ML24053A102

Draft Traveler Safety Evaluation of TSTF-576, Revise Safety/Relief Valve Requirements

ML24053A102
Person / Time
Site:	Technical Specifications Task Force
Issue date:	08/01/2024
From:	Shawn Smith NRC/NRR/DSS
To:	Technical Specifications Task Force
References
EPID L -2019-PMP-0207 TSTF-576, Rev 3
Download: ML24053A102 (1)

Text

DRAFT SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION 1

TECHNICAL SPECIFICATIONS TASK FORCE TRAVELER 2

TSTF-576, REVISION 3 3

REVISE SAFETY/RELIEF VALVE REQUIREMENTS 4

(EPID L-2019-PMP-0207) 5 6

1.0 INTRODUCTION

7 8

By letter dated September 13, 2023 (Agencywide Documents Access and Management System 9

(ADAMS) Accession No. ML23256A266), the Technical Specifications Task Force (TSTF) 10 submitted Traveler TSTF-576, Revision 3, Revise Safety/Relief Valve Requirements 11 (TSTF-576), to the U.S. Nuclear Regulatory Commission (NRC). TSTF-576 proposed changes 12 to the Standard Technical Specifications (STSs) for boiling-water reactor (BWR) designs under 13 the consolidated line item improvement process (CLIIP). Upon approval, these changes would 14 be incorporated into future revisions of:

15 16 U.S. Nuclear Regulatory Commission, Standard Technical Specifications, General 17 Electric BWR/4 Plants, NUREG-1433, Volume 1, Specifications, and Volume 2, 18 Bases, Revision 5, September 2021 (ML21272A357 and ML21272A358, respectively)1.

19 20 U.S. Nuclear Regulatory Commission, Standard Technical Specifications, General 21 Electric BWR/6 Plants, NUREG-1434, Volume 1, Specifications, and Volume 2, 22 Bases, Revision 5, September 2021 (ML21271A582 and ML21271A596, respectively).

23 24 The proposed changes would revise the STSs and STS Bases related to the Safety/Relief 25 Valves (S/RVs). The approach to S/RV requirements would change from being based on 26 individual S/RVs to being based on the S/RVs being treated in STS as a single system called 27 the Overpressure Protection System (OPS). The STSs related to the S/RVs would be rewritten 28 to focus on the performance of the system instead of focusing on the performance of individual 29 valves. Instead of having the STS specify a minimum number of S/RVs capable of performing 30 their safety function, the capability of performing the safety function would be assessed from the 31 collective capability of the S/RVs. A single valve or even multiple valves lifting outside the limits 32 currently defined in STS would not necessarily result in the OPS being inoperable. The as-left 33 setting tolerances are not changing and continue to require each required valve to be set to 34 within one percent of its setpoint. The as-found upper limits would be moved to the Core 35 Operating Limits Report (COLR) and placed under licensee control. The as-found lower limits 36 are being removed from the TS. While the NRC staff has approved license amendments for 37 increases to tolerances from +/-1% to +/-3%, TSTF-576 would allow larger tolerances to be 38 implemented.

39 40 STS surveillance requirements (SR) 3.4.3.2 (NUREG-1433) and 3.4.4.3 (NUREG-1434) would 41 be met as long as the as-found opening pressures of the S/RVs are within the COLR criteria 42 1 NUREG-1433 is based on the BWR/4 plant design, but is also representative of the BWR/2, BWR/3, and, in this traveler, BWR/5 designs.

that ensure that the overpressure analysis remains valid considering the performance of the 1

total population of S/RVs. Although the COLR STS requires the licensees to perform setpoint 2

limit calculations using the methods specified in the COLR, the COLR STS does not directly 3

control the need to seek prior NRC approval of changes to associated calculations and analyses 4

that use the S/RV settings and limits as inputs; the existing requirements in Title 10 of the Code 5

of Federal Regulations (10 CFR) Section 50.59 control when a licensee is required to seek prior 6

NRC approval via a license amendment request (LAR) of those associated calculations.

7 Licensees would use 10 CFR 50.59 to evaluate their authority to make changes to those other 8

analyses without seeking prior NRC approval.

9 10 Additional background on the topic of S/RVs and recommendations for licensees has been 11 documented by staff in ADAMS at ML24204A271. The proposed TSTF included several 12 statements that while immaterial to the safety evaluation warranted written discussion by the 13 NRC staff. Licensees adopting the traveler should review the information in the referenced 14 document to ensure an efficient change to the proposed TS and help to prevent future 15 regulatory action.

16 17

1.1 Background

18 19 NUREG-1433 and NUREG-1434 STS Bases for B 2.1.2 Reactor Coolant System (RCS) 20 Pressure Safety Limit (SL) explain that the RCS S/RVs and the Reactor Protection System 21 Reactor Vessel Steam Dome Pressure - High Function have settings established to ensure that 22 the RCS pressure SL will not be exceeded. NUREG-1433 Bases STS B 3.4.4 and NUREG-23 1433 Bases STS 3.4.3 Safety/Relief Valves (S/RVs)" explains that the S/RV setpoints are 24 established to ensure the American Society of Mechanical Engineers (ASME) Boiler and 25 Pressure Vessel Code (BPV Code) limit on peak reactor pressure is satisfied. Further the STS 26 Bases explain that the ASME BPV Code specifications require the lowest safety valve be set at 27 or below vessel design pressure and the highest safety valve be set so the total accumulated 28 pressure does not exceed 110% of the design pressure for conditions, and that the transient 29 evaluations in the relevant Section of the Final Safety Analysis Report (FSAR) are based on 30 these setpoints, but also include the additional uncertainties of +/-1% of the nominal setpoint to 31 account for potential setpoint drift to provide an added degree of conservatism. NUREG-1433 32 Bases B 3.4.3 Safety/Relief Valves (S/RVs) likewise explains that the S/RV setpoints are 33 established to ensure that the ASME BPV Code limit on peak reactor pressure is satisfied, and 34 likewise notes that the transient evaluations in the FSAR are based on these setpoints, but also 35 include the additional uncertainties of +/-1% of the nominal setpoint drift to provide an added 36 degree of conservatism.

37 38 S/RVs installed in BWRs have, at times, lifted outside the allowable as-found technical 39 specification (TS) limits. Industry has made design modifications to the S/RVs to correct the 40 issue, but valves continue to experience this issue. Most plants have increased the as-found 41 tolerances for the valves from +/-1 percent to +/-3 percent. Even with the increased allowable 42 tolerances, some valves continue to lift outside the TS limits. The issue resulted in many 43 Licensee Event Reports (LERs) submitted pursuant to 10 CFR 50.73, wherein the licensees 44 conclusion was that the RCS SL for pressure would not have been challenged during design 45 basis events. The system-oriented OPS approach in TSTF-576 would eliminate the situation 46 where an S/RV being outside of the existing as-found setting limits would always result in an 47 inoperability and an LER. For the reasons explained below, the OPS approach provides the 48 requisite reasonable assurance of public health and safety and reasonable assurance of 49 meeting the Commissions regulations, and therefore TSTF-576 is approved for incorporation 50 into the future versions of the STS and associated Bases.

51

2.0 REGULATORY EVALUATION

1 2

2.1 Safety/Relief Valve Description 3

4 The S/RVs function to protect the reactor coolant pressure boundary (RCPB) and its associated 5

SL from overpressure. In addition, some S/RVs are also used to provide the Low-Low Set relief 6

function and the Automatic Depressurization System (ADS) function. The LLS relief function is 7

specified in limiting condition for operation (LCO) 3.6.1.6 Low-Low Set (LLS) Valves and the 8

ADS function is specified in LCO 3.5.1 ECCS [emergency core cooling system]-Operating.

