ML17341A327
| ML17341A327 | |
| Person / Time | |
|---|---|
| Site: | Technical Specifications Task Force |
| Issue date: | 03/26/2018 |
| From: | NRC/NRR/DSS |
| To: | |
| Honcharik M | |
| Shared Package | |
| ML17341A333 | List: |
| References | |
| CAC MF9568, EPID L 2017 PMP 0005 | |
| Download: ML17341A327 (12) | |
Text
Enclosure 1 1
DRAFT SAFETY EVALUATION 2
BY THE OFFICE OF NUCLEAR REACTOR REGULATION 3
TECHNICAL SPECIFICATIONS TASK FORCE TRAVELER 4
TSTF-567, REVISION 1 5
ADD CONTAINMENT SUMP TS TO ADDRESS GSI-191 ISSUES 6
USING THE CONSOLIDATED LINE ITEM IMPROVEMENT PROCESS 7
(CAC NO. MF9568, EPID L-2017-PMP-0005) 8 9
10
1.0 INTRODUCTION
11 12 By letter dated August 2, 2017 (Agencywide Documents Access and Management System 13 (ADAMS) Accession No. ML17214A813), the Technical Specifications Task Force (TSTF) 14 submitted Traveler TSTF-567, Revision 1, Add Containment Sump TS [Technical Specification]
15 to Address GSI [Generic Safety Issue]-191 Issues. Traveler TSTF-567, Revision 1, proposes 16 changes to the Standard Technical Specifications (STSs) for pressurized-water reactor (PWR) 17 designs.1 These changes would be incorporated into future revisions of NUREG-1430, 18 Volume 1, NUREG-1431, Volume 1, and NUREG-1432, Volume 1. There were no bases 19 changes proposed.
20 21 The proposed changes would revise STS Limiting Condition for Operation (LCO) 3.5.2, ECCS 22
[Emergency Core Cooling System]-Operating, LCO 3.5.3, ECCS-Shutdown, and TS 23 Section 5.5.15, Safety Function Determination Program (SFDP). The proposed changes 24 would also add a TS LCO, Containment Sump, to Section 3.6, Containment Systems. This 25 STS change will be made available to licensees through the consolidated line item improvement 26 process (CLIIP).
27 28 Revision 1 of TSTF-567 is not applicable to non-STS plants due to its dependence on 29 LCO 3.0.6 and the SFDP.
30 31
2.0 REGULATORY EVALUATION
32 33
2.1 DESCRIPTION
OF STS SECTIONS 34 35 LCOs specify minimum requirements for ensuring safe operation of the plant. The actions 36 associated with an LCO state conditions that typically describe the ways in which the 37 1 U.S. Nuclear Regulatory Commission, Standard Technical Specifications, Babcock and Wilcox Plants, NUREG-1430, Volume 1, Specifications, Revision 4.0, April 2012 (ADAMS Accession No. ML12100A177).
U.S. Nuclear Regulatory Commission, Standard Technical Specifications, Westinghouse Plants, NUREG-1431, Volume 1, Specifications, Revision 4.0, April 2012 (ADAMS Accession No. ML12100A222).
U.S. Nuclear Regulatory Commission, Standard Technical Specifications, Combustion Engineering Plants, NUREG-1432, Volume 1, Specifications, Revision 4.0, April 2012 (ADAMS Accession No. ML12102A165).
requirements of the LCO can fail to be met. Specified with each stated condition are required 1
action(s) and completion time(s).
2 3
2.1.1 LCO 3.5.2, ECCS-Operating 4
5 The function of the ECCS is to provide core cooling and negative reactivity to ensure the reactor 6
core is protected after any of the following accidents:
7 8
- a. Loss-of-coolant accident (LOCA), coolant leakage greater than the capability of the 9
normal charging system, 10 11
- b. Rod ejection accident, 12 13
- c. Loss of secondary coolant accident, including uncontrolled steam release or loss of 14 feedwater, and 15 16
- d. Steam generator tube rupture.
17 18 LCO 3.5.2 is applicable in Modes 1, 2, and 3 and requires that two ECCS trains be operable to 19 ensure that sufficient ECCS flow is available, assuming a single failure affecting either train.
