

LCO 3.4.4 "RCS Loops

-MODES 1 and 2"; LCO 3.4.5, "RCS Loops

- MODE 3";

RCS Loops

~ MODE 4 B 3.4.6 BASES (continued)

________________________________

______________

PALO VERDE UNITS 1,2

,3 B 3.4.6-5 REVISION 56 SURVEILLANCE SR 3.4.6.1 REQUIREMENTS

This SR requires verification that one required loop or train

is in operation and circulating reactor coolant at a flow rate

of greater than or equal to 4000 gpm. This ensures forced flow

is providing heat removal. Verification includes flow rate,

temperature, or pump status monitoring.

The Surveillance

Frequency is controlled under the Surveillance Frequency

Control Program

. SR 3.4.6.2 This SR requires verification of secondary side water level in

the required SG(s) 25% wide range. An adequate SG water level is required in order to have a heat sink for removal of

the core decay heat from the reactor coolant.

The Surveillance

Frequency is controlled under the Surveillance Frequency

Control Program

. SR 3.4.6.3 Verification that the required pump is OPERABLE ensures that an

additional RCS loop or SDC train can be placed in operation, if

needed to maintain decay heat removal and reacto r coolant

circulation. Verification is performed by verifying proper

breaker alignment and power available to the required pumps.

The Surveillance Frequency is controlled under the Surveillance

Frequency Control Program

. SR 3.4.6.4 SDC System piping an d components have the potential to develop voids and pockets of entrained gases. Preventing and managing gas intrusion and accumulation is necessary for proper operation of the required SDC train(s) and may also prevent water hammer, pump cavitation, and pumping of noncondensible gas into the reactor vessel.

Selection of SDC System locations susceptibl e to gas accumulation is based on a review of system design information, including piping instrumentation drawings, isometric drawings, plan and elevation drawings, and calculations. The design review is supplemented by system walk downs to validate the system high point s and to confirm the location and orientation of important components that can become source of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance or restoration. Susceptible locations depend on plant and system configuration, such as stand

-by versus operating conditions.

RCS Loops

~ MODE 4 B 3.4.6 BASES (continued)

________________________________

_______________

PALO VERDE UNITS 1,2

,3 B 3.4.6-6 REVISION 56 SURVEILLANCE SR 3.4.6.4 (continued)

REQUIREMENTS The SDC System is OPERABLE when it is sufficiently filled with water.

Acceptance criteria are established for the volume of accumulated gas at susceptible locations. If accumulated gas is discovered that exceeds the acceptance criteria for the susceptible location (or the volume of accumulated gas at one or more susceptible locations exceeds an acceptance criteria for gas volume at the s uction or discharge of a pump), the Surveillance is not met.

If the accumulated gas is eliminated or brought within the acceptance criteria limits during performance of the Surveillance, the SR is met and past system OPERABILITY is evaluated under the Cor rective Action Program.

If it is determined by subsequent evaluation that the SDC System is not rendered inoperable by the accumulated gas (i.e., the system is sufficiently filled with water), the Surveillance may be declared met. Accumulated gas should be eliminated or brought within the acceptance criteria limits.

SDC System locations susceptible to gas accumulation are monitored and, if gas is found, the gas volume is compared to the acceptance criteria for the location. Susceptible locations in the same system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub

-set of susceptible locations

. Monitoring may not be practical for locations that are inaccessible due to radiological or enviro nmental conditions, the plant configuration, or personnel safety.

For these locations alternative methods (e.g., operating parameters, remote monitoring) may be used to monitor the susceptible location. Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume has been evaluated and determined to not challenge system OPERABILITY. The accuracy of the method used for monitoring the susceptible locations and trending of the results should be suffici ent to assure system OPERABILITY during the Surveillance interval.

This SR is modified by a Note that states the SR is not required to be performed until 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months after entering MODE

4. In a rapid shutdown, there may be insufficient time to verify all susceptible locations prior to entering MODE

4.

RCS Loops

~ MODE 4 B 3.4.6 BASES (continued)

________________________________

______________

PALO VERDE UNITS 1,2

,3 B 3.4.6-7 REVISION 56 SURVEILLANCE SR 3.4.6.4 (continued)

REQUIREMENTS The Surveillance Frequency is controlled under the Surveillance Frequency Control Program. The Surveillance Frequency may vary by location susceptible to gas accumulation.

________________________________

______________

REFERENCES

1. PVNGS Operating License Amendments 52, 38 and 24 for

Units 1, 2 and 3, respectively, and associated NRC

Safety Evaluation dated July 25, 1990.

2. Not used. 3. PVNGS Calculation 13

-JC-SH-0200, Sect ion 2.9.

RCS Loops

~ MODE 5, Loops Filled B 3.4.7 BASES ________________________________

________________________________

_______________

________________________________

_______________

(continued)

PALO VERDE UNITS 1,2

,3 B 3.4.7-4 REVISION 54 LCO Note 5 provides for an orderly transition from MODE 5 to (continued)

MODE 4 during a planned heatup by permitting remova l of SDC trains from operation when at least one RCP is in operation.

This Note provides for the transition to MODE 4 where an RCP

is permitted to be in operation and replaces the RCS

circulation function provided by the SDC trains.

An OPERABLE SDC train is composed of an OPERABLE SDC pump

(CS or LPSI) capable of providing flow to the SDC heat

exchanger for heat removal.

Management of gas voids is important to SDC System OPERABILITY.