9 The associated ADS and LLS LCOs are not affected by the proposed changes.

10 11 STS Section 2.0 specifies the SL requirements for each reactor design. STS 2.1.2, Reactor 12 Coolant System Pressure SL, for both the NUREG-1433 and NUREG-1434 STS requires 13 reactor steam dome pressure to remain less than or equal to 1325 pounds per square inch 14 gauge (psig). The SL pressure may be different for different plants. The SL is consistent with the 15 ASME BPV Code,Section III limit of 110 percent of design pressure. Per 10 CFR 50.54, the 16 applicable requirements of 10 CFR 50.55a, are conditions in every nuclear power reactor 17 operating license issued under 10 CFR Part 50, and, as specified in 10 CFR 50.55a(b), systems 18 and components of boiling and pressurized water-cooled nuclear power reactors must meet the 19 requirements of the ASME BPV Code and the ASME Operation and Maintenance (OM) Code.

20 The ASME BPV Code provides overpressure protection requirements for the RCPB 21 components to assure that they will not be damaged during possible transients.

22 23 Some plants rely only on the safety mode of operation to protect the SL while other plants rely 24 on both the safety and relief modes of operation. In the safety mode (or spring mode of 25 operation), the spring-loaded disk or pilot valve opens when steam pressure overcomes the 26 spring force holding the valve or pilot valve closed. In the relief mode of operation, pneumatic 27 pressure is used to open the valve, initiated by switches located in the control room or by 28 pressure-sensing instrumentation.

29 30 2.2 Proposed Changes to the Standard Technical Specifications 31 32 Proposed changes applicable to both NUREG-1433 (BWR/4 plants) and NUREG-1434 (BWR/6 33 plants) for STS 3.4.3 and 3.4.4, respectively:

34 35 The name of the STS Section would be renamed from Safety/Relief Valves (S/RVs) to 36 Overpressure Protection System (OPS).

37 38 The LCO would be revised from requiring a specified number of S/RVs to be operable to 39 The OPS shall be OPERABLE. For NUREG-1434, the requirement for the relief 40 function of a specific number of S/RVs to have their relief function operable is also 41 deleted.

42 43 Conditions A, B, and C under Actions would be deleted. A new Condition A would state 44 OPS inoperable. The Required Action for entering proposed Condition A would be: be 45 in MODE 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and MODE 4 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The Action and Completion Time for 46 the proposed Condition A are the same as those in the existing Condition C.

47 48 SRs 3.4.3.1 (NUREG-1433) and 3.4.4.1 (NUREG-1434) would be revised to delete a 49 note that allows up to two S/RVs to be changed to a lower setpoint group. The as-found 50 relief limits would be deleted from the SR resulting in the SR simply requiring that the as-1 left S/RV settings be within one percent of the valves nominal setpoints. For the 2

frequency of this SR, the option for a calendar frequency or use of the Surveillance 3

Frequency Control Program (SFCP) would be deleted. The frequency is proposed as In 4

accordance with the INSERVICE TESTING PROGRAM.

5 6

For NUREG-1433 for BWR/4 plants:

7 8

SR 3.4.3.2 is proposed to be revised to state, Verify the as-found OPS lift pressures of 9

the [required] S/RVs are within the limits specified in the COLR. In addition to moving 10 the limits to the COLR, the traveler removes the lower as-found tolerance. The 11 frequency for the SR would be In accordance with the INSERVICE TESTING 12 PROGRAM. The existing SR 3.4.3.2 that required each S/RV be verified to be capable 13 of opening when manually actuated would be deleted. The note that allows the SR to be 14 performed up to 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after reactor steam pressure and flow are adequate to perform 15 the test would also be deleted. The existing frequency based on calendar time or the 16 SFCP would be deleted.

17 18 For NUREG-1434 for BWR/6 plants:

19 20 SR 3.4.4.2 would be revised to state, Verify each S/RV [required] to act in the relief 21 mode actuates on an actual or simulated automatic initiation signal. This would be a 22 change in nomenclature with no real effect on the requirement. The frequency remains 23 at [18] months or per the SFCP.

24 SR 3.4.4.3 is proposed to be replaced in its entirety. The requirement to verify that each 25 S/RV opens when manually actuated would be deleted and would be replaced with, 26 Verify the as-found OPS lift pressures of the [required] S/RVs are within the limits 27 specified in the COLR. In addition to moving the limits to the COLR, the traveler 28 removes the lower as-found tolerance. The proposed frequency for the SR is In 29 accordance with the INSERVICE TESTING PROGRAM. The existing frequency based 30 on calendar time or the SFCP would be deleted.

31 32 Last, the COLR STS 5.6.3 in both NUREGs would not be changed.

33 34 2.3 Applicable Regulatory Requirements and Guidance 35 36 As described in the Commissions Final Policy Statement on Technical Specifications 37 Improvements for Nuclear Power Reactors (Final Policy Statement) (58 FR 39132, dated 38 July 22, 1993), the NRC and industry task groups for new STSs recommended that 39 improvements include greater emphasis on human factors principles in order to add clarity and 40 understanding to the text of the STSs, and provide improvements to the STS Bases, which 41 provide the purpose for each requirement in the STSs. The improved vendor-specific STSs 42 were developed and issued by the NRC in September 1992.

43 44 Both the common standards for licenses in 10 CFR 50.40(a) (regarding, among other things, 45 consideration of the operating procedures, the facility and equipment, the use of the facility, and 46 other technical specifications, or the proposals) and those specifically for issuance of operating 47 licenses in 10 CFR 50.57(a)(3), provide that there must be reasonable assurance that the 48 activities at issue will not endanger the health and safety of the public and that the applicant will 49 comply with the Commission's regulations. The regulations in paragraph 50.36(a)(1) require 50 that:

51 1

Each applicant for a license authorizing operation of a production or utilization 2

facility shall include in his application proposed technical specifications in 3

accordance with the requirements of this Section. A summary statement of the 4

bases or reasons for such specifications, other than those covering 5

administrative controls, shall also be included in the application, but shall not 6

become part of the technical specifications.

7 8

The Commissions Final Policy Statement at 58 FR 39138 states that each LCO, action, and SR 9

should have supporting Bases, and the Bases should at a minimum address certain questions 10 and cite references to appropriate licensing documentation (e.g., FSAR, Topical Report) to 11 support the Bases. Those questions are listed in the relevant sections below.

12 13 The regulations in 10 CFR 50.36(b) require that:

14 15 Each license authorizing operation of a production or utilization facility will 16 include technical specifications. The technical specifications will be derived from 17 the analyses and evaluation included in the safety analysis report, and 18 amendments thereto, submitted pursuant to [10 CFR] 50.34 [Contents of 19 applications; technical information]. The Commission may include such 20 additional technical specifications as the Commission finds appropriate.

21 22 Per 10 CFR 50.36(c)(1), (2), (3), and (5), TS will include items in, among other things, the 23 categories of SLs, limiting conditions for operation, SRs, and administrative controls, 24 respectively. Details about these categories are discussed below.

25 26 Safety limits are addressed by 10 CFR 50.36(c)(1)(i)(A), which states in part:

27 28 Safety limits for nuclear reactors are limits upon important process variables that 29 are found to be necessary to reasonably protect the integrity of certain physical 30 barriers that guard against the uncontrolled release of radioactivity. If any safety 31 limit is exceeded, the reactor must be shut down.

