Text

Draft SE of TSTF-585, Revision 5, Revise LCO 3.0.3 to Require Managing Risk
	ML25335A206
Person / Time
Site:	Technical Specifications Task Force
Issue date:	12/23/2025
From:	Robert Elliott, John Hughey; Office of Nuclear Reactor Regulation
To:	; Technical Specifications Task Force
References
	EPID L-2023-PMP-0000
	Download: ML25335A206 (19)
	v • d • e

DRAFT SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION 1

2 TECHNICAL SPECIFICATIONS TASK FORCE TRAVELER 3

4 TSTF-585, REVISION 5, "REVISE LCO 3.0.3 TO REQUIRE MANAGING RISK" 5

6 USING THE CONSOLIDATED LINE ITEM IMPROVEMENT PROCESS 7

8 (EPID: L-2023-PMP-0000) 9 10

1.0 INTRODUCTION

11 12 By letter dated September 17, 2025 (Agencywide Documents Access and Management System 13 (ADAMS) Accession No. ML25260A487) the Technical Specifications Task Force (TSTF) 14 submitted traveler TSTF-585, Revision 5, Revise LCO [Limiting Condition for Operation] 3.0.3 to 15 Require Managing Risk, ( TSTF-585). TSTF-585 proposed changes to the Standard Technical 16 Specifications (STS) for boiling-water reactor (BWR) designs and pressurized-water reactor 17 (PWR) designs under the consolidated line item improvement process (CLIIP). Upon approval, 18 this traveler will be made available for adoption, and the changes will be incorporated into future 19 revisions of the following NRC STS1:

20 21 NUREG-1430, Standard Technical Specifications, Babcock and Wilcox Plants, Volume 1, 22 Specifications, and Volume 2, Bases, Revision 5, September 2021 (ML21272A363 and 23 ML21272A370, respectively).

24 NUREG-1431, Standard Technical Specifications, Westinghouse Plants, Volume 1, 25 Specifications, and Volume 2, Bases, Revision 5, September 2021 (ML21259A155 and 26 ML21259A159, respectively).

27 NUREG-1432, Standard Technical Specifications, Combustion Engineering Plants, 28 Volume 1, Specifications, and Volume 2, Bases, Revision 5, September 2021 29 (ML21258A421 and ML21258A424, respectively).

30 NUREG-1433, Standard Technical Specifications, General Electric BWR/4 Plants 31 Volume 1, Specifications, and Volume 2, Bases, Revision 5, September 2021 32 (ML21272A357 and ML21272A358, respectively).

33 NUREG-1434, Standard Technical Specifications, General Electric BWR/6 Plants 34 Volume 1, Specifications, and Volume 2, Bases, Revision 5, September 2021 35 (ML21271A582 and ML21271A596, respectively).

36 37 The proposed changes would revise the shutdown requirements in STS LCO 3.0.3 by requiring 38 the assessment and management of plant risk whenever LCO 3.0.3 is entered. The traveler 39 proposed that the risk assessment and implementation of any appropriate risk management 40 actions must be completed within six hours. If the assessment determined that the risk of 41 continuing plant operation is acceptable, the traveler proposed a 24-hour Completion Time (CT) 42 from entry into LCO 3.0.3 to initiate action for a shutdown. The 24-hour CT would allow time to 43 perform repairs, request relief from the NRC, and/or to prepare for a plant shutdown. The 44 1NUREG-1433 provides the STS for BWR/4 plant designs, but is also representative of the BWR/2, BWR/3, and, in this case, of the BWR/5 plant design.

NUREG-1434 provides the STS for BWR/6 plant designs but is also representative in some cases of the BWR/5 plant design.

proposed change also revises or adds some technical specifications (TS) Required Actions to 1

require a plant shutdown instead of entry into LCO 3.0.3, because the STS direct entry into 2

LCO 3.0.3 or may result in implicit entry into LCO 3.0.3.