SDC pumps are OPERABLE if they are capable of being powered and are able to provide flow, if required. A SG can perform

as a heat sink when it is OPERABLE and has the minimum water

level specified in SR 3.4.7.2. The RCS loops may not be cons idered filled until two

conditions needed for operation of the steam generators are

met. First, the RCS must be intact. This means that all

removable portions of the primary pressure boundary (e.g.,

manways, safety valves) are securely fastened. Nozzle dams are removed. All manual drain and vent valves are closed,

and any open system penetrations (e.g., letdown, reactor

head vents) are capable of remote closure from the control

room. An intact primary allows the system to be pressurized

as needed to ac hieve the subcooling margin necessary to

establish natural circulation cooling. When the RCS is not

intact as described, a loss of SDC flow results in blowdown

of coolant through boundary openings that also could prevent

adequate natural circulation betwe en the core and steam

generators. Secondly, the concentration of dissolved or

otherwise entrained gases in the coolant must be limited or

other controls established so that gases coming out of

solution in the SG U

-tubes will not adversely affect natural

circulation. With these conditions met, the SGs are a

functional method of RCS heat removal upon loss of the

operating SDC train. The ability to feed and steam SGs at all times is not required when RCS temperature is less than

210°F because significant lo ss of SG inventory through

boiling will not occur during time anticipated to take

corrective action. The required SG level provides

sufficient time to either restore the SDC train or implement

a method for feeding and steaming the SGs (using non

-class components if necessary).

RCS Loops

~ MODE 5, Loops Filled B 3.4.7 BASES (continued)

________________________________

_______________

________________________________

_______________

(continued)

PALO VERDE UNITS 1,2

,3 B 3.4.7-6 REVISION 56 SURVEILLANCE SR 3.4.7.1 REQUIREMENTS This SR requires verification that one SDC train is in

operation and circulating reactor coolant at a flow rate of

greater than or equal to 3780 gpm. Verification includes

flow rate, temperature, or p ump status monitoring, which

help ensure that forced flow is providing decay heat

removal.

The Surveillance Frequency is controlled under the

Surveillance Frequency Control Program

. The SDC flow is established to ensure that core outlet

temperature is ma intained sufficiently below saturation to

allow time for swapover to the standby SDC train should the

operating train be lost.

SR 3.4.7.2 Verifying the SGs are OPERABLE by ensuring their secondary

side water levels are 25% wide range level ensures tha t redundant heat removal paths are available if the second SDC

train is inoperable. The Surveillance is required to be

performed when the LCO requirement is being met by use of

the SGs. If both SDC trains are OPERABLE, this SR is not

needed.

The Surveil lance Frequency is controlled under the

Surveillance Frequency Control Program

. SR 3.4.7.3 Verification that the second SDC train is OPERABLE ensures

that redundant paths for decay heat removal are available.

The requirement also ensures that the addit ional train can

be placed in operation, if needed, to maintain decay heat

removal and reactor coolant circulation. Verification is

performed by verifying proper breaker alignment and power

available to the required pumps. The Surveillance is

required to be performed when the LCO requirement is being

met by one of two SDC trains, e.g., both SGs have < 25% wide

range water level.

The Surveillance Frequency is controlled

under the Surveillance Frequency Control Program

. SR 3.4.7.4 SDC System piping and c omponents have the potential to develop voids and pockets of entrained gases. Preventing and managing gas intrusion and accumulation is necessary for proper operation of the required SDC train(s) and may also

RCS Loops

~ MODE 5, Loops Filled B 3.4.7 BASES (continued)

________________________________

______________

________________________________

______________

(continued)

PALO VERDE UNITS 1,2

,3 B 3.4.7-7 REVISION 56 SURVEILLANCE SR 3.4.7.

4 (continued)

REQUIREMENTS prevent water hammer, pump cavitation, and pumping of noncondensible gas into the reactor vessel.

Selection of SDC System locations susceptible to gas accumulation is based on a review of system design information, including piping and instrumentation drawings, isometric drawings, plan and elevation drawings, and calculations. The design review is supplemented by system walk downs to validate the sy stem high points and to confirm the location and orientation of important components that can become sources of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance of restoration.

Susceptible locations depend on plant and system configuration, such as stand

-by versus operating conditions.

The SDC Sy stem is OPERABLE when it is sufficiently filled with water. Acceptance criteria are established for the volume of accumulated gas at susceptible locations

. If accumulated gas is discovered that exceeds the acceptance criteria for the susceptible location (or the volume of accumulated gas at one or more susceptible locations exceeds an acceptance criteria for gas volume at the suction or discharge of a pump), the Surveillance is not met.

If the accumulated gas is eliminated or brought within the acceptanc e criteria limits during performance of the Surveillance, the SR is met and past system OPERABILITY is evaluated under the Corrective Action Program.

If it is determined by subsequent evaluation that the SDC Sys tem is not rendered inoperable by the accumu lated gas (i.e., the system is sufficiently filled with water), the Surveillance may be declared met. Accumulated gas should be eliminated or brought within the acceptance criteria limits.

SDC System locations susceptible to gas accumulation are monitored and, if gas is found

, the gas volume is compared to the acceptance criteria for the location. Susceptible locations in the sam e system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub

-set of susceptible locations. Monitoring may not be practical for locations that are inac cessible due to radiological or environme ntal conditions, the plant configuration, or personnel safety.

RCS Loops

~ MODE 5, Loops Filled B 3.4.7 BASES (continued)

________________________________

_______________

________________________________

_______________

(continued)

PALO VERDE UNITS 1,2

,3 B 3.4.7-8 REVISION 56 SURVEILLANCE SR 3.4.7.

4 (continued)

REQUIREMENTS For these locations alternative methods (e.g., operating parameters, remote monitoring) may be used to monitor the susceptible location. Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume has been evaluated and determined to not challenge system OPERABILITY. The accuracy of the method used for monitoring the s usceptible locations and trending of the results should be sufficient to assure system OPERABLITY during the Surveillance interval. This SR is modified by a Note that states the SR is not required to be performed until 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months after entering MODE 4. In a rapid shutdown

, there may be insufficient time to verify all susceptible locations prior to entering MODE 5. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program. The Surveillance Frequency may vary by location suscep tible to gas accumulation.