20 21 LCO 3.5.2 helps ensure the following acceptance criteria for ECCS, established by Title 10 of 22 the Code of Federal Regulations (10 CFR) 50.46, will be met following a LOCA:
23 24
- a. Maximum fuel element cladding temperature is 2200 degrees Fahrenheit (°F),
25 26
- b. Maximum cladding oxidation is 0.17 times the total cladding thickness before 27 oxidation, 28 29
- c. Maximum hydrogen generation from a zirconium water reaction is 0.01 times the 30 hypothetical amount generated if all of the metal in the cladding cylinders surrounding 31 the fuel, excluding the cladding surrounding the plenum volume, were to react, 32 33
- d. Core is maintained in a coolable geometry, and 34 35
- e. Adequate long-term core cooling capability is maintained.
36 37 LCO 3.5.2 also limits the potential for a post-trip return to power following a main steam line 38 break event and ensures that containment temperature limits are met.
39 40 2.1.2 LCO 3.5.3, ECCS-Shutdown 41 42 LCO 3.5.3 is applicable in Mode 4 and requires one of the two ECCS trains to be operable to 43 ensure that sufficient ECCS flow is available to the core following a design-basis accident.
44 45 2.1.3 TS Section 5.5.15, Safety Function Determination Program (SFDP) 1 2
Section 5.5.15 establishes the SFDP which implements the requirements of LCO 3.0.6. The 3
SFDP ensures loss of safety function is detected and appropriate actions are taken. Upon entry 4
into LCO 3.0.6, an evaluation shall be made to determine if loss of safety function exists.
5 Additionally, other appropriate actions may be taken as a result of the support system 6
inoperability and corresponding exception to entering supported system(s) condition(s) and 7
required action(s).
8 9
2.2 PROPOSED CHANGE
S TO THE STSs 10 11 The proposed changes would revise LCO 3.5.2, ECCS-Operating, LCO 3.5.3, 12 ECCS-Shutdown, and Section 5.5.15, Safety Function Determination Program (SFDP). The 13 proposed changes would also add a new STS LCO, Containment Sump, to Section 3.6, 14 Containment Systems. The proposed changes are described below.
15 16 2.2.1 Proposed Changes to LCO 3.5.2, ECCS-Operating 17 18 STS LCO 3.5.2 for Babcock and Wilcox (B&W) plants currently contains Surveillance 19 Requirement (SR) 3.5.2.9 (SR 3.5.2.8 for Westinghouse (W) plants and SR 3.5.2.10 for 20 Combustion Engineering (CE) plants). This SR requires the following at a frequency of 21 18 months or in accordance with the Surveillance Frequency Control Program (SFCP):
22 23 Verify, by visual inspection, each ECCS train containment sump 24 suction inlet is not restricted by debris and suction inlet trash racks 25 and screens show no evidence of structural distress or abnormal 26 corrosion.
27 28 Traveler TSTF-567, Revision 1, proposed to modify and move this SR (B&W SR 3.5.2.9, W 29 SR 3.5.2.8, and CE SR 3.5.2.10) from LCO 3.5.2 and include it in the new containment sump 30 LCO.
31 32 This change is evaluated in Section 3.1 of this safety evaluation (SE).
33 34 2.2.2 Proposed Changes to LCO 3.5.3, ECCS-Shutdown 35 36 STS LCO 3.5.3 currently contains SR 3.5.3.1 which refers to applicable SRs under LCO 3.5.2.
37 The applicable SRs are B&W SR 3.5.2.9, W SR 3.5.2.8, and CE SR 3.5.2.10, as described in 38 Section 2.2.1 of this SE.
39 40 Because TSTF-567, Revision 1, proposed to modify and move the referenced SRs (B&W 41 SR 3.5.2.9, W SR 3.5.2.8, and CE SR 3.5.2.10) from LCO 3.5.2 and include it in the new 42 containment sump LCO, the references to these SRs (B&W SR 3.5.2.9, W SR 3.5.2.8, and CE 43 SR 3.5.2.10), in SR 3.5.3.1 would be deleted.
44 45 This change is evaluated in Section 3.2 of this SE.