3 4

1.1 Description of the Current LCO 3.0.3 5

6 The current STS LCO 3.0.3 in NUREG-1430, 1431, and 1432 for PWRs requires action to be 7

initiated within one hour to place the unit, as applicable, in Mode 3 within 7 hours8.101852e-5 days 0.00194 hours 1.157407e-5 weeks 2.6635e-6 months , Mode 4 within 8

13 hours1.50463e-4 days 0.00361 hours 2.149471e-5 weeks 4.9465e-6 months , and Mode 5 within 37 hours4.282407e-4 days 0.0103 hours 6.117725e-5 weeks 1.40785e-5 months when:

9 10

1) an LCO is not met and the associated actions are not met, 11

2) an associated action is not provided, or 12

3) if directed to enter LCO 3.0.3 by the associated actions.

13 14 LCO 3.0.3 in NUREG-1433 and 1434 for boiling water reactors (BWRs) differs in that it requires 15 the unit to be in Mode 2 within 7 hour8.101852e-5 days 0.00194 hours 1.157407e-5 weeks 2.6635e-6 months s2, Mode 3 within 13 hours1.50463e-4 days 0.00361 hours 2.149471e-5 weeks 4.9465e-6 months , and Mode 4 within 37 hours4.282407e-4 days 0.0103 hours 6.117725e-5 weeks 1.40785e-5 months .

16 However, the reasons for entry into LCO 3.0.3 are the same for both BWRs and PWRs.

17 18 The STS Bases for LCO 3.0.3 states that upon entering LCO 3.0.3, one hour is allowed to 19 prepare for an orderly shutdown before initiating a change in unit operation. This one-hour 20 timeframe includes time to permit the operator to coordinate the reduction in electrical 21 generation with the load dispatcher to ensure the stability and availability of the electrical grid.

22 The time limits in LCO 3.0.3 also permit the shutdown to proceed in a controlled and orderly 23 manner that is well within the specified maximum cooldown rate and is also well within the 24 capabilities of the unit, assuming that only the minimum required equipment is operable.

25 26 LCO 3.0.3 is applicable in Modes 1, 2, 3, and 4 for PWRs and Modes 1, 2, and 3 for BWRs.

27 28 1.2 Proposed Changes to the STS 29 30 TSTF-585 proposes to restructure LCO 3.0.3 by replacing the one-hour shutdown preparation 31 time with a requirement to assess the risk and implement appropriate risk management actions 32 (RMAs) within six hours. In addition, if risk is assessed and managed, and is subsequently 33 determined to be acceptable, operation may continue for a total of 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months after unplanned 34 entry into LCO 3.0.3 (i.e., an additional 18 hours2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months beyond the initial six hours for the risk 35 assessment and implementation of RMAs). If the plant is still in LCO 3.0.3 at the end of the 36 24-hour period, the initiation of a shutdown is required. In addition, a shutdown is required to be 37 initiated at the end of the six-hour period [i]f the risk assessment determines that continuing 38 operation is not acceptable, the risk assessment was not completed, the appropriate risk 39 management actions were not implemented, or entry into LCO 3.0.3 was planned. The 40 changes proposed in TSTF-585 are shown in Table 1 and are compared to the existing 41 LCO 3.0.3. Text deletions are shown in strikeout font, and additions are shown in bold italicized 42 font.

43 2 TSTF-597, Revision 0, "Eliminate LCO 3.0.3 Mode 2 Requirement," was approved by the NRC on December 26, 2024 (ML24358A224.) TSTF-597 removed the BWR STS requirement to be in Mode 2 within 7 hours8.101852e-5 days 0.00194 hours 1.157407e-5 weeks 2.6635e-6 months . Adoption of TSTF-597 and TSTF-585 in any order does not affect the acceptability of either traveler.

Table 1 1

Comparison of Existing LCO 3.0.3 to the TSTF-585 Proposed LCO 3.0.3 2

Current LCO 3.0.3 (PWR/BWR)

Proposed LCO 3.0.3 (PWR/BWR)

When an LCO is not met and the associated ACTIONS are not met, an associated ACTION is not provided, or if directed by the associated ACTIONS, the unit shall be placed in a MODE or other specified condition in which the LCO is not applicable. Action shall be initiated within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months to place the unit, as applicable, in:

a. MODE [3/2] within 7 hours8.101852e-5 days 0.00194 hours 1.157407e-5 weeks 2.6635e-6 months ,

b. MODE [4/3] within 13 hours1.50463e-4 days 0.00361 hours 2.149471e-5 weeks 4.9465e-6 months , and

c. MODE [5/4] within 37 hours4.282407e-4 days 0.0103 hours 6.117725e-5 weeks 1.40785e-5 months .