32 33 Limiting conditions for operation are addressed by 10 CFR 50.36(c)(2), and 10 CFR 34 50.36(c)(2)(i) states:

35 36 Limiting conditions for operation are the lowest functional capability or 37 performance levels of equipment required for safe operation of the facility. When 38 a limiting condition for operation of a nuclear reactor is not met, the licensee shall 39 shut down the reactor or follow any remedial action permitted by the technical 40 specifications until the condition can be met.

41 42 The remedial actions permitted by the TS must provide the requisite reasonable assurance 43 required by 10 CFR 50.40(a) and 50.57(a)(3). In its Final Policy Statement at 58 FR 39138, the 44 Commission stated that the Bases for each LCO, should explain why the LCO was determined 45 to be the lowest functional capability or performance level for the system or component in 46 question necessary for safe operation of the facility and, what are the reasons for the 47 Applicability of the LCO.

48 49 The regulations in 10 CFR 50.36(c)(2)(ii)(A)-(D) list the criteria for determining when an LCO of 50 a nuclear reactor must be established. Note that per 10 CFR 50.36(c)(2)(iii), a licensee is not 51 required to propose to modify technical specifications that are included in any license issued 1

before August 18, 1995, to satisfy the criteria in 10 CFR 50.36(c)(2)(ii). In its Final Policy 2

Statement at 58 FR 39138, the Commission stated that the Bases should provide the 3

justification for the technical specification, i.e., which Policy Statement criterion requires it to be 4

in the technical specifications.

5 6

Criterion 3 from 10 CFR 50.36(c)(2)(ii)(C) requires the establishment of an LCO for a structure, 7

system, or component that is part of the primary success path and which functions or actuates 8

to mitigate a design basis accident or transient that either assumes the failure of or presents a 9

challenge to the integrity of a fission product barrier.

10 11 SRs are addressed by 10 CFR 50.36(c)(3), and are requirements relating to test, calibration, or 12 inspection to assure that the necessary quality of systems and components is maintained, that 13 facility operation will be within safety limits, and that the limiting conditions for operation will be 14 met. In its Final Policy Statement at 58 FR 39138, the Commission stated that the Bases should 15 explain the Bases for each Surveillance Requirement and Surveillance Frequency; i.e., the 16 specific functional requirement is the surveillance designed to verify, and the reason the 17 surveillance necessary at the specified frequency to assure that the system or component 18 function is maintained, that facility operation will be within the safety limits, and that the LCO will 19 be met.

20 21 Administrative controls are addressed by 10 CFR 50.36(c)(5) and are the provisions relating to 22 organization and management, procedures, recordkeeping, review and audit, and reporting 23 necessary to assure operation of the facility in a safe manner.

24 25 As defined in STS 1.1, the COLR is the unit-specific document that provides cycle-specific 26 parameter limits for the current reload cycle. These cycle-specific limits shall be determined for 27 each reload cycle in accordance with STS 5.6.3. Core Operating Limits Report. Plant 28 operation within these limits is addressed in individual TSs. STS 5.6.3.a. requires that core 29 operating limits shall be established prior to each reload cycle, or prior to any remaining portion 30 of a reload cycle, and shall be documented in the COLR for individual specifications that 31 address core operating limits listed STS 5.6.3.a. All current BWR licenses have in their TS an 32 analogous requirement.

33 34 The regulations in 10 CFR 50.55a(c)(1) specify that components which are part of the 35 RCPB must meet the requirements for Class 1 components in Section III of the ASME BPV 36 Code, except as provided in 10 CFR 50.55a(c)(2), (3), and (4). 10 CFR 50.55a(f)(4) further 37 requires, in part, that throughout the service life of BWR facilities, valves that are within the 38 scope of the ASME OM Code must meet the inservice test requirements (except design and 39 access provisions) set forth in the ASME OM Code to the extent practical, within the limitations 40 of design, geometry, and materials of construction of the components.

41 42 The NRC staffs guidance for the review of TSs is in NUREG-0800, Standard Review Plan for 43 the Review of Safety Analysis Reports for Nuclear Power Plants: LWR [light-water reactor]

44 Edition (SRP), Chapter 16.0, Technical Specifications, Revision 3, dated March 2010 45 (ML100351425).

46 47

3.0 TECHNICAL EVALUATION

48 49 The NRC staff reviewed TSTF-576, Revision 3, which proposes changes to NUREG-1433 and 50 NUREG-1434. The NRC staff considered the requirements and guidance listed in Section 2.3 of 51 this safety evaluation (SE) in its review to determine the acceptability of the proposed changes.

1 The NRC staff reviewed the changes to determine whether the proposed revisions to the STS 2

meet the standards for TS in 10 CFR 50.36, as well as maintain consistency with the Final 3

Policy Statement. The NRC staff evaluation focused on the ability of the proposed STS changes 4

to ensure that the SL for RCS pressure would not be exceeded. The NRC staff also considered 5

whether the proposed changes could challenge the assumptions used in other plant analyses.

6 7

The NRC staff concludes that the requested changes in the traveler are acceptable for the 8

reasons discussed in this SE. The NRC staff provides the following discussion of its evaluation 9

as well as other important information related to its review of the traveler.

10 11 3.0.1 The Usage of Align in TSTF-576 Should Not Be Read as Implying That the STS Are 12 Incongruent with the Regulations and Commission Policy Statement 13 14 TSTF-576 uses language that could be read as suggesting that the current STS and current 15 issued operating licenses are not aligned with the regulations and that the current STS do not 16 meet the Commissions Policy Statement. However, the NRC staff does not read those 17 statements in that fashion. Instead, the NRC staff reads such align statements as recognitions 18 that a different approach can align with the regulations in 10 CFR 50.40, 50.57, 50.54, and 19 50.55a; acceptance of a proposed revision to the STS should not result in an inference that the 20 existing STS fail to meet regulations and fail to provide reasonable assurance. The model STS 21 on S/RVs is fully aligned with the Commissions regulations including, for example, 10 CFR 22 50.40(a) (consideration of, among other things, how the operating procedures, the facility and 23 equipment, the use of the facility, and other technical specifications, collectively provide 24 reasonable assurance that the applicant will comply with the Commissions regulations and that 25 the health and safety of the public will not be endangered). As documented in numerous 26 licensing actions, the NRC has found that proposed plant-specific TS that include LCOs, actions 27 to be taken when the LCOs cannot be met, and SRs provide the requisite reasonable assurance 28 of public health and safety and compliance with the Commissions regulations needed to 29 support issuing or amending an operating license.

30 31 3.0.2 Using a System-based LCO Instead of a Component-Based LCO is Acceptable Under 32 10 CFR 50.36(c) 33 34 The NRC staff considered how TSTF-576 changed the approach for the LCO from a 35 component-based determination to a system-based determination. The regulation at 10 CFR 36 50.36(c)(2)(i) requires that TS include items in the category of limiting conditions for operation 37 that are the lowest functional capability or performance levels of equipment required for safe 38 operation of the facility. Further, 10 CFR 50.36(c)(2)(ii)(A)-(D) sets forth four criteria to be used 39 to determine if a TS LCO must be established. Criterion 3 in 10 CFR 50.36(c)(2)(ii)(C) and 40 Criterion 4 in 10 CFR 50.36(c)(2)(ii)(D) treat a structure, system, or component equally when 41 considering the need to establish an LCO. Thus, the staff concludes that there is no prohibition 42 that would preclude changing a TS LCO from component-based to system-based. The NRC 43 staff notes that a review of LCOs in the STS clearly show that the lowest functional capability 44 may be equally well represented by component (e.g., LCOs for containment isolation valves) or 45 system (e.g., LCOs for systems like STS 3.2.1 for Average Planar Linear Heat Generation Rate) 46 level criteria, or a combination of these. Thus TSTF-576, which would make such a component-47 based to systems-based change for an LCO, is not contrary to the regulations in 10 CFR 48 50.36(c)(2).