46 47 2.2.3 Proposed Changes to Section 5.5.15, Safety Function Determination 1
Program (SFDP) 2 3
Traveler TSTF-567, Revision 1, proposed to add the following sentence at the end of TS 4
Section 5.5.15:
5 6
When a loss of safety function is caused by the inoperability of a 7
single Technical Specification support system, the appropriate 8
Conditions and Required Actions to enter are those of the support 9
system.
10 11 This change is evaluated in Section 3.3 of this SE.
12 13 2.2.4 Proposed Addition of a New Containment Sump LCO 14 15 Traveler TSTF-567, Revision 1, proposed to add an LCO (LCO 3.6.8 for B&W plants, 16 LCO 3.6.19 for W plants, and LCO 3.6.13 for CE plants) requiring the containment sump to be 17 operable during Modes 1, 2, 3, and 4. Condition A specifies that if the containment sump is 18 inoperable due to containment accident generated and transported debris exceeding the 19 analyzed limits, Required Actions A.1, A.2, and A.3 require initiation of action to mitigate 20 containment accident generated and transported debris immediately, perform SR 3.4.13.1 once 21 per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, and restore the containment sump to operable status in 90 days, respectively.
22 SR 3.4.13.1 requires verification of reactor coolant system (RCS) operational leakage within 23 limits by performance of RCS water inventory balance.
24 25 Condition B specifies that if the containment sump is inoperable for reasons other than 26 Condition A, Required Action B.1 requires restoration of the containment sump to operable 27 status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or in accordance with the Risk Informed Completion Time (RICT) 28 Program. Required Action B.1 is modified by two notes which direct entering applicable 29 conditions and required actions of LCO 3.5.2, ECCS-Operating, and LCO 3.5.3, 30 ECCS-Shutdown, for ECCS trains made inoperable by the containment sump and entering 31 applicable conditions and required actions of LCO 3.6.6, Containment Spray and Cooling 32 Systems, for CSS trains made inoperable by the containment sump.
33 34 Condition C specifies that if required actions and associated completion times (CTs) under 35 Condition A and B are not met, Required Actions C.1 and C.2 require licensees to be in Mode 3 36 in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Mode 5 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />, respectively.
37 38 Traveler TSTF-567, Revision 1, proposed to expand and relocate an SR currently located in 39 LCO 3.5.2. The new SR would require licensees to verify, by visual inspection, that the 40 containment sump does not show structural damage, abnormal corrosion, or debris blockage 41 every 18 months or in accordance with the SFCP.
42 43 Some plant designs have more than one containment sump. The new containment sump LCO 44 proposed in TSTF-567, Revision 1, is also applicable to plants that have more than one 45 containment sump.
46 47 Traveler TSTF-567, Revision 1, also proposed a conforming change to the STSs Table of 48 Contents to reflect the addition of the new containment sump LCO.
49 50 This change is evaluated in Section 3.4 of this SE.
51 1
2.3 APPLICABLE REGULATORY REQUIREMENTS AND GUIDANCE 2
3 Section IV, The Commission Policy, of the Final Policy Statement on Technical Specifications 4
Improvements for Nuclear Power Reactors, published in the Federal Register on July 22, 1993 5
(58 FR 39132), states, in part:
6 7
The purpose of Technical Specifications is to impose those 8
conditions or limitations upon reactor operation necessary to 9
obviate the possibility of an abnormal situation or event giving rise 10 to an immediate threat to the public health and safety by 11 identifying those features that are of controlling importance to 12 safety and establishing on them certain conditions of operation 13 which cannot be changed without prior Commission approval.
14 15
[T]he Commission will also entertain requests to adopt portions 16 of the improved STS [(e.g., TSTF-567)], even if the licensee does 17 not adopt all STS improvements. The Commission encourages 18 all licensees who submit Technical Specification related submittals 19 based on this Policy Statement to emphasize human factors 20 principles.
21 22 In accordance with this Policy Statement, improved STS have 23 been developed and will be maintained for each NSSS [nuclear 24 steam supply system] owners group. The Commission 25 encourages licensees to use the improved STS as the basis for 26 plant-specific Technical Specifications. [I]t is the Commission 27 intent that the wording and Bases of the improved STS be used 28 to the extent practicable.