Where corrective measures are completed that permit operation in accordance with the LCO or ACTIONS, completion of the actions required by LCO 3.0.3 is not required.

When an LCO is not met and the associated ACTIONS are not met, an associated ACTION is not provided, or if directed by the associated ACTIONS, the unit shall be placed in a MODE or other specified condition in which the LCO is not applicable.

Within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months perform a risk assessment addressing inoperable systems and components and implement appropriate risk management actions. If the risk assessment determines that continuing operation is acceptable, the appropriate risk management actions are implemented, and entry into LCO 3.0.3 was unplanned, then action Action shall be initiated within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months 1 hour to place the unit, as applicable, in:

a. MODE [3/2] within 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months ,

b. MODE [4/3] within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months , and

c. MODE [5/4] within 60 hours6.944444e-4 days 0.0167 hours 9.920635e-5 weeks 2.283e-5 months .

If the risk assessment determines that continuing operation is not acceptable, the risk assessment was not completed, the appropriate risk management actions were not implemented, or entry into LCO 3.0.3 was planned, then action shall be initiated to place the unit, as applicable, in:

a. MODE [3/2] within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months ,

b. MODE [4/3] within 18 hours2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months , and

c. MODE [5/4] within 42 hours4.861111e-4 days 0.0117 hours 6.944444e-5 weeks 1.5981e-5 months .

All times are determined from entry into LCO 3.0.3.

Exceptions to this Specification are stated in the individual Specifications.

If Where corrective measures are completed that permit operation in accordance with the LCO or ACTIONS, then completion of the actions required by LCO 3.0.3 is not required.

1 To determine if the delay in shutting down for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months is acceptable, TSTF-585 proposes that a 2

risk assessment and RMAs be performed utilizing the methodology used for the Maintenance 3

Rule. Specifically, as stated in the TSTF-585 proposed Bases, [t]he risk assessments will be 4

conducted using the procedures and guidance endorsed by Regulatory Guide [(RG)] 1.160, 5

"Monitoring the Effectiveness of Maintenance at Nuclear Power Plants." RG 1.160 endorses the 6

guidance in Section 11 of Nuclear Utility Management and Resources Council (NUMARC) 93-7 01, Industry Guideline for Monitoring the Effectiveness of Maintenance at Nuclear Power 8

Plants. All relevant elements of the risk assessment description in Section 11 will be included.

9 Acceptability for the additional 24-hour time is based, in part, on the guidelines in 10 NUMARC 93-01, which state there should be a minimal increase in risk after implementation of 11 RMAs. In addition to the proposed limits on the increase in incremental risk, the NUMARC 93-12 01 risk assessment methodology also provides for consideration of a limit on the configuration-13 specific instantaneous risk. The proposed change stipulates that the incremental and 14 configuration-specific instantaneous risk value limits described in NUMARC 93-01, 15 Section 11.3.7.2, are required to be implemented when performing the quantitative risk 16 assessment for the proposed revision to TS 3.0.3. Therefore, the proposed change would use 17 the NRC-endorsed NUMARC 93-01 risk assessment and management methodology, elevating 18 some considerations and limits of the NUMARC guidance to requirements. Compliance with 19 these requirements would allow the licensee to extend the time to initiate a shutdown up to 20 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

21 22 Implicit entries into LCO 3.0.3 can occur when an LCO is not met, and there is no associated 23 Action provided for that condition. There are also several places in the STS where entries into 24 LCO 3.0.3 are explicitly required by the STS Actions. TSTF-585 identifies several LCOs where 25 implicit or explicit entries into the revised LCO 3.0.3 may not be appropriate (i.e., the plant would 26 be in a condition where an immediate shutdown would be appropriate). Accordingly, TSTF-585 27 proposes the following changes to the following LCOs to remove these implicit or explicit entries 28 into LCO 3.0.3:

29 30 NUREG-1430, TS 3.1.6, Axial Power Shaping Rod (APSR) Alignment Limits, would be 31 modified to require a plant shutdown if more than one APSR is misaligned.