49 50 3.0.3 10 CFR 50.59 Addresses When Prior NRC Approval Must Be Obtained Prior to 1

Implementing Changes to Analyses That Use S/RV settings.

2 3

The scope of a licensing action to adopt TSTF-576 would be defined by a LAR. An issue that 4

the staff considered during this review is the fact that if the S/RV as-found upper tolerances are 5

changed via the processes set forth in TSTF-576, then a licensee would also need to change 6

the corresponding inputs, criteria, or other considerations associated with the S/RV as-found 7

upper tolerances. Whether such changes must first be approved by the NRC via a license 8

amendment is controlled by the Commissions regulations in 10 CFR 50.59.

9 10 The traveler indicates that methods used to perform other analyses of record, such as 11 containment or S/RV piping integrity, or high-pressure injection system capability, might also be 12 affected. Licensees adopting changes to as-found S/RV limits controlled by the COLR are 13 required to evaluate the effects of changes on other analyses by 10 CFR 50.59. Analyses that 14 are directly affected by changing the allowable as-found lift pressures might include, but are not 15 limited to, S/RV tailpipe mechanical loading, containment integrity, high pressure ECCS 16 performance, and standby liquid control performance. This is not an all-inclusive list of affected 17 analyses because plants may have other analyses that use the S/RV settings as inputs, criteria, 18 or considerations. However, the licensees compliance with 10 CFR 50.59, and licensees 19 resulting to seek, or to decline to seek, prior approval via a LAR of changes to those associated 20 analyses are beyond the scope of this SE.

21 22 3.0.4 Removal of the Lower As-found Tolerance 23 24 The proposed change in TSTF-576 removes the as-found low tolerance pressure limit from the 25 STS. The low tolerance is not an assumption in the overpressure analysis and is not needed to 26 protect the overpressure SL. One purpose of the lower as-found setpoint tolerance is to ensure 27 sufficient margin exists between the normal operating pressure of the system and the point at 28 which the S/RVs actuate in the safety mode. The difference between normal operating pressure 29 and the lowest opening pressure of relief valves is referred to as the simmer margin. If the 30 opening pressure of an S/RV drifts too low, it could open during normal operation or a minor 31 transient, thus initiating a transient or increasing the consequences of a transient.

32 33 Some plants make use of the LLS function. This function is to open an S/RV earlier (i.e., at a 34 lower pressure) and stay open longer to avoid excessive short duration S/RV cycling. If the 35 opening pressure of an S/RV drifts down, that S/RV could open before reaching the LLS 36 setpoint and could then open/close repeatedly, defeating the LLS function.

37 38 The existing S/RV TS and proposed OPS TS protect the RCS from damage due to 39 overpressure. Other programs ensure that the as-found low setpoints are acceptable. For 40 example, the Inservice Testing (IST) Program will continue to confirm that the tested S/RVs 41 open between an established lower and upper tolerance about the setpoint. In addition, the 42 traveler states that the S/RVs fall under the Maintenance Rule, 10 CFR 50.65, and that licensee 43 Maintenance Rule programs require establishing performance criteria, monitoring and trending 44 performance, determining the cause of failures, and taking corrective action. Accordingly, 45 licensees are required to implement 10 CFR 50.65 considering the requirements of the rule as 46 they apply to the S/RVs, including the potential for causing unanticipated transients through 47 inadvertent S/RV opening. The IST Program assures the operational readiness of components 48 within its purview. The Maintenance Rule requires all plants to trend the performance of 49 components and systems important to safety to assure that they maintain adequate levels of 50 quality. Therefore, NRC staff concludes that these requirements are adequate to identify, 51 assess, and take corrective actions for the potential effects of low S/RV as-found setpoints on 1

plant operation.

2 3

3.0.5 Using the COLR for Controlling S/RV As-Found Limits 4

5 TSTF-576 references the COLR STS program as follows:

6 7

The COLR Specification, paragraph c, states, The core operating limits shall be 8

determined such that all applicable limits (e.g., fuel thermal mechanical limits, 9

core thermal hydraulic limits, Emergency Core Cooling Systems (ECCS) limits, 10 nuclear limits such as SDM, transient analysis limits, and accident analysis limits) 11 of the safety analysis are met. This paragraph will also apply to the S/RV as-12 found pressure limits. If a licensee should specify S/RV as-found lift pressure 13 limits that will result in an increase in the peak reactor pressure in an 14 overpressure event or a nonconservative change in the S/RV analysis-of-record 15 (e.g., thrust load), the licensee must also consider other effects resulting from the 16 new limits as required by paragraph c.

17 18 The proposed change includes removing the as-found acceptance criteria for the S/RVs from 19 the STS and moving them to the COLR. Once relocated to the COLR, the settings would be 20 controlled by the licensee and changes would no longer require a TS change, LAR, or prior 21 review and approval by the NRC. The traveler requires each licensee to reference an 22 NRC-approved method for the RCS overpressure analysis in the COLR. The COLR TS 5.6.3 23 specifies a list of NRC-approved methods from which a method must be used. The licensee 24 would use that approved method to assure that the as-found limits would adequately protect 25 RCS pressure and assure that the SL is not exceeded. Although the relocation of the S/RV as-26 found limits to the COLR is different from previous items in the COLR (i.e., it is not a cycle-27 specific core physics parameter), the NRC staff determined that under the proposed controls, 28 relocation is acceptable for the overpressure analysis because the use of an NRC-approved 29 methodology is required, as discussed in Section 3.1 of this SE.

30 31 Under the existing STS, all calculations used to develop values in the COLR are performed 32 using NRC-approved methods that are specified in the COLR. If a licensee desires to use a 33 different method than the one listed in the COLR, a change to the TS is required and the 34 licensee must submit a LAR to change the COLR in Section 5 of their TS.

35 36 The peak reactor pressure in an overpressure event must be determined in accordance with an 37 NRC-approved methodology that is specified in the COLR TS. Note that this SE does not 38 address a licensees request for approval, via a license amendment, of a method to be specified 39 in the COLR TS.

40 41 In addition to relocating the as-found allowable tolerances, TSTF-576 changes the way the 42 tolerances are applied. The existing STS SR requires each valve to open within +/-3% of its 43 setpoint. TSTF-576 does not define the formatting of the new limits or how the setpoints will be 44 specified in the COLR. However, the traveler provides examples of how the COLR limits could 45 be presented in plant-specific COLRs. As stated in TSTF-576 and shown in the examples, the 46 as-found lift pressure limits are not valve-specific. That is, the limits may be expressed as a 47 single limit for all valves, or as one or more S/RVs opening below a prescribed pressure and 48 one or more other groups of valves opening at different limits. Various combinations of as-found 49 limits may be used.