29 30 As described in the Commissions Final Policy Statement on Technical Specifications 31 Improvements for Nuclear Power Reactors, NRC and industry task groups for new STSs 32 recommended that improvements include greater emphasis on human factors principles in order 33 to add clarity and understanding to the text of the STS, and provide improvements to the Bases 34 of STS, which provides the purpose for each requirement in the specification. The improved 35 vendor-specific STS were developed and issued by the NRC in September 1992.
36 37 The regulation at 10 CFR 50.36(b) requires:
38 39 Each license authorizing operation of a utilization facility will 40 include technical specifications. The technical specifications will 41 be derived from the analyses and evaluation included in the safety 42 analysis report, and amendments thereto, submitted pursuant to 43
[10 CFR] 50.34 [Contents of applications; technical information].
44 The Commission may include such additional technical 45 specifications as the Commission finds appropriate.
46 47 The categories of items required to be in the TSs are provided in 10 CFR 50.36(c). As required 48 by 10 CFR 50.36(c)(2)(i), the TSs will include LCOs, which are the lowest functional capability 49 or performance levels of equipment required for safe operation of the facility. Per 50 10 CFR 50.36(c)(2)(i), when an LCO of a nuclear reactor is not met, the licensee shall shut 51 down the reactor or follow any remedial action permitted by the TSs until the condition can be 1
met.
2 3
The regulation at 10 CFR 50.36(c)(3) requires TSs to include SRs, which are requirements 4
relating to test, calibration, or inspection to assure that the necessary quality of systems and 5
components is maintained, that facility operation will be within safety limits, and that the LCOs 6
will be met.
7 8
The regulation at 10 CFR 50.36(c)(5) requires TSs to include administrative controls, which are 9
the provisions relating to organization and management, procedures, recordkeeping, review and 10 audit, and reporting necessary to assure operation of the facility in a safe manner.
11 12 The NRC staffs guidance for the review of TSs is in Chapter 16.0, Technical Specifications, of 13 NUREG-0800, Revision 3, Standard Review Plan for the Review of Safety Analysis Reports for 14 Nuclear Power Plants (SRP), March 2010 (ADAMS Accession No. ML100351425). As 15 described therein, as part of the regulatory standardization effort, the NRC staff has prepared 16 STSs for each of the light-water reactor nuclear designs. Accordingly, the NRC staffs review 17 includes consideration of whether the proposed changes are consistent with the applicable 18 reference STSs (i.e., the current STSs), as modified by NRC-approved Travelers. In addition, 19 the guidance states that comparing the change to previous STSs can help clarify the TS intent.
20 21
3.0 TECHNICAL EVALUATION
22 23 During the review of TSTF-567, Revision 1, the NRC staff considered generally the guidance on 24 acceptance criteria of the SRP sections described in Section 2.3 of this SE and, in particular, 25 the acceptance criteria in Chapter 16.0, Technical Specifications, of NUREG-0800, Revision 3.
26 Additionally, the NRC staff evaluated the proposed changes to the STS against what is required 27 to be in the TS under 10 CFR 50.36(c).
28 29
3.1 PROPOSED CHANGE
S TO LCO 3.5.2, ECCS-OPERATING 30 31 In TSTF-567, Revision 1, the TSTF proposed to modify and move SR 3.5.2.9 (B&W); SR 3.5.2.8 32 (W), and SR 3.5.2.10 (CE) from LCO 3.5.2 to the new containment sump LCO. The new SR 33 does not limit the visual inspection to the suction inlet, trash racks, and screens as currently 34 required by the STSs, but instead requires inspection of the entire containment sump system.
35 Traveler TSTF-567, Revision 1, describes the containment sump as consisting of the 36 containment drainage flow paths, any design features upstream of the containment sump that 37 are credited in the containment debris analysis, the containment sump strainers (or screens),
38 the pump suction trash racks, and the inlet to the ECCS and CSS piping.
39 40 The NRC staff concludes the proposed change is acceptable since the existing requirements 41 are either unchanged or expanded and continue to ensure the containment sump is unrestricted 42 (i.e., unobstructed) and stays in proper operating condition. The proposed change meets the 43 requirements of 10 CFR 50.36(c)(3) because it provides SRs to assure the necessary quality of 44 systems and components are maintained, that facility operation will be within safety limits, and 45 that the LCOs will be met.