32 NUREG-1431, TS 3.6.10, Hydrogen Ignition System (HIS), would be modified to require a 33 plant shutdown if more than one train of the HIS were inoperable or if there were more than 34 one containment region with no operable hydrogen ignitor.

35 NUREG-1430, NUREG-1431, and NUREG-1432, TS 3.7.2, "Main Steam Isolation Valves 36 (MSIVs)" would be modified to require placing the unit in Mode 2 when more than one MSIV 37 is inoperable while in Mode 1.

38 NUREG-1430, NUREG-1431, NUREG-1432 NUREG-1433, and NUREG-1434, TS 3.8.4, 39 "DC Sources - Operating" would be modified to require shutdown if more than one DC 40 electrical power subsystem were inoperable.

41 NUREG-1430, NUREG-1431, NUREG-1432 NUREG-1433, and NUREG-1434, TS 3.8.9, 42 "Distribution Systems - Operating" would be modified to require a shutdown when two or 43 more electrical power distribution subsystems are inoperable resulting in a loss of safety 44 function.

45 46 TSTF-585 also notes some editorial changes. Each of the specified Mode change CTs specified 47 in the current LCO 3.0.3 are adjusted in the proposed LCO 3.0.3 to reflect the replacement of the 48 existing one-hour shutdown preparation time with the proposed increased time for initiating a 49 shutdown of either six or 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , as appropriate. The change in CTs does not change the 50 amount of time allowed for the process of shutting down the plant. It reflects a change in when 1

the shutdown is required to begin based on the time of entry into LCO 3.0.3. Accordingly, these 2

changes are editorial.

3 4

One other editorial change is proposed. TSTF-585 proposes to change the sentence that states, 5

"Where corrective measures are completed that permit operation in accordance with the LCO or 6

ACTIONS, completion of the actions required by LCO 3.0.3 is not required" to read "If corrective 7

measures are completed that permit operation in accordance with the LCO or ACTIONS, 8

completion of the actions required by LCO 3.0.3 is not required." This is an editorial change for 9

clarity and does not change the requirements of LCO 3.0.3.

10 11 1.3 Proposed Changes to the STS Bases 12 13 TSTF-585 proposes to update the STS Bases to provide a description of the revised LCO 3.0.3 14 structure described above. In addition, the proposed LCO 3.0.3 Bases discussion would amplify 15 how the requirement to assess and manage risk would be implemented at an operating plant 16 (i.e., when a plant receives a license amendment approving the adoption of TSTF-585).

17 Specifically:

18 Regarding the assessment and management of risk, the proposed LCO 3.0.3 Bases would 19 state:

20 o The risk assessments will be conducted using the procedures and guidance endorsed by 21 Regulatory Guide 1.160, Monitoring the Effectiveness of Maintenance at Nuclear Power 22 Plants. Regulatory Guide 1.160 endorses the guidance in Section 11 of NUMARC 93-01, 23 Industry Guideline for Monitoring the Effectiveness of Maintenance at Nuclear Power 24 Plants. All relevant elements of the risk assessment description in Section 11 will be 25 included.

26 o Upon entering LCO 3.0.3, a risk assessment addressing inoperable systems and 27 components must be completed and appropriate risk management actions must be 28 implemented within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months .

29 o The risk assessment must consider all inoperable equipment regardless of whether the 30 equipment is included in the normal 10 CFR 50.65(a)(4) risk assessment scope.

31 o A formal cause or apparent cause evaluation is not required because of the limited time 32 available, but the likely cause of the conditions that resulted in LCO 3.0.3 entry are 33 considered. If the extent of condition is unknown, the risk assessment should consider 34 the possibility of common cause failure either numerically or through risk management 35 actions.

36 o Whenever practicable a quantitative value for risk shall be determined. If determination 37 of a quantitative value for risk is not practicable, a qualitative assessment of risk may be 38 used with appropriate consideration of the plant conditions and uncertainties to determine 39 whether continued operation for a limited time is acceptable.

