ML16182A171
| 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) | |
Text
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, 201 6 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, 5 0-529, 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, 20 08 [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 PVNG S TS. 2.2 Optional Changes and Variations P VNGS TS utilize different numbering than the Standard Technical Specification s (STS) on which TST F-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 <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> 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 <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after entry into MODE 4. Allowing a duration of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> 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 <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
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 R EGULATORY 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 S Rs 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 do es 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 <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> 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 L oops - 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------------------
N ot required to be performed until 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> 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.
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 Freque ncy 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 P ALO 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
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.
3 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.
4 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.
5 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.
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 <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> 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 <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> 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 L oops - 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------------------
N ot required to be performed until 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> 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.
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 Freque ncy 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 P ALO 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
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 <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> 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:
-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
Frequenc y 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 p u mping of noncondensible gas into the reactor vessel.
Selection of SDC System locations susceptibl e to gas accumul ation 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 <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> 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
c irculation. 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 com ponents 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)
REQUIR EMENTS 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 s tem 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 c essible 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 in terval. This SR is modified by a Note that states the SR is not required to be performed until 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> 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 a ccumulation.
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 <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> per (continued) 8 ho ur 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 <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> 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
nor mal 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:
-MODES 1 and 2";
- 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 w a ter 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 sy s tem 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
non accident 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 p roper 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 v olume 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 int rusion 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
assume d 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 Thes e 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 T c < 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 <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />
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.
Man agement 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 T c 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
te mperature, 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 <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. 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 <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> 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)
REQUIREM ENTS 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 a cceptance 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 c ompared 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 3.6.6.3 4 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.
4 5 and SR 3.6.6.
5 6 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.
6 7 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
,
i f 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 <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> in each 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> period, provided no operations are
permitted that would cause a reduction of the RCS boron
concentration. Boron concentration reduction is prohibited
be cause 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 <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />
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 eve nt, from escaping the containment building. The
4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> 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
bo ron 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 m anaging 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 loc ation 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 sy s tem 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 practi cal 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 susce ptible 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 <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> in eac h 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 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 <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> 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 <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> 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 <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. 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 <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> 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 remo ve 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 Surv eillance 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 m onitored 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 i ons 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.