RCS Loops

~ MODE 5, Loops Not Filled B 3.4.8 BASES (continued)

________________________________

_______________

(continued

) ________________________________

________________________________

_______________

PALO VERDE UNITS 1,2

,3 B 3.4.8-2 REVISION 58 LCO Note 1 permits all SDC pumps to be de

-energized 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months per (continued) 8 hour9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months period. The circumstances for stopping both SDC pumps are to be limited to situations when the outage time is short

and the core outlet temperature is maintained >

10°F below saturation temperature.

The 10 degrees F is considered the

actual value of th e necessary difference between RCS core

outlet temperature and the saturation temperature associated

with RCS pressure to be maintained during the time the pumps

would be de

-energized. The instrument error associated with

determining this difference is le ss than 10 degrees F. (There

are no special restrictions for instrumentation use.)

Therefore, the indicated value of the difference between RCS

core outlet temperature and the saturation temperature

associated with RCS pressure must be greater than or equa l to 20 degrees F in order to use the provisions of the Note allowing the pumps to be de

-energized.

(Ref. 1) The Note

prohibits boron dilution or draining operations when SDC

forced flow is stopped.

Note 2 allows one SDC train to be inoperable for a peri od of 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months provided that the other train is OPERABLE and in

operation. This permits periodic surveillance tests to be

performed on the inoperable train during the only time when

these tests are safe and possible.

An OPERABLE SDC train is composed of a n OPERABLE SDC pump

(CS or LPSI) capable of providing flow to the SDC heat

exchanger for heat removal. SDC pumps are OPERABLE if they

are capable of being powered and are able to provide flow

,

if required.

Note that the CS pumps shall not be used for

normal operations if the water level is at or below the top

of the hot

-leg pipe (103'

- 1") due to concerns of potential

air entrainment and gas binding of the CS pump (Ref. 2).

Management of gas voids is important to SDC System OPERABILITY.

________________________________

_______________

APPLICABILITY In MODE 5 with loops not filled, this LCO requires core heat

removal and coolant circulation by the SDC System.

Operation in other MODES is covered by:

LCO 3.4.4, "RCS Loops

-MODES 1 and 2";

LCO 3.4.5, "RCS Loops

- MODE 3"; LCO 3.4.6, "RCS Loops

- MODE 4"; LCO 3.4.7, "RCS Loops

- MODE 5, Loops Filled";

LCO 3.9.4, "Shutdown Cooling (SDC) and Coolant

Circulation

- High Water Level" (MODE 6); and RCS Loops

~ MODE 5, Loops Not Filled B 3.4.8 BASES (continued)

________________________________

_______________

PALO VERDE UNITS 1,2

,3 B 3.4.8-4 REVISION 58 SURVEILLANCE SR 3.4.8.

3 REQUIREMENTS SDC System piping and components have the potential to develop voids and pockets of entrained gases. Preventing and managing gas intrusion and accumulation is necessary for proper operation of the SDC trains and may also prevent water hammer, pump cavitation, and pumping of noncondensible gas into the reactor vessel.

Selection of SDC System locations susceptible to gas accumulation is based on a review of system design information, including piping and instrumentation drawings, isometric drawings, plan and elevation drawings, and calculations. The design review is supplemented by system walk downs to validate the system high points and to confirm the location and orientation of important components that can become sources of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance or restoration. Susceptible locations depend on plant and system co nfiguration, such as stand

-by versus operating conditions.

The SDC System is OPERABLE when it is sufficiently filled with water. Acceptance criteria are established for the volume of accumulated gas at susceptible locations

. If accumulated gas is discov ered that exceeds the acceptance criteria for the susceptible location (or the volume of accumulated gas at one or more susceptible locations exceeds an acceptance criteria for gas volume at the suction or discharge of a pump),

the Surveillance is not met.

If the accumulated gas is eliminated or brought within the acceptance criteria limits during performance of the Surveillance, the SR is met and past system OPERABILITY is evaluated under the Corrective Action Program.

If it is determined by subsequent e valuation that the SDC System is not rendered inoperable by the a ccumulated gas (i.e., the system is sufficiently filled with water), the Surveillance may be declared met. Accumulated gas should be eliminated or brought within the acceptance criteria limi ts. SDC System locations susceptible to gas accumulation are monitored and, if gas is found, the gas volume is compared to the acceptance criteria for the location. Susceptible locations in the same system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub

-set of susceptible locations. Monitoring may not be practical for locations that are in accessible due to radiological or environmental conditions, the plant configuration, or personnel safety.

For these locations alternative methods (e.g., operating RCS Loops

~ MODE 5, Loops Not Filled B 3.4.8 BASES (continued)

________________________________

______________

PALO VERDE UNITS 1,2

,3 B 3.4.8-5 REVISION 58 SURVEILLANCE SR 3.4.8.3 (continued)

REQUIREMENTS parameters, remote monitoring) may be us ed to monitor the susceptible location. Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume has been evaluated and determined to not challenge system OPERABILITY. The accuracy of the method used fo r monitoring the susceptible locations and trending of the results should be sufficient to assure system OPERABILITY during the Surveillance interval.

The Surveillance Frequency is controlled under the Surveillance Frequency Control Program. The Surveill ance Frequency may vary by location susceptible to gas accumulation.

________________________________

______________

REFERENCES

1. PVNGS Calculation 13

-JC-SH-0200, Section 2.9.

2. PVNGS Calculation 13

-MC-SI-0250, Appendix C.

ECCS - Operating B 3.5.3 BASES ________________________________

________________________________

_______________

(continued)

________________________________

_______________

PALO VERDE UNITS 1,2

,3 B 3.5.3-4 REVISION 0 APPLICABLE The LCO ensures that an ECCS train will deliver sufficient SAFETY ANALYSES water to match decay heat boiloff rates soon enough to (continued) minimize core uncovery for a large LO CA. It also ensures that the HPSI pump will deliver sufficient water during a

small break LOCA and provide sufficient boron to maintain

the core subcritical following an SLB.

ECCS - Operating satisfies Criterion 3 of 10 CFR 50.36

(c)(2)(ii).