46 47
3.2 PROPOSED CHANGE
S TO LCO 3.5.3, ECCS-SHUTDOWN 48 49 In TSTF-567, Revision 1, the TSTF proposed to delete the reference to relocated SRs (as well 50 as SR 3.5.2.9 (B&W), SR 3.5.2.8 (W), and SR 3.5.2.10 (CE)) in SR 3.5.3.1.
51 1
The NRC staff concludes the proposed change is acceptable since the SRs (B&W SR 3.5.2.9, 2
W SR 3.5.2, and CE SR 3.5.2.10) were modified and relocated to the new containment sump 3
LCO. The existing SR on the containment sump is augmented (by requiring inspection of 4
additional sump components) and moved to the new specification, and a duplicative 5
requirement to perform the SR in TS 3.5.3 is removed. The new specification retains or 6
expands existing requirements on the containment sump and the actions to be taken when the 7
containment sump is inoperable with the exception of adding new actions to be taken when the 8
containment sump is inoperable due to containment accident generated and transported debris 9
exceeding the analyzed limits. The new action provides time to evaluate and correct the 10 condition instead of requiring an immediate plant shutdown. The proposed change meets the 11 requirements of 10 CFR 50.36(c)(3) because it provides SRs to assure the necessary quality of 12 systems and components are maintained, that facility operation will be within safety limits, and 13 that the LCOs will be met.
14 15
3.3 PROPOSED CHANGE
S TO SECTION 5.5.15, SAFETY FUNCTION 16 DETERMINATION PROGRAM (SFDP) 17 18 STS LCO 3.0.6 states:
19 20 When a supported system LCO is not met solely due to a support 21 system LCO not being met, the Conditions and Required Actions 22 associated with this supported system are not required to be 23 entered. Only the support system LCO ACTIONS are required to 24 be entered. This is an exception to LCO 3.0.2 for the supported 25 system. In this event, an evaluation shall be performed in 26 accordance with Specification 5.5.15, Safety Function 27 Determination Program (SFDP). If a loss of safety function is 28 determined to exist by this program, the appropriate Conditions 29 and Required Actions of the LCO in which the loss of safety 30 function exists are required to be entered.
31 32 When a support systems Required Action directs a supported 33 system to be declared inoperable or directs entry into Conditions 34 and Required Actions for a supported system, the applicable 35 Conditions and Required Actions shall be entered in accordance 36 with LCO 3.0.2.
37 38 When a loss of safety function is determined to exist, the SFDP requires entry into the 39 appropriate conditions and required actions of the LCO in which the loss of safety function 40 exists. Where a loss of function is solely due to a single TS support system (e.g., a single 41 containment sump train), the appropriate LCO is the LCO for that support system. When the 42 loss of function is the result of multiple support systems, the appropriate LCO is the LCO for the 43 supported systems.
44 45 Traveler TSTF-567, Revision 1, proposed to add the following statement to STS 5.5.12, [W]hen 46 a loss of safety function is caused by the inoperability of a single Technical Specification support 47 system, the appropriate Conditions and Required Actions to enter are those of the support 48 system.
49 50 The NRC staff finds that the proposed addition to STS 5.5.12 clarifies the intent of the allowance 1
(not to enter Conditions and Required Actions) provided by LCO 3.0.6 and the SFDP for 2
single-train support systems. The NRC staff concludes the proposed change is acceptable 3
because the actions for the support system LCO adequately address the inoperability of that 4
system. Therefore, as required by 10 CFR 50.36(c)(5), it continues to provide adequate 5
administrative controls to assure safe operation.
6 7
3.4 PROPOSED ADDITION OF CONTAINMENT SUMP LCO 8
9 3.4.1 Considerations of the LCO 10 11 Traveler TSTF-567, Revision 1, proposed to add a new LCO to address operability 12 requirements of the containment sump. The numbering for this new LCO is as follows:
13 LCO 3.6.8 for B&W, LCO 3.6.19 for W, and LCO 3.6.13 for CE. The new LCO is also applicable 14 to plants that have more than one containment sump, because the multiple sumps are 15 considered to be part of a single support system. If containment accident generated and 16 transported debris would render one sump inoperable, then it would render all of the sumps 17 inoperable.