40 o The determination that continuing operation is acceptable will be documented in 41 sufficient detail to allow a knowledgeable individual to understand the basis for the 42 determination.

43 Regarding the acceptance criteria for continued operation, the proposed LCO 3.0.3 Bases 44 would state that continued operation for a limited time is acceptable if the risk assessment 45 determines that for the current plant configuration:

46 o [T]he Incremental Core Damage Probability (ICDP) is less than 1E-5, and the 1

Incremental Large Early Release Probability (ILERP) is less than 1E-6.

2 o Non-quantifiable factors will also be assessed.

3 o The configuration-specific Core Damage Frequency (CDF) and Large Early Release 4

Frequency (LERF) will be evaluated to identify high-risk situations. A 5

configuration-specific CDF in excess of 1E-3/year or LERF in excess of 1E-4/year does 6

not support continuing operation.

7 o The impact on plant risk is evaluated from the baseline, zero-maintenance, condition.

8 o If during the 24-hour period the plant configuration changes such that plant risk may be 9

increased, the risk must be reassessed. If the configuration no longer supports continuing 10 plant operation, action must be initiated to shut down the unit in accordance with the 11 LCO 3.0.3 requirements.

12 13 TSTF-585 proposed the following editorial changes to the LCO 3.0.3 Bases to improve 14 consistency and clarity:

15 16 LCO 3.0.3 describes three conditions for entry. Accordingly, the LCO 3.0.3 Bases are 17 revised to be consistent with the TS.

18 19 The LCO 3.0.3 Bases state, This Specification delineates the time limits for placing the 20 unit in a safe MODE or other specified condition when operation cannot be maintained 21 within the limits for safe operation as defined by the LCO and its ACTIONS. TSTF-585 22 proposes to delete the phrase, for safe operation, for clarity.

23 24

2.0 REGULATORY EVALUATION

25 26 As stated in Title 10 of the Code of Federal Regulations (10 CFR) Section 50.36(a)(1), an 27 application for a license authorizing operation of a production or utilization facility shall include 28 proposed TS in accordance with the requirements in 10 CFR 50.36. The regulation further 29 provides that a summary statement of the bases or reasons for such specifications, other than 30 those covering administrative controls, shall also be included in the application, but shall not 31 become part of the TS.

32 33 Specifically, 10 CFR 50.36(b) requires that:

34 35 Each license authorizing operation of a utilization facility will include 36 technical specifications. The technical specifications will be derived from the 37 analyses and evaluation included in the safety analysis report, and amendments 38 thereto, submitted pursuant to [10 CFR] 50.34 [Contents of applications; 39 technical information]. The Commission may include such additional technical 40 specifications as the Commission finds appropriate.

41 42 10 CFR 50.36(c) further states the categories of items that must be included in TS. Among other 43 items, the regulation requires that TS include LCOs. 10 CFR 50.36(c)(2)(i) provides that:

44 45 Limiting conditions for operation are the lowest functional capability or 46 performance levels of equipment required for safe operation of the facility. When a 47 limiting condition for operation of a nuclear reactor is not met, the licensee shall 48 shut down the reactor or follow any remedial action permitted by the technical 1

specifications until the condition can be met.

2 3

LCO 3.0.3 implements 10 CFR 50.36(c)(2)(i) in that it requires a plant to shut down when an 4

LCO is not met and: 1) there are no remedial actions provided in the TS, or 2) the remedial 5

actions provided in the TS are not completed in the time allowed by the TS.

6 7

As described in the Commissions Final Policy Statement on Technical Specifications 8

Improvements for Nuclear Power Reactors (58 FR 39132, dated July 22, 1993), [t]he new STS 9

should include greater emphasis on human factors principles in order to add clarity and 10 understanding to the text of the STS, and should also provide improvements to the Bases 11 Section of Technical Specifications which provides the purpose for each requirement in the 12 specification. The improved vendor-specific STS were developed and issued by the NRC in 13 September 1992.

14 15 The Summary Section of the Commissions Final