________________________________

_______________

LCO In MODES 1, 2, and 3, with pressurizer pressure

~ 1837 psia or with RCS T c ~ 485°F two independent (and redundant) ECCS trains are required to ensure that sufficient ECCS flow is

available, assuming there is a single failure affecting

either train. Additionally, individual components within

the ECCS trains may be called upon to mitigate the

consequences of other transients and accidents.

In MODES 1 and 2, and in MODE 3 with pressurizer pressure

~ 1837 psia or with RCS T c ~ 485°F an ECCS train consists of a HPSI subsystem and a LPSI subsystem.

Each train includes the piping, instruments, valves, and

controls to ensure the availability of an OPERABLE flow path

capable of taking suction from the RWT on a SIAS and

automatically transferring suction to the containment sump

upon a Recirculation Actuation Signal (RAS).

Management of gas voids is important to ECCS OPERABILITY.

During an event requiring ECCS actuation, a flow path is

provided to ensure an abundant supply of water from the RWT

to the RCS, via the HPSI and LPSI pumps and their respective

supply headers, to each of the four cold leg injection

nozzles. In the long term (post RAS), this flow path is

manually switched two to three hours after a LOCA to supply

part of its HPSI flow to the RCS hot legs via the HPSI hot

leg injection valves which connect to the Shutdown Cooling

(SDC) suction nozzle

s.

ECCS - Operating B 3.5.3 BASES (continued)

________________________________

_______________

(continued)

________________________________

_______________

PALO VERDE UNITS 1,2

,3 B 3.5.3-8 REVISION 56 SURVEILLANCE SR 3.5.3.1 REQUIREMENTS Verifying the correct alignment for manual, power operated,

and automatic valves in the ECCS flow paths provides

assurance that the proper flow paths will exist for ECCS

operation. This SR does not apply to valves that are

locked, sealed, or otherwise secured in position, since

these valves were verified to be in the correct position

prior to locking, sealing, or securing. A valve that

receives an actuation signal is allowed to be in a

nonaccident position provided the valve automatically

repositions within the proper stroke time. This

Surveillance does not require any testing or valve manipulation. Rather, it involves verification that those valves capable of being mispositioned are in t he correct

position.

The Surveillance Frequency is controlled under the

Surveillance Frequency Control Program

. The Surveillance is modified by a Note which exempts system vent flow paths opened under administrative control. The administrative control s hould be proceduralized and include stationing a ded icated individual at the system vent flow path who is in continuous communication with the operators in the control room. This individual will have a method to rapidly close the system vent flow path if directed. SR 3.5.3.2 With the exception of systems in operation, the ECCS piping pumps are normally in a standby, nonoperating mode. As such, flow path piping has the ECCS piping and components have the potential to develop voids and pockets of entrained gases. Preventing and managing gas intrusion and accumulation is necessary for proper operation of the ECCS and may also The method of ensuring that any voids or pockets of gases are removed from the ECCS piping is to vent the accessible discharge piping high points, which is controlled by PVNGS procedures. Maintaining the piping fro m the ECCS pumps to the RCS full of water ensures that the system will perform properly, injecting its full capacity into the RCS upon demand. This will also prevent water hammer, pump cavitation, and pumping of noncondensible gas

(e.g., air, nitrogen, or hydrogen) into the reactor vessel

. following an SIAS or during SDC.

The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.

ECCS - Operating B 3.5.3 BASES ________________________________

________________________________

______________

(continued)

________________________________

______________

PALO VERDE UNITS 1,2,3 B 3.5.3-9 REVISION 56 SURVEILLANCE SR 3.5.3.

2 (continued)

REQUIREMENTS Selection of ECCS locations susceptible to gas accumulation is based on a review of system design information, including piping and instrumentation drawings, isometric drawings, plan and elevation drawings, and calculations. The design review is supplemented by system walk downs to validate the sy stem high points and to confirm the location and orientation of important components that can become sources of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance or restoration. Susceptible locations depend on plant and system configuration, such as stand-by versus operating conditions.

The ECCS is OPERABLE when it is sufficiently filled with water. Acceptance criteria are established for the volume of accumulated gas at susceptible locations.

If accumulated gas is discovered that exceeds the acceptance criteria for the susceptible location (or the volume of accumulated gas at one or more susceptible locations exceeds an acceptance criteria for gas volume at the suction or discharge of a pump), the Surveillanc e is not met.

If the accumulated gas is eliminated or brought within the acceptance criteria limits during performance of the Surveillance, the SR is met and past system OPERABILITY is evaluated under the Corrective Action Program.

If it is determined by subsequent evaluation that the ECCS is not rendered inoperable by the accumulated gas (i.e., the system is sufficiently filled with water), the Surveillance may be declared met. Accumulated gas should be eliminated or brought within the acceptance criter ia limits.

ECCS locations susceptible to gas accumulation are monitored and, if gas is found, the gas volume is compared to the acceptance criteria for the location. Susceptible locations in the same system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub

-set of susceptible locations. Monitoring may not be practical for locations that are inaccessible due to radiological or environmental conditions, the plan t configuration, or personnel s afety. For these locations alternative methods (e.g., operating parameters, remote monitoring) may be used to monitor the susceptible location.

Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume h as been evaluated and det ermined to not challenge system OPERABILITY.

ECCS - Operating B 3.5.3 BASES ________________________________

________________________________

_______________

(continued)

________________________________

_______________

PALO VERDE UNITS 1,2,3 B 3.5.3-10 REVISION 56 SURVEILLANCE SR 3.5.3.2 (continued)

REQUIREMENTS The accuracy of the method used for monitoring the susceptible locations and trending of the results should be sufficient to assure system OPERABILITY during the Surveillance interval.

The Surveillance Frequency is controlled under the Surveillance Frequency Control Program. The Surveillance Frequency may vary by location susceptible to gas accumulation.