18 19 The containment sump supports the post-accident operation of the ECCS and CSS. However, 20 only the current ECCS LCOs contain SRs related to the containment sump and the STSs do not 21 specify required actions that specifically address an inoperable containment sump. If the 22 containment sump were found to be inoperable, as an ECCS and CSS support system, those 23 respective LCOs would not be met. In order to address concerns related to containment sump 24 operability due to debris accumulation described in GSI-191, Assessment of Debris 25 Accumulation on Pressurized-Water Reactor Sump Performance, TSTF-567, Revision 1, 26 proposed to add a new specification to address containment sump inoperability and create a 27 condition for when the sump is inoperable due to analyzed containment accident generated and 28 transported debris.
29 30 Based on the above evaluation, the NRC staff determined that proposed LCO satisfies the 31 requirements of 10 CFR 50.36(c)(2)(i) because the LCO specifies the lowest functional 32 capability or performance levels of equipment required for safe operation of the facility.
33 34 3.4.2 Considerations of the Applicability 35 36 The new LCO requires the containment sump to be operable during Modes 1, 2, 3, and 4. The 37 ECCS and CSS LCOs currently in the STSs are applicable during Modes 1, 2, 3, and 4.
38 39 The NRC staff finds the proposed applicability is acceptable because the applicability is 40 consistent with the applicability of the ECCS and CSS LCOs, the containment sump supported 41 systems.
42 43 3.4.3 Considerations of Condition A 44 45 Licensees have analyzed the susceptibility of the ECCS and CSS to the adverse effects of 46 post-accident debris blockage and operation with debris-laden fluids. Most licensees have 47 established Final Safety Analysis Report (FSAR) limits on the allowable quantities of 48 containment accident generated debris that could be transported to the containment sump 49 based on their current plant configuration. In the current STS, if unanalyzed debris sources are 50 discovered inside containment, if errors are discovered in debris-related analyses, or if a 51 previously unevaluated phenomenon that can affect containment sump performance is 1
discovered, the containment sump, and the supported ECCS and CSS, may be inoperable and 2
STS require an immediate plant shutdown with no time provided to evaluate the condition.
3 4
In order to address this situation and to provide sufficient time to evaluate the condition, 5
TSTF-567, Revision 1, proposed Condition A, which is applicable when the containment sump 6
is inoperable due to containment accident generated and transported debris exceeding the 7
analyzed limits. Under Condition A, the operability of the containment sump with respect to 8
debris is based on a quantity of debris identified and evaluated by the licensee to be acceptable.
9 Emergent nonconforming or degraded conditions affecting the quantity of analyzed debris shall 10 be evaluated using a deterministic process.
11 12 Under Condition A, Required Action A.1 mandates immediate action to be initiated to mitigate 13 the condition. Revision 1 of TSTF-567 provided the following examples of mitigating actions:
14 15 Removing the debris source from containment or 16 preventing the debris from being transported to the 17 containment sump; 18 19 Evaluating the debris source against the assumptions in 20 the analysis; 21 22 Deferring maintenance that would affect availability of the 23 affected systems and other LOCA-mitigating equipment; 24 25 Deferring maintenance that would affect availability of 26 primary defense-in-depth systems, such as containment 27 coolers; 28 29 Briefing operators on LOCA debris management actions; 30 or 31 32 Applying an alternative method to establish new limits.
33 34 The NRC staff finds the proposed Required Action A.1 and its CT are acceptable because they 35 place urgency on the appropriate actions that could mitigate or reduce the impact of the 36 identified conditions.
37 38 Concurrently, Required Action A.2 mandates SR 3.4.13.1, the RCS water inventory balance, to 39 be performed at an increased frequency of once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. An unexpected increase in RCS 40 leakage could be indicative of an increased potential for an RCS pipe break, which could result 41 in debris being generated and transported to the containment sump.
42 43 The NRC staff finds the proposed Required Action A.2 and its CT are acceptable because the 44 more frequent monitoring allows operators to act in a timely fashion to minimize the potential for 45 an RCS pipe break while the containment sump is inoperable.
46 47 In addition, Required Action A.3 requires the inoperable containment sump to be restored to 48 operable status in 90 days.
49 50 The NRC staff finds the proposed Required Action A.3 and its CT are acceptable because they 1
provide a reasonable amount of time to diagnose, plan, and possibly reduce the severity of, or 2
mitigate the unanalyzed debris condition and prevent a loss of ECCS and CSS safety function.