50 51 Per 10 CFR 50.73(a)(2)(i)(B), the holder of an operating license issued under 10 CFR Part 50 or 1

a combined license issued under 10 CFR Part 52 shall submit an LER within 60 days after the 2

discovery of any operation or condition that was prohibited by the plant's technical specifications 3

(with certain exceptions). Accordingly, if during testing, a licensee determines that the OPS as-4 found condition exceeds the limits established in the COLR, then the licensee would document 5

the findings in an LER that meets 10 CFR 50.73(b). The required contents of an LER are 6

provided in 10 CFR 50.73(b).

7 8

3.0.6 Testing and ASME OM Code Requirements 9

10 For as-found testing, the traveler would require that the population of S/RVs to be tested and 11 the frequency of the testing be per the ASME OM Code. The traveler states that the testing is 12 performed during a plant shutdown and verifies that each S/RV opens within the required 13 as-found tolerance around the setpoint. However, the ASME OM Code does not require every 14 S/RV to be tested each plant shutdown. ASME OM Code Mandatory Appendix I, paragraph I-15 1320, Test Frequencies, Class 1 Pressure Relief Valves, requires a minimum of 20% of the 16 valves from each valve group to be tested within any 24-month interval. Mandatory Appendix I, 17 subparagraph I-1320(c), Requirements for Testing Additional Valves, gives the process for 18 testing additional valves when a valve test acceptance criterion is not met. Specifically, it states 19 that:

20 21 additional valves shall be tested in accordance with the following requirements:

22 (1) For each valve tested for which the as-found set-pressure (first test actuation) 23 exceeds the greater of either the plus/ minus tolerance limit of the 24 Owner-established set-pressure acceptance criteria of I-1310(e) or +/-3% of valve 25 nameplate set-pressure, two additional valves shall be tested from the same 26 valve group. (2) If the as-found set-pressure of any of the additional valves tested 27 in accordance with (1) exceeds the criteria noted therein, then all remaining 28 valves of that same valve group shall be tested.

29 30 The ASME OM Code does not require each S/RV be tested at each plant shutdown, but rather 31 a minimum of 20% of the valves from each valve group within any 24-month interval, with 32 additional testing if the valve as-found setpoints are not within the required tolerance. Mandatory 33 Appendix I, subparagraph I-1310(e) Acceptance Criteria, allows the Owner to establish and 34 document acceptance criteria for tests required by Mandatory Appendix I. That is, the ASME 35 OM Code would require the values included in the COLR (or a more conservative value) be 36 used for determination of acceptable performance and whether the valve population being 37 tested needs to be expanded.

38 39 Some licensees test the valves during each refueling outage and expand the population of 40 valves to be tested during the outage, if required, based on the test results. Other licensees 41 remove the full population of valves, replace them with spares that have been set to within the 42 required as-left tolerance, and test the removed S/RVs (within a year of removal from the 43 system) after the plant is returned to service.

44 45 The traveler would allow different S/RVs to have different setpoint tolerances. If the valve testing 46 and population expansion is based on a single tolerance, then the ASME OM Code criteria for 47 requiring additional valves to be tested can be applied. If there are different tolerances for 48 different S/RVs, ASME OM Code requirements can no longer be applied. The traveler states on 49 page 15 of Section 3, that if a licensee adopts more than one IST acceptance criteria, the 50 licensee will have to request guidance, relief, or an alternative because this situation is not 51 addressed in the current ASME OM Code requirements. The Commissions regulations in 10 1

CFR 50.55a provide Required Actions for cases where IST Code requirements conflict with 2

technical specifications.

3 4

3.0.7 Usage of System-Based OPS LCO Provides Reasonable Assurance 5

6 The NRC staff evaluated the philosophical change from an S/RV (component) based TS to an 7

OPS (system) based LCO. The methods required to determine the acceptability of the as-found 8

acceptance criteria would be specified in the COLR. The as-found criteria for upper limits would 9

be moved to the COLR and could be changed by the licensee without NRC staff review. This is 10 a change from the current method which requires prior NRC approval via a license amendment 11 of S/RV as-found tolerances on a component-by-component basis. The lower tolerances are 12 controlled by the ASME OM Code as required by 10 CFR 50.55a. This allows the licensee to 13 establish limits other than the +/-3 percent specified in the ASME OM Code. Second, the upper 14 as-found setting acceptance criteria are proposed to be system-based (OPS) instead of based 15 on individual valve settings. The use of NRC staff-approved methods provides adequate 16 assurance that the values in the COLR will be acceptable.

17 18 In addition to moving the upper as-found tolerances to the COLR TS, the requirements for 19 specific numbers of valves to be operable would be deleted. The valves are reset, before 20 installation, to within +/-1 percent of the nameplate setpoints as required by the ASME OM Code 21 and the TS. The ASME OM Code requires all valves to be reset to meet the acceptance criteria 22 of the ASME OM Code and the TS specifies the required S/RVs be reset to the +/-1 percent 23 tolerance. Resetting the valves to within +/-1 percent of the nameplate setpoints and operating 24 experience provides assurance that even if the S/RVs drift, the drift will not result in a condition 25 that would result in a challenge to the RCS pressure SL during a design basis accident (DBA).

26 Operating experience shows that it is unlikely for an S/RV to become inoperable for reasons 27 other than setpoint drift, or to be discovered to be inoperable except during as-found testing.

28 The NRC staff also notes that if an S/RV was determined to be inoperable while the plant is in 29 operation, the licensee would have to perform an evaluation to show that the remaining valves 30 meet TS requirements and protect the SL, or the plant would have to be taken out of the 31 applicability for the LCO. Therefore, the NRC staff concludes that it is acceptable to replace the 32 LCO requirement for a specific number of valves to be operable with a requirement for the 33 collective ability of the S/RVs (the OPS) to be operable.

34 35 The changes to the Actions would also delete the Conditions that require action if a specific 36 number of S/RVs are inoperable. As discussed above, the ASME OM Code requires that all 37 S/RVs be operable when they are installed following maintenance. The traveler noted that the 38 Actions for a specific number of S/RVs to be inoperable, currently contained in the STS, are 39 included in a relatively small number of BWR plant TS. Based on operating experience and the 40 ASME OM Code requirements to reset all valves to the required tolerance prior to placing them 41 in service, the NRC staff concludes that it is reasonable to assume that the S/RVs are capable 42 of preventing an overpressure condition in the RCS as long as the OPS is operable as required 43 by the proposed LCO. The COLR TS will contain the required NRC-approved methods that 44 must be used to determine the specific requirements for OPS operability.

45 46 3.1 Standard Technical Specification 5.6.3, Core Operating Limits Report 47 48 The COLR was established to provide licensees the ability to control cycle-specific parameters 49 outside the TS. The COLR establishes requirements for analyses used to develop values 50 included in the COLR. Per STS 5.6.3.b, The analytical methods used to determine the core 51 operating limits shall be those previously reviewed and approved by the NRC, specifically those 1

described in the following documents [listed in TS 5.6.3.b].

2 3

The traveler states that the S/RV as-found tolerance limits will be removed from the S/RV TS 4

and the upper limits will be added to the COLR. The lower limits will be removed from TS and 5

will be established per the ASME OM Code which allows the licensee to establish limits other 6

than the +/-3 percent specified in the ASME OM Code. Refer to the discussions above in 7

Section 3.0.5, Using the COLR for Controlling S/RV As-Found Limits, for background on this 8

issue and the NRC staffs evaluation.

9 10 The NRC staff evaluated the relocation of the as-found S/RV limits to the COLR and found it 11 acceptable because:

12 The LCO requires the OPS to be operable.

13 All as-found limits, with greater tolerance than those approved in the licensees existing 14 TS, must be evaluated to assure that all analyses applicable to the plant remain valid for 15 the greater tolerance.