SR 3.5.3.3 Periodic surveill ance testing of ECCS pumps to detect gross degradation caused by impeller structural damage or other

hydraulic component problems is required by the ASME OM

Code. This type of testing may be accomplished by measuring

the pump developed head at only one po int of the pump

characteristic curve. This verifies both that the measured

performance is within an acceptable tolerance of the

original pump baseline performance and that the performance

at the test flow is greater than or equal to the performance

assumed in the unit safety analysis. SRs are specified in

the Inservice Testing Program, which encompasses the ASME OM

Code (Ref. 7). The frequency of this SR is in accordance

with the Inservice Testing Program.

SR 3.5.3.4, SR 3.5.3.5, and SR 3.5.3.6 These SRs demonstrate that each automatic ECCS valve

actuates to the required position on an actual or simulated

SIAS and on an RAS, that each ECCS pump starts on receipt of

an actual or simulated SIAS, and that the LPSI pumps stop on

receipt of an actual or s imulated RAS. This Surveillance is

not required for valves that are locked, sealed, or

otherwise secured in the required position under

administrative controls.

The Surveillance Frequency is

controlled under the Surveillance Frequency Control Program

. The following valve actuations must be verified:

on an actual or simulated recirculation actuation

signal, the containment sump isolation valves open,

and the HPSI, LPSI and CS minimum bypass recirculation ECCS - Shutdown B 3.5.4 BASES ________________________________

________________________________

_______________

(continued)

________________________________

_____________

PALO VERDE UNITS 1,2

,3 B 3.5.4-2 REVISION 0 LCO In MODE 3 with pressurizer pressure < 1837 psia and with RCS Tc < 485°F and in MODE 4 an ECCS subsystem is composed of a single HPSI subsystem. Each HPSI subsystem includes the

piping, instruments, valves, and controls to ensure an

OPERABLE flow path capable of taking suction from the RWT and transferring suction to the containment sump.

During an event requiring ECCS actuation, a flow path is

required to supply water from the RWT to the RCS via the

HPSI pumps and their respective supply headers to each of

the four cold leg injection nozzles. In the long term post

(RAS), this flow path is manually switched 2 to 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months

after a LOCA to supply part of its HPSI flow to the RCS hot

legs via the HPSI hot leg injection valves which connect to

the Shutdown Cooling (SDC) suction nozzles.

Management of gas voids is important to ECCS OPERABILITY.

With RCS pressure < 1837 psia and with RCS T c < 485°F, one HPSI pump is acceptable without single failure

consideration, based on the stable reactivity condition of

the reactor and the limited core cooling requirements. The

Low Pressure Safety Injection (LPSI) pumps may therefore be

released from the ECCS train for use in SDC.

________________________________

_______________

APPLICABILITY In MODES 1, 2, and 3 with RCS pressure 1837 psia or with RCS Tc 485°F, the OPERABILITY requirements for ECCS are covered by LCO 3.5.3.

In MODE 3 with RCS pressure < 1837 psia and with RCS T c < 485°F and in MODE 4, one OPERABLE ECCS train is acceptable

without singl e failure consideration, based on the stable

reactivity condition of the reactor and the limited core

cooling requirements.

In MODES 5 and 6, unit conditions are such that the

probability of an event requiring ECCS injection is

extremely low. Core cooling requirements in MODE 5 are

addressed by LCO 3.4.7, "RCS Loops

~ MODE 5, Loops Filled,"

and LCO 3.4.8, "RCS Loops

~ MODE 5, Loops Not Filled."

MODE 6 core cooling requirements are addressed by LCO 3.9.4,

"Shutdown Cooling (SDC) and Coolant Circulation

~ High Water Level," and LCO 3.9.5, "Shutdown Cooling (SDC) and Coolant

Circulation

- Low Water Level."

Containment Spray System B 3.6.6 BASES ________________________________

________________________________

______________

(continued)

________________________________

_____________

PALO VERDE UNITS 1,2

,3 B 3.6.6-5 REVISION 1 LCO containment spray actuation signal and automatically (continued) transferring suction to the containment sump on a recirculation actuation signal. Each spray train flow path

from the containment sump shall be via an OPERABLE shutdown

cooling heat exchanger.

Therefore, in the event of an accident, the minimum

requirements are met, assuming that the worst case single

active failure occurs.

Each Containment Spray System typically includes a spray

pump, a shutdown cooling heat exchanger, spray headers,

nozzles, valves, piping, instruments, and controls to ensure

an OPERABLE flow path capable of taking suction from the RWT

upon an ESF actuation signal and automatically transferring

suction to the containment sump.

Management of gas voids is important to Containment Spray System OPERABILITY.

________________________________

______________

APPLICABILITY In MODES 1, 2, and 3, and Mode 4 with RCS pressure

~ 385 psia, a DBA could cause a release of radioactive material to

containment and an increase in containment pressure and

temperature, requiring the operation of the containment

spray trains.

In MODE 4 with RCS pressure < 385 psia and MODES 5 and 6,

the probability and consequences of these events are reduced

due to the pressure and temperature limitations of these

MODES. Thu s, the Containment Spray System is not required

to be OPERABLE in these MODES.

________________________________

______________

ACTIONS A.1 With one containment spray train inoperable, the inoperable

containment spray train must be restored to OPERABLE status

within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . In this Condition, the remaining OPERABLE

spray train is adequate to perform the iodine removal,

hydrogen mixing, and containment cooling functions. The

72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time takes into account the redundant

heat removal capability afforded by the Containment Spray

System, reasonable time for repairs, and the low probability

of a DBA occurring during this period.

Containment Spray System B 3.6.6 BASES ________________________________

________________________________

______________

(continued)

________________________________

_____________

PALO VERDE UNITS 1,2

,3 B 3.6.6-7 REVISION 56 SURVEILLANCE SR 3.6.6.

1 (continued)

REQUIREMENTS The Surveillance is modified by a Note which exempts system and vent flow paths opened under administrative control.

The administrative control should be proceduralized and include stationing a dedicated individual at the system vent flow path who i s in continuous communication with the operators in the control room. This individual will have a method to rapidly close the system vent flow path if directed.