3 In addition, 90 days is adequate given the conservatisms in the analysis and the proposed 4
compensatory actions required to be implemented immediately by Required Action A.1. Also, 5
as discussed later in this SE section, the new SR will require visual inspection of the 6
containment sump system (including the containment drainage flow paths, any design features 7
upstream of the containment sump that are credited in the containment debris analysis, the 8
containment sump strainers, the pump suction trash racks, and the inlet to the ECCS and CSS 9
piping) for evidence of structural degradation, potential for debris bypass, and presence of 10 corrosion or debris blockage, to ensure no loose debris is present and there is no evidence of 11 structural distress or abnormal corrosion.
12 13 For plants that have more than one containment sump, the sumps are considered part of a 14 single support system because containment accident generated and transported debris issues 15 that would render one sump inoperable would render all of the sumps inoperable. The NRC 16 staff finds this proposed change is acceptable since it is a conservative assumption. Plants with 17 separate sumps are generally designed so that one sump will remain operable with the 18 design-basis debris load. The second sump is assumed to be out of service due to a single 19 failure in the ECCS or CSS. The single sump in a plant with multiple sumps is equivalent to the 20 sump in a plant with only one sump because the multiple sumps are considered to be part of a 21 single support system. If containment accident generated and transported debris were to 22 render one sump inoperable, then it would render all of the sumps inoperable. In any case 23 where the single failure did not occur, the second sump would be in service and provide 24 significant additional surface area for debris to collect, thus reducing the severity of the effects 25 of the debris. The second sump provides redundancy in these cases.
26 27 3.4.4 Considerations of Condition B 28 29 Condition B specifies the required actions for when the containment sump is inoperable for 30 reasons other than containment accident generated and transported debris exceeding the 31 analyzed limits.
32 33 Required Action B.1 requires restoring the containment sump to operable status and is modified 34 by two notes. These two notes direct entry into the conditions and required actions for the 35 supported systems (ECCS and CSS). Since Required Action B.1 directs entry to the 36 corresponding ECCS and CSS LCOs, these notes retain the existing TS actions for ECCS or 37 CSS trains made inoperable by a containment sump inoperable for reasons other than 38 containment accident generated and transported debris exceeding the analyzed limits. The 39 proposed CT for Required Action B.1 is 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or in accordance with the RICT Program.
40 Traveler TSTF-567, Revision 1, shows these CTs in brackets to show the licensee has the 41 option to insert its plant-specific licensing bases requirement.
42 43 If a licensee has received an amendment that authorizes the adoption of TSTF-505, Provide 44 Risk-Informed Extended Completion Times - RITSTF Initiative 4B, or plant-specific RICT 45 Program and the licensee has a Risk-Informed Completion Time (RICT) Program in TS 46 Section 5.0, Administrative Controls, the licensee can propose via a license amendment 47 application the option to calculate a RICT for Required Action B.1. However, a plant-specific 48 justification, consistent with the justification provided when adopting TSTF-505 or a 49 plant-specific RICT Program, needs to be provided in the license amendment request (LAR) to 50 adopt TSTF-567, Revision 1. This SE does not approve the use of the RICT Program for 51 Required Action B.1. For the purposes of this SE, the bracketed In accordance with the Risk 1
Informed Completion Time (RICT) Program, only indicates that the licensees have an 2
additional option. If a licensee chooses to use the RICT Program for Required Action B.1, its 3
LAR would not be processed as a CLIIP for adoption of TSTF-567, Revision 1, and additional 4
technical information would need to be provided to justify the use of the RICT Program for this 5
required action.
6 7
The NRC staff finds the proposed change is acceptable since it continues to provide remedial 8
actions for when the containment sump is inoperable for reasons other than Condition A and 9
ensures safe operation of the plant. In addition, the proposed CT of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> is acceptable 10 because it provides a reasonable time for repairs, and there is a low probability of an accident 11 occurring during this period necessitating the containment sump. Licensees who have received 12 an amendment authorizing the adoption of TSTF-505, Provide Risk-Informed Extended 13 Completion Times - RITSTF Initiative 4B, or plant-specific RICT Program, have the option to 14 select the RICT Program as a CT by submitting a separate license amendment request 15 supported by a plant-specific justification. The use of this traveler in combination with a RICT 16 Program is outside the scope of this SE and would be reviewed on a plant-specific basis.