16 The licensee will perform the overpressure analysis using an NRC-approved 17 methodology which will be specified in the COLR specification.

18 Evaluations of other potentially affected analyses are required by the COLR TS.

19 Licensees will determine when prior NRC approval is required using the 10 CFR 50.59 20 regulation. Licensees are required to verify that methods used to evaluate these 21 analyses are consistent with those in the plant licensing basis.2 22 23 3.2 NUREG-1433 Standard Technical Specification 3.4.3, Safety/Relief Valves (S/RVs) 24 25 3.2.1 Change to the Name of STS 3.4.3 26 27 The name of STS 3.4.3 is proposed to be changed from Safety/Relief Valves (S/RVs) to 28 Overpressure Protection System (OPS). This change is proposed to clarify that the S/RVs are 29 governed by several STS, not just STS 3.4.3. The proposed STS 3.4.3 only relates to the 30 cumulative behavior of the S/RVs acting in the safety mode, and relief mode at some BWR/4 31 plants, to protect the RCS from overpressure, and is therefore proposed to be renamed to OPS.

32 The name change does not affect STS requirements, SRs, or other Required Actions, and will 33 add clarity to the proposed STS as it aligns with the OPS function. Therefore, the NRC staff 34 concludes that the proposed name change is acceptable.

35 36 3.2.2 Change to LCO 3.4.3 37 38 LCO 3.4.3 currently states, The safety function of [11] S/RVs shall be OPERABLE. The LCO is 39 proposed to be changed to, The OPS shall be OPERABLE. The controls contained in the 40 COLR specification will assure that the RCS pressure SL will not be exceeded because the 41 OPS LCO is equivalent to the existing requirement to have a specific number of S/RVs 42 operable. Individual S/RVs may have different as-left tolerances established in the COLR, but 43 the OPS will prevent the SL from being exceeded. The COLR specification requires the 44 overpressure, and other analyses that could be affected by individual valve inoperability or 45 changes to COLR values, to be evaluated by the licensee. The NRC staffs evaluation of this 46 2 In the past, evaluations for expanding S/RV as-found tolerances were conducted using guidance from General Electric TR NEDC-31753P, BWROG In-Service Pressure Relief Technical Specification Revision Licensing Topical Report, February 1990.

change is discussed in Section 3.0.5 of this SE. The NRC staff finds that the change is 1

acceptable because the requirements within the revised STS 3.4.3 will ensure that the S/RVs 2

are capable of providing the overpressure protection required for the RCS.

3 4

3.2.3 Changes to Conditions and Required Actions in LCO 3.4.3 5

6 The existing action associated with Condition A of LCO 3.4.3 requires if one or two required 7

S/RVs are inoperable that they be restored to OPERABLE status in 14 days or per the Risk 8

Informed Completion Time (RICT) Program. Existing Condition B requires if the Required Action 9

of Condition A is not met, that the plant be in Mode 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. Existing Condition C requires 10 that if three or more required S/RVs are inoperable that the plant be in Mode 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and 11 Mode 4 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. Conditions A, B, and C of this Action would be deleted.

12 13 The note associated with Required Action B.1, which states that LCO 3.0.4.a is not applicable 14 when entering Mode 3, would be deleted as part of the elimination of the Action. The note is no 15 longer required because the new Condition A, described below, has a terminal action to be in 16 Mode 4, which is outside the applicability of the LCO.

17 18 A new Condition A is proposed that reads, OPS inoperable. In this condition, the Required 19 Actions are to be in Mode 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and Mode 4 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The traveler contains no 20 further Conditions or Actions.

21 22 While the overall reliability of the system is reduced when S/RVs are inoperable, individual 23 valves being inoperable may not prevent the ability of the system to perform its safety function.

24 If a licensee determines that one or more S/RVs is inoperable it would have to determine if the 25 individual valve inoperability results in an OPS inoperability. In addition, the action requirements 26 and completion times for an inoperable OPS are the same as those currently in place for 27 conditions where S/RVs might be incapable of adequately limiting RCS pressure during 28 postulated events.

29 30 3.2.4 Changes to Surveillance Requirements 3.4.3.1 and 3.4.3.2 31 32 SR 3.4.3.1 is proposed to be revised to read, Verify the as-left OPS lift pressures of the 33

[required] safety/relief valves (S/RVs) are within +/-1% of the nominal setpoint. The proposed 34 frequency would be in accordance with the IST Program. The proposed SR also lists the 35 number of S/RVs in each setpoint group and the nominal setpoints for each group. The traveler 36 removes the requirement to verify the as-found setpoints from SR 3.4.3.1 and relocates it to the 37 revised SR 3.4.3.2. The as-found upper limits are moved to the COLR, and the as-found lower 38 limits are established per the ASME OM Code. The traveler deletes an optional note that allows 39 up to two S/RVs to be moved to a lower group. The elimination of the note is acceptable 40 because only one plant in the BWR fleet has this note in its TS so it should not be included in 41 the STS. The note also provided additional flexibility, so removing it is conservative. The 42 proposed change would also delete the alternate frequencies of [18] months and in accordance 43 with the SFCP. The proposed change simplifies the SR by using the requirements of the ASME 44 OM Code for the as-left setting frequencies and eliminates unnecessary language. The 45 requirement of the proposed SR 3.4.3.1 to set the S/RVs to within +/-1% of the nominal setpoint 46 helps to provide an expectation of operability for the valves throughout the operating cycle 47 considering the historical drift associated with as-found testing. The SR is reworded in terms of 48 the OPS. The elimination of the alternative frequencies is acceptable because the IST Program 49 frequency requirements are adequate to assure that the valves have as-left settings that 50 maintain adequate safety. The frequencies for testing specified in the OM Code provide 1

adequate assurance that the S/RV testing assure operational readiness.

2 3

The existing SR 3.4.3.23, which requires verification that each [required] S/RV opens when 4

manually actuated, would be deleted. The traveler states that the TS of only seven of the 5

30 units include an equivalent SR. The traveler also states that plant safety analyses do not 6

assume that the S/RVs will open manually to limit overpressure and, as a result, the ability to 7

open manually is not required to demonstrate that the valve can perform its specified safety 8

function. The NRC staff concludes that it is not necessary to test the manual actuation function if 9

this function is not credited in the plant safety analyses. The NRC staff also concludes that it is 10 not necessary to test the relief function at plants where it is not credited in the safety analyses 11 as part of the RCS overpressure protection. Therefore, it is acceptable to delete the existing SR 12 3.4.3.2 requirements.

13 14 A new SR 3.4.3.2 is proposed that states, Verify the as-found OPS lift pressures of the 15

[required] S/RVs are within the limits specified in the COLR. The frequency is proposed to be in 16 accordance with the IST Program. This SR provides verification of the upper as-found lift setting 17 requirements that were relocated from SR 3.4.3.1 to the COLR. The lower as-found settings are 18 established per the ASME OM Code. Elimination of the lower as-found setpoint from the STS is 19 acceptable because it does not affect any accident analyses, and does not contribute to the 20 protection of the RCS overpressure SL. Therefore, it is not required by 10 CFR 50.36 to be 21 included in TS.

22 23 As discussed, in Sections 3.0.5 Using the COLR for Controlling S/RV As-Found Limits, and 24 3.1 of this SE, the NRC staff has determined that the methodology that would be documented in 25 the COLR specification is acceptable for determining the allowable as-found upper tolerance(s) 26 for the S/RVs. The SR appropriately uses the allowable as-found upper tolerance(s), located in 27 the COLR, when verifying the ability of the S/RVs to perform their required functions.