SR 3.6.6.2 Verifying that the containment spray header piping is full of water to the 113 ft level minimizes the time required to

fill the header. This ensures that spray flow will be

admitted to the containment atmosphere within the time frame

assumed in the containment analysis. The analyses shows

that the header may be filled with unborated water which

helps to reduce boron plate out due to evaporation.

The Surveillance Frequency is controlled under the Surveillance

Frequency Control Program

. The value of 113 ft is an

indicated value which accounts for instrument uncertainty.

SR 3.6.6.3 Containment Spray System piping and components have the potential to develop voids and pockets of entrained gases.

Preventing and managing gas intrusion and accumulation is necessary for proper operation of the required containment spray trains and may al so prevent water hammer and pump cavitation.

Selection of Containment Spray System locations susceptible to gas accumulation is based on a review of system design information, including piping and instrumentation drawings, isometric drawings, plan and elev ation drawings, and calculations. The design review is supplemented by system walk downs to validate the system high points and to confirm the location and orientation of important components that can become sources of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance or restoration.

Susceptible locations depend on plant and system configuration, such as stand

-by versus operating conditions.

Containment Spray System B 3.6.6 BASES ________________________________

________________________________

_______________

(continued)

________________________________

_____________

PALO VERDE UNITS 1,2

,3 B 3.6.6-8 REVISION 56 SURVEILLANCE SR 3.6.6.3 (continued)

REQUIREMENTS The Containment Spray System is OPERABLE when it is sufficiently filled with water. Acceptance criteria are established for the volume of accumulated gas at susceptible locations. If accumulated gas is discovered that exceeds the acceptance criteria for the susceptible location (or the volume of accumulated gas at one or more susceptible locations exceeds an acceptance criteria for gas volume at the suction or discharge of a pump), the Surveillance is not met. If the accumulated gas is eliminated or brought within the acceptance criteria limits during performance of the Surveillance, the SR is met and past system OPERABILITY is evaluated under the Corrective Action Program.

If it is determined by subsequent evaluation that the Containm ent Spray System is not rendered in operable by the accumulated gas (i.e., the system is sufficiently filled with water),

the Surveillance may be declared met. Accumulated gas should be eliminated or brought within the acceptance criteria limit.

Containment Spray System locations susceptibl e to gas accumulation are monitored and, if gas is found, the gas volume is compared to the acceptance criteria for the location. Susceptible locations in the sam e system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub

-set of susceptible locations. Monitoring may not be practical for locations that are inaccessible due to radiological or environmental conditions, the plant configuration or personnel safety. For these locations alternativ e methods (e.g., operating parameters, remote monitoring) may be used to monitor the susceptible location. Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume has been evaluated and determined to no t challenge system OPERABILITY. The accuracy of the method used for monitoring the susceptible locations and trending of the results should be sufficient to assure system OPERABILITY during the Surveillance interval.

The Surveillance Frequency is controlled under the Surveillance Frequency Control Program. The Surveillance Frequency may vary by location susceptible to gas accumulation.

Containment Spray System B 3.6.6 BASES ________________________________

________________________________

______________

________________________________

_____________

(continued)

PALO VERDE UNITS 1,2

,3 B 3.6.6-9 REVISION 56 SURVEILLANCE SR 3.6.6.34 REQUIREMENTS (continued)

Verifying that each containment spray pump's developed head

at the flow test point is greater than or equal to the

required developed head ensures that spray pump performance

has not degraded during the cycle. Flow a nd differential

pressure are normal tests of centrifugal pump performance

required by the ASME OM Code (Ref. 6). Since the

containment spray pumps cannot be tested with flow through

the spray headers, they are tested on recirculation flow

(either full flo w or miniflow as conditions permit). This

test is indicative of overall performance. Such inservice

inspections confirm component OPERABILITY, trend

performance, and detect incipient failures by indicating

abnormal performance. The Frequency of this SR is in accordance with the Inservice Testing Program.

SR 3.6.6.

4 5 and SR 3.6.6.

56 These SRs verify that each automatic containment spray valve

actuates to its correct position and that each containment

spray pump starts upon receipt of an actual or simul ated safety injection actuation signal, recirculation actuation

signal and containment spray actuation signal as applicable.

This Surveillance is not required for valves that are

locked, sealed, or otherwise secured in the required

position under administ rative controls.

The Surveillance

Frequency is controlled under the Surveillance Frequency

Control Program

. The surveillance of containment sump isolation valves is

also required by SR 3.5.3.5. A single surveillance may be

used to satisfy both requireme nts. SR 3.6.6.

67 Unobstructed flow headers and nozzles are determined by

either flow testing or visual inspection.

With the containment spray inlet valves closed and the spray

header drained of any solution, low pressure air or smoke

can be blown through test connections. Performance of this

SR demonstrates that each spray nozzle is unobstructed and

provides assurance that spray coverage of the containment

during an accident is not degraded.

The Surveillance

Frequency is controlled under the Surveillance Frequency

Control Program

.

SDC and Coolant Circulation

- High Water Level B 3.9.4 BASES (continued)

________________________________

_______________

(continued)

________________________________

_______________

PALO VERDE UNITS 1,2,3 B 3.9.4-2 REVISION 54 LCO Only one SDC loop is required for decay heat removal in MODE 6, with water level

~ 23 ft above the top of the reactor vessel flange. Only one SDC loop is required

because the volume of water above the reactor vessel flange

provides backup decay heat removal capability. At least one

SDC loop must be in operati on to provide:

a. Removal of decay heat;

b. Mixing of borated coolant to minimize the possibility

of a criticality; and

c. Indication of reactor coolant temperature.

An OPERABLE SDC train is composed of an OPERABLE SDC pump

(LPSI or CS) capable of pro viding flow to the SDC heat

exchanger for heat removal. SDC pumps are OPERABLE if they are capable of being powered and are able to provide flow

,

if required.