17 18 3.4.5 Considerations of Condition C 19 20 If operators are unable to restore the affected containment sump to operable status under 21 Conditions A or B, Required Action C.1 requires the unit to be in Mode 3 in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> followed by 22 Mode 5 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />, as required by Required Action C.2.
23 24 The NRC staff finds the proposed condition and its required actions are acceptable because 25 they are consistent with the STS and require the operators to place the unit in a condition in 26 which the LCO no longer applies. In addition, the proposed CTs allow a reasonable amount of 27 time to reach the required plant conditions from full-power conditions in an orderly manner and 28 without challenging plant systems.
29 30 3.4.6 Considerations of the New SR 31 32 A new SR is provided in the new containment sump LCO. This SR was originally located in 33 STS LCO 3.5.2 and LCO 3.5.3. The numbering for this new SR is as follows: SR 3.6.8.1 for 34 B&W, SR 3.6.19.1 for W, and SR 3.6.13.1 for CE. The frequency of the new SR is 18 months 35 or as specified in the SFCP.
36 37 The proposed SR requires verification, by visual inspection, that the containment sump does not 38 show structural damage, abnormal corrosion, or debris blockage.
39 40 The new SR is stated in generic terms and expands the scope of the required visual inspection 41 to include the entire containment sump system. A containment sump system consists of the 42 containment drainage flow paths, the containment sump strainers (or screens), the pump 43 suction trash racks, and the inlet to the ECCS and CSS piping.
44 45 The NRC staff finds the proposed new SR is acceptable since it expands the scope of 46 inspection of the original SR. In addition, the proposed frequency is acceptable since it is the 47 same as that currently required by the STSs. Therefore, the NRC staff finds that, as required by 48 10 CFR 50.36(c)(3), the necessary quality of systems will be maintained in accordance with the 49 associated LCOs.
50 51 3.4.7 Considerations of Changes to Table of Contents 1
2 Traveler TSTF-567, Revision 1, also proposed a conforming change to the Table of Contents to 3
include the new containment sump LCO. This conforming change is acceptable since it is an 4
editorial change to support the inclusion of the new containment sump STS LCO.
5 6
3.4.8 Conclusion Regarding Proposed Containment Sump LCO 7
8 The new containment sump LCO retains and expands the existing STS requirements with the 9
exception of the addition of Condition A. Condition A provides a condition for an inoperable 10 containment sump due to containment accident generated and transported debris exceeding the 11 analyzed limits.
12 13 The NRC staff reviewed the proposed STS changes against the regulations and concludes that 14 the changes continue to meet the requirements of 10 CFR 50.36(c)(2), 50.36(c)(3), and 15 50.36(c)(5), for the reasons discussed above, and thus provide reasonable assurance that 16 plants that adopt these TSs will have the requisite requirements and controls to operate safely.
17 Therefore, the staff concludes that the proposed STS changes are acceptable.
18 19
4.0 CONCLUSION
20 21 The NRC staff reviewed Traveler TSTF-567, Revision 1, which proposed changes to 22 NUREG-1430, Volume 1, NUREG-1431, Volume 1, and NUREG-1432, Volume 1. The NRC 23 staff determined that the proposed changes to the STS meet the standards for TS in 24 10 CFR 50.36(b). Additionally, the changes to the STS were reviewed and found to be 25 technical clear and consistent with customary terminology and format in accordance with 26 SRP Chapter 16.0. The NRC staff reviewed the proposed changes against the regulations and 27 concludes that the changes continue to meet the requirements of 10 CFR 50.36(c)(2),
28 50.36(c)(3) and 50.36(c)(5), for the reasons discussed above, and thus provide reasonable 29 assurance that adoption of these TSs will have the requisite requirements and controls to 30 operate safely. Therefore, the NRC staff concludes that the proposed TS changes are 31 acceptable.
32 33 34 Principal Contributors: C. Tilton, NRR/DSS 35 S. Smith, NRR/DSS 36 P. Klein, NRR/DMLR 37 38 Date:
39