28 29 The NRC staff concludes that the S/RVs credited for satisfying the proposed SR 3.4.3.2 must 30 have also met the proposed SR 3.4.3.1 when they were last installed. This is because SR 3.0.1 31 requires that the S/RVs be capable of meeting all applicable SRs at all times while operating in 32 the modes of applicability. So, 10 CFR 50.36(c)(3) will continue to be met because the SRs will 33 continue to ensure that the necessary quality of systems and components is being maintained.

34 35 3.3 NUREG-1434 Standard Technical Specification 3.4.4, Safety/Relief Valves (S/RVs) 36 37 3.3.1 Change to the Name of STS 3.4.4 38 39 The name of STS 3.4.4 is proposed to be changed from Safety/Relief Valves (S/RVs) to 40 Overpressure Protection System (OPS). This change is proposed to clarify that the S/RVs are 41 governed by several STS, not just STS 3.4.4. The proposed STS 3.4.4 only relates to the 42 cumulative behavior of the S/RVs acting in the safety mode, and relief mode to protect the RCS 43 from overpressure and is therefore proposed to be renamed to OPS. The name change does 44 not affect STS requirements, SRs, or other Required Actions, and will add clarity to the 45 3 There are two BWR/4 plants that require S/RVs operating in the relief mode to assure that the OPS can adequately control RCS pressure during postulated events. The traveler states that these two plants will retain SRs that verify that the relief mode valves credited for overpressure protection are functioning as needed.

proposed STS as it aligns with the OPS function. Therefore, the NRC staff concludes that the 1

proposed name change is acceptable.

2 3

3.3.2 Change to LCO 3.4.4 4

5 LCO 3.4.4 currently states, The safety function of [seven] S/RVs shall be OPERABLE, AND 6

The relief function of [seven] additional S/RVs shall be OPERABLE. The LCO is proposed to be 7

changed to, The OPS shall be OPERABLE. The controls contained in the COLR specification 8

will assure that the RCS pressure SL will not be exceeded because the OPS LCO is equivalent 9

to the existing requirement to have a specific number of S/RVs operable. The COLR 10 specification requires the overpressure, and other analyses that could be affected by individual 11 valve inoperability or changes to COLR values, to be evaluated by the licensee. The NRC staffs 12 evaluation of this change is provided in Section 3.0.5 of this SE The NRC staff finds that the 13 change is acceptable because the requirements within the revised STS 3.4.4 will ensure that 14 the S/RVs are capable of providing the overpressure protection required for the RCS.

15 16 3.3.3 Changes to Conditions and Required Actions in LCO 3.4.4 17 18 The existing Condition A of LCO 3.4.4 requires that if one required S/RV is inoperable that it be 19 restored to OPERABLE status in 14 days or per the RICT Program. Existing Condition B 20 requires if the Required Action of Condition A is not met, that the plant be in Mode 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

21 Existing Condition C requires that if two or more required S/RVs are inoperable that the plant be 22 in Mode 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and Mode 4 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. Conditions A, B, and C of this Action would be 23 deleted.

24 25 The note associated with Required Action B.1, which states that LCO 3.0.4.a is not applicable 26 when entering Mode 3, would be deleted as part of the elimination of the Action. The note is no 27 longer required because the new Condition A, described below, has a terminal action to be in 28 Mode 4, which is outside the applicability of the LCO.

29 30 A new Condition A is proposed that reads, OPS inoperable. In this condition, the Required 31 Actions are to be in Mode 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and Mode 4 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The traveler contains no 32 further Conditions or Actions.

33 34 While the overall reliability of the system is reduced when S/RVs are inoperable, individual 35 valves being inoperable may not impact the ability of the system to perform its function provided 36 the remaining valves required to assure OPS operability are functioning properly. If a licensee 37 determines that one or more S/RVs is inoperable it would have to determine if the individual 38 valve inoperability results in an OPS inoperability. In addition, the action requirements and 39 completion times for an inoperable OPS are the same as those currently in place for conditions 40 where S/RVs might be incapable of adequately limiting RCS pressure during postulated events.

41 The NRC staff finds that the requirements for the OPS to be operable provide adequate 42 assurance that the SL will be protected as evaluated in Section 3.0.7 of this SE, and therefore, 43 the proposed Condition and Required Actions are acceptable.

44 45 3.3.4 Changes to Surveillance Requirements 3.4.4.1 and 3.4.4.2 46 47 SR 3.4.4.1 is proposed to be revised to read, Verify the as-left OPS lift pressures of the 48

[required] safety/relief valves (S/RVs) are within +/-1% of the nominal setpoint. The proposed 49 frequency would be in accordance with the IST Program. The proposed SR also lists the 50 number of S/RVs in each setpoint group and the nominal setpoints for each group. The traveler 51 relocates the requirements for verification of the as-found setpoints from SR 3.4.4.1 to the 1

revised SR 3.4.4.3. The as-found upper limits are moved to the COLR, and the as-found lower 2

limits are established per the ASME OM Code. The traveler would delete an optional note that 3

allows up to two S/RVs to be moved to a lower group. The elimination of the note is acceptable 4

because only one plant in the BWR fleet includes this note in its TS so it should not be included 5

in the STS. The note also provided additional flexibility, so removing it is conservative. The 6

proposed change would also delete the alternate frequencies of [18] months and in accordance 7

with the SFCP. The proposed change simplifies the SR by using the requirements of the ASME 8

OM Code for the as-left setting frequencies and eliminating unnecessary language. The 9

requirement of the proposed SR 3.4.4.1 to set the S/RVs to within +/-1% of the nominal setpoint 10 helps to provide an expectation of operability for the valves throughout the operating cycle 11 considering the historical drift associated with as-found testing. The as-found limits are 12 discussed below under SR 3.4.4.3. The SR is reworded in terms of the OPS. The elimination of 13 the alternative frequencies is acceptable because the IST Program frequency requirements are 14 adequate to assure that the valves have as-left settings that maintain adequate safety. The IST 15 Program establishes test frequencies to assess operational readiness and identify degradation 16 since the previous test conducted under the ASME OM Code. The updated SR 3.4.4.1, the 17 reworded SR 3.4.4.2, and the revised SR 3.4.4.3 provide adequate requirements to protect the 18 RCS overpressure SL. Therefore, the NRC staff concludes that the proposed change is 19 acceptable. The acceptability of the three SRs to provide adequate protection of the SL are 20 discussed throughout this Section (3.3.4).

21 22 The existing SR 3.4.4.2 would be reworded to state, Verify each S/RV required to act in the 23 relief mode actuates on an actual or simulated automatic initiation signal. The rewording is 24 intended to clarify that the relief mode is a feature required for overpressure protection. All 25 BWR/6 plants credit some valves acting in the relief mode for RCS overpressure protection. The 26 NRC staff concludes that the change is acceptable since the requirement for the SR does not 27 change and it remains clear which S/RVs are required to be tested to assure that the relief 28 mode is functioning acceptably to provide overpressure protection.

29 30 The existing SR 3.4.4.3 that requires verification that each S/RV opens when manually actuated 31 would be deleted. As discussed in Section 3.2.4 of this SE, the NRC staff finds this deletion to 32 be acceptable for BWR/6 plants for the same reasons it was found acceptable for BWR/4 33 plants.

