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