Management of gas voids is important to SDC System OPERABILITY.

The LCO is modified by a Note that allows the required

operating SDC loop to be removed from service for up to

1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months in each 8 hour9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months period, provided no operations are

permitted that would cause a reduction of the RCS boron

concentration. Boron concentration reduction is prohibited

because uniform concentration distribution cannot be ensured

without forced circulation. This permits operations such as

core mapping or alterations in the vicinity of the reactor

vessel hot leg nozzles, surveillance testing of ECCS pumps,

and RCS to SDC is olation valve testing. During this 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months

period, decay heat is removed by natural convection to the

large mass of water in the refueling cavity.

________________________________

_______________

APPLICABILITY One SDC loop must be in operation in MODE 6, with the water

level ~ 23 ft above the top of the reactor vessel flange, to provide decay heat removal. The 23 ft level was selected

because it cor responds to the 23 ft requirement established

for fuel movement in LCO 3.9.6, "Refueling Water Level

-

Fuel Assemblies."

SDC and Coolant Circulation

- High Water Level B 3.9.4 BASES ________________________________

________________________________

_______________

PALO VERDE UNITS 1,2

,3 B 3.9.4-4 REVISION 56 ACTIONS A.4 (continued)

If SDC loop requirements are not met, all containment

penetrations to the outside atmosphere must be closed to

prevent fission products, if released by a loss of decay

heat event, from escaping the containment building. The

4 hour4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months Completion Time allows fixing most SDC problems

without incurring the additional action of violating the

containment atmosphere.

________________________________

_______________

SURVEILLANCE SR 3.9.4.1 REQUIREMENTS

This Surveillance demonstrates that the SDC loop is in

operation and circulating reactor coolant at a flowrate of

greater than or equal to 3780 gpm. The flow rate is

determined by the flow rate necessary to provide sufficient

decay heat removal capability and to prevent thermal and

boron stratification in the core.

The Surveillance

Frequency is controlled under the Surveillance Frequency

Control Program.

SR 3.9.4.2 SDC System piping and components have th e potential to develop voids and pockets of entrained gases. Preventing and managing gas intrusion and accumulation is necessary for proper operation of the required SDC loop(s) and may also prevent water hammer, pump cavitation, and pumping of noncondensible gas into the reactor vessel.

Selection of SDC System locations susceptible to gas accumulation is based on a review of system design information including piping and instrumentation drawings, isometrics drawings, plan and elevation drawings, and calculations. The design review is supplemented by system walk downs to validate the system high points and to confirm the location and orientation of important components that can become sources of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance or restoration. Susceptible loca tions depend on plant and system configuration, such as stand

-by versus operating conditions.

SDC and Coolant Circulation

- High Water Level B 3.9.4 BASES ________________________________

________________________________

______________

PALO VERDE UNITS 1,2

,3 B 3.9.4-5 REVISION 56 SURVEILLANCE SR 3.9.4.

2 (continued)

REQUIREMENTS The SDC System is OPERABLE when it is sufficiently filled with water. Acceptance criteria are established for the volume of accumulated gas at susceptible locations. If accumulated gas is discovered that exceeds the acceptance criteria for the susceptible location (or the volume of acceptance criteria for gas volume at the suction or discharge of a pump), the Surveillance is not met.

If the accumulated gas is eliminated or brought within the acceptance criteria limits during performance of the Surveillance

, the SR is met and past system OPERABILITY is evaluated under the Corrective Action Program.

If it is determined by subsequent evaluation that the SDC System is not rendered inoperable by the accumulated gas (i.e., the system is sufficiently filled with water), the Surveillance may be declared met. Accumulated gas should be eliminated or brought within the acceptance criteria limits.

SDC System locations susceptible to gas accumulation are monitored and, if gas is found, the gas volume is compared to the acceptance criteria for the location. Susceptible locations in the same system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub

-set of susceptible locations. Monitoring may not be practical for locations that are inaccessible due to radiological or environmental conditions, the plant configuration, or personnel safety.

For these locations alternative methods (

e.g., operating parameters, remote monitoring) may be used to monitor the susceptible location. Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume has been evaluated and determined to not challenge system OPERABILITY. The accuracy of the method used for monitoring the suscep tible locations and trending of the results should be sufficient to assure system OPERABILITY during the Surveillance interval.

The Surveillance Frequency is controlled under the Surveillance Frequency Control Program. The Surveillance Frequency may vary by location susceptible to gas accumulation.

SDC and Coolant Circulation

- Low Water Level B 3.9.5 BASES ________________________________

________________________________

_______________

________________________________

________________

(continued)

PALO VERDE UNITS 1,2

,3 B 3.9.5-2 REVISION 58 LCO In MODE 6, with the water level < 23 ft above the top of the reactor vessel flange, both SDC loops must be OPERABLE.

Additionally, on e loop of the SDC System must be in

operation in order to provide:

a. Removal of decay heat;

b. Mixing of borated coolant to minimize the possibility of a criticality; and

c. Indication of reactor coolant temperature.

An OPERABLE SDC train is composed of an OPERABLE SDC pump (LPSI or CS) capable of providing flow to the SDC heat exchanger for

heat removal. SDC pumps are OPERABLE if they are capable of

being powered and are able to provide flow, if required.

Note that the CS pumps shall not be used for normal operations if

the water level is at or below the top of the hot

-leg pipe

(103' - 1") due to concerns of potential air entrainment and

gas binding of the CS pump (Ref. 2).

Management of gas voids is important to SDC System OPERABILITY.

Both SDC pu mps may be aligned to the Refueling Water Tank

(RWT) to support filling the refueling cavity or for

performance of required testing.

The LCO is modified by a Note that allows a required operating

SDC loop to be removed from service for up to 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months in eac h 8 hour9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months period, provided no operations are permitted that would

cause a reduction of the RCS boron concentration. Boron

concentration reduction is prohibited because uniform

concentration distribution cannot be ensured without forced

circulation. This p ermits operations such as core mapping or

alterations in the vicinity of the reactor vessel hot leg

nozzles, surveillance testing of ECCS pumps, and RCS to SDC

isolation valve testing. During this 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months period, decay

heat is removed by natural convection to the large mass of

water in the refueling cavity.

This LCO is modified by a Note that allows one SDC loop to be inoperable for a period of 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months provided the other loop is

OPERABLE and in operation. Prior to declaring the loop

inoperable, consideration should be given to the existing

plant configuration. This consideration should include that

the core time to boil is not short, there is no draining

operation to further reduce RCS water level and that the

capacity exists to inject borated water into the reactor

vessel. This permits surveillance tests to be performed on

the non-operating loop during a time when these tests are

safe and possible.

SDC and Coolant Circulation

- Low Water Level B 3.9.5 BASES ________________________________

________________________________

_______________

PALO VERDE UNITS 1,2

,3 B 3.9.5-4 REVISION 58 ACTIONS B.3 (Continued) the containment atmosphere to the outside atmosphere must be

closed within 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months . With the SDC loop requirements not

met, the potential exists for the coolant to boil and

release radioactive gas to the containment atmosphere.

Closing containment penetrations that are open to the

outside atmosphere ensures that dose limits are not

exceeded.

The Completion Time of 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months is reasonable, based on the

low probability of the coolant boiling in that time

. ________________________________

________________________________

_______________

SURVEILLANCE SR 3.9.5.1 REQUIREMENTS

This Surveillance demonstrates that one SDC loop is

operating and circulating reactor coolant at a flowrate of

greater than or equal to 3780 gpm. The flow rate is

determined by the flow rate necessary to provide sufficient

decay heat removal capability and to prevent thermal and

boron stratification in the core. In addition, this

Surveillance demonstrates that the other SDC loop is

OPERABLE.

In addition, during operation of the SDC loop with the water

level in t he vicinity of the reactor vessel nozzles, the SDC

loop flow rate determination must also consider the SDC pump

suction requirements.

The Surveillance Frequency is

controlled under the Surveillance Frequency Control Program

. SR 3.9.5.2 Verification that the required pump that is not in operation

is OPERABLE ensures that an additional SDC pump can be

placed in operation, if needed, to maintain decay heat

removal and reactor coolant circulation. Verification is

performed by verifying prop er breaker alignment and power

available to the required pump.

The Surveillance Frequency

is controlled under the Surveillance Frequency Control

Program. SR 3.9.5.3 SDC System piping and components have the potential to develop voids and pockets of ent rained gases. Preventing and managing gas intrusion and accumulation is necessary for proper operation of the SDC loops and may also prevent water hammer, pump cavitation, and pumping of noncondensible gas into the reactor vessel.

SDC and Coolant Circulation

- Low Water Level B 3.9.5 BASES ________________________________

________________________________

_______________

PALO VERDE UNITS 1,2

,3 B 3.9.5-5 REVISION 58 SURVEILLANCE SR 3.9.5.3 (continued)

REQUIREMENTS Selection of SDC System locations susceptible to gas accumulation is based on a review of system design information, including piping and instrumentation drawings, isometric drawings, plan and elevation drawings, and calculation

s. The design review is supplemented by system walk downs to validate the system high points and to confirm the location and orientation of important components that can become sources of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance or restoration. Susceptible locations depend on plant and system configuration, such as stand-by versus operating conditions.

The SDC System is OPERABLE when it is sufficiently filled with water. Acceptance criteria are est ablished for the volume of accumulated gas at susceptible locations. If accumulated gas is discovered that exceeds the acceptance criteria for the susceptible location (or the volume of accumulated gas at one or more susceptible locations exceeds an accep tance criteria for gas volume at the suction or discharge of a pump), the Surveillance is not met.

If the accumulated gas is eliminated or brought within the acceptance criteria limits during performance of the Surveillance, the SR is met and past system OPERABILITY is evaluated under the Corrective Action Program.

If it is determined by subsequent evaluation that the SDC System is not rendered inoperable by the accumulated gas (i.e.,

the system is sufficiently filled with water)

, the Surveillance may be declared met. Accumulated gas should be eliminated or brought within the acceptance criteria limits.

SDC System locations susceptible to gas accumulation are monitored and, if gas is found, the gas volume is compared to the acceptance criteria for the location

. Susceptible locations in the same system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub-set of susceptible locations. Monitoring may not be practical for locations that are inaccessible due to radiological or environmental conditions, the plant configuration

, or personnel safety

. For these locat ions alternative meth ods (e.g., operating parameters, remote monitoring) may be used to monitor the susceptible location.

Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume has been evaluated and determined to not challenge system OPERABI LITY. The accuracy of the method used for monitoring the susceptible locations and trending of the results should be sufficient to assure system OPERABILITY during the Surveillance interval.

SDC and Coolant Circulation

- Low Water Level B 3.9.5 BASES ________________________________

________________________________

_______________

PALO VERDE UNITS 1,2

,3 B 3.9.5-6 REVISION 58 SURVEILLANCE SR 3.9.5.3 (continued)

REQUIREMENTS The Surveillance Frequency is controlled under the Surveillance Frequency Control Program. the Surveillance Frequency may vary by location susceptible to gas accumulation.

________________________________

_______________

REFERENCES

1. UFSAR, Section 5.4.7.

2. PVNGS Calculation 13

-MC-SI-0250, Appendix C.

v t e Letter Sequence Request
CAC:MF8082, Generic Letter 2008-01, Managing Gas Accumulation (Approved, Closed)
Initiation Request Acceptance Administration Questions Answers Results Approval Other: ML16291A448
MONTHYEAR2016-06-29 [Table View]

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2.0 ASSESSMENT

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ML16182A171: Difference between revisions

Revision as of 05:14, 30 June 2018

Text

Dear Sirs:

Subject:

Enclosure:

2.0 ASSESSMENT

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