34 35 The traveler would replace the existing SR 3.4.4.3 with an SR that states, Verify the as-found 36 OPS lift pressures of the [required] S/RVs are within the limits specified in the COLR. The 37 frequency is proposed to be in accordance with the IST Program. This SR provides the upper 38 as-found lift setting requirements that were deleted from SR 3.4.4.1. The lower as-found 39 settings are established per the ASME OM Code. Elimination of the lower as-found setpoint 40 from the STS is acceptable because it does not affect any accident analyses, and does not 41 contribute to the protection of the RCS overpressure SL. Therefore, it is not required by 42 regulations to be in TS. See the discussion in Section 3.0.4 above titled Removal of the Lower 43 As-found Tolerance. The NRC staff has found that the frequencies for testing specified in the 44 OM Code provide adequate assurance that the S/RV testing assure operational readiness.

45 46 As discussed above in Section 3.2.4 for BWR/4 plants, and as discussed in Sections 3.0.5, 47 Using the COLR for Controlling S/RV As-Found Limits, and 3.1 of this SE, the NRC staff has 48 determined that the methodology that would be documented in the COLR specification is 49 acceptable for determining the as-found tolerances for the S/RVs and provides assurance that 50 the RCS pressure SL will not be exceeded because the COLR specification requires that an 51 NRC-approved method be used to determine the allowable as-found upper tolerance(s). This 1

provides reasonable assurance that the allowable as-found upper tolerance(s) will be protective 2

of the SL. Therefore, the NRC staff finds that the proposed SR is acceptable.

3 4

The NRC staff concludes that the S/RVs credited for satisfying the proposed SR 3.4.4.3 must 5

have also met the proposed SR 3.4.4.1 when they were last installed. In other words, the 6

licensee cannot use one subset of valves for SR 3.4.4.3 requirements and a different subset of 7

valves to meet the SR 3.4.4.1 requirements. This is necessary to satisfy 10 CFR 50.36(c)(3) 8 and SR 3.0.1 which assure that the necessary quality of systems and components is maintained 9

by requiring that the S/RVs meet the SRs at all times during the modes of applicability.

10 11 3.4 Evaluation of Proposed STS Bases Changes 12 13 This traveler will become part of the next major revision of the NRCs STS Bases NUREG 14 documents. As such, the staff assessed the Bases included in TSTF-576 to determine if the 15 Bases addressed the items in the Commissions Final Policy Statement described in Section 2.3 16 above. For the reasons below, the NRC staff found that the Bases sufficiently met the Final 17 Policy Statement.

18 19 The Final Policy Statement says that Bases should provide the justification for the TS, i.e.,

20 discuss which Policy Statement criterion requires it to be in the TS. This standard is met 21 because the STS Bases markup states that the OPS satisfies Criterion 3 of 10 CFR 22 50.36(c)(2)(ii) because the OPS protects the RCS, a fission product barrier. Criterion 3 requires, 23 structure, system, or component that is part of the primary success path and which functions 24 or actuates to mitigate a DBA or transient that either assumes the failure of or presents a 25 challenge to the integrity of a fission product barrier, have an LCO included in the STS. Since 26 the OPS protects the RCS pressure boundary the NRC staff concludes that use of Criterion 3 is 27 correct.

28 29 The Final Policy Statement says that Bases should explain why an LCO was determined to be 30 the lowest functional capability or performance level for the system or component in question 31 necessary for safe operation of the facility and, what are the reasons for the Applicability of the 32 LCO. These standards are met because the STS Bases markup states that the OPS operability 33 will ensure that the SL 2.1.2 is protected. An inoperable OPS could result in the SL 2.1.2 being 34 exceeded. The Bases markup states that the LCO is applicable in Modes 1, 2, and 3 since there 35 may be considerable energy in the reactor in these Modes of applicability and the limiting design 36 basis transients are assumed to occur in these modes. In lower modes the SL would not be 37 challenged. The NRC staff concludes that the LCO and Applicability in the STS Bases are 38 acceptable because the description explains why the LCO is the lowest functional capability and 39 the reason for the Applicability of the LCO.

40 41 The Final Policy Statement says that the Bases for each Action should explain why the remedial 42 action should be taken if the associated LCO cannot be met, how the Action relates to other 43 Actions associated with the LCO, and what justifies continued operation of the system or 44 component at the reduced state from the state specified in the LCO for the allowed time period.

45 These standards are met for the following reasons. The Action for an inoperable OPS requires 46 that the plant be taken out of the applicability of the LCO if it is not met. The Action requires the 47 plant to be in Mode 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and Mode 4 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The STS Bases state that this is 48 acceptable because it allows adequate time to exit the applicability without challenging plant 49 systems. The Action takes the plant out of the Applicability as rapidly as is possible without 50 excess risk of causing a transient during the evolution. The NRC staff concludes that the Action 51 STS Bases are acceptable because the description supports understanding of the LCO and 1

provides a justification for the completion time.

2 3

The Final Policy Statement says that the Bases for each SR should address the specific 4

functional requirement that the surveillance is designed to verify, explain why the surveillance is 5

necessary at the specified frequency to assure that the system or component function is 6

maintained, that facility operation will be within the safety limits, and that the LCO will be met.

7 These standards are met for the following reasons. The proposed STS Bases explain that the 8

SR for as-left testing is required to meet the IST Program, including the required frequency. The 9

as-left SR also specifies that the S/RVs be set within one percent of the nominal setpoint. The 10 SR for the as-found testing is stated to ensure that the assumptions of the overpressure 11 analysis are met. This testing is also described as being performed per the IST Program and 12 states that the OPS S/RV lift pressures are specified in the COLR.

13 14

4.0 CONCLUSION

15 16 The NRC staff concludes that the proposed changes to STS 3.4.3 (NUREG-1433) and STS 17 3.4.4 (NUREG-1434) are acceptable because, as discussed above, the revisions described in 18 TSTF-576 will provide appropriate limiting conditions for operation, actions to be taken if the 19 limiting conditions for operation are not met, appropriate SRs that assure that the OPS is 20 maintained such that the limiting condition for operation will be met, and provide the necessary 21 administrative controls (i.e., provisions related to procedures) to assure operation of the facility 22 in a safe manner. The settings for S/RVs acting in the safety mode at all plants and the S/RVs 23 acting in the relief mode at the plants that use relief mode for the OPS will continue to provide 24 adequate overpressure protection that assures plant operation will be within the relevant safety 25 analyses. Therefore, the NRC staff finds that the proposed changes to the existing S/RV STS 26 are acceptable because the proposed changes meet the requirements of 10 CFR 50.36(c)(2)(i) 27 (limiting conditions for operation and action statements) and 10 CFR 50.36(c)(3) (SRs), and 10 28 CFR 50.36(c)(5) (administrative controls). Last, the staff finds that the Bases proposed to be 29 incorporated into the STS Bases NUREG-1433 Vol. 2 and NUREG-1434 Vol. 2 address the 30 questions that the Commission stated should be addressed in its Final Policy Statement on 31 Technical Specifications Improvements for Nuclear Power Reactors and provide references to 32 appropriate licensing documentation (e.g., FSAR, Topical Report) to support the Bases.

33 34 Principal Contributors:

S. Smith, NRR/DSS/STSB 35 R. Beaton, NRR/DSS/SNSB 36 N. Hansing, NRR/DEX/EMIB 37 B. Parks, NRR/DSS/SFNB 38 R. Elliott, NRR/DSS/STSB 39 40 Date: August 1, 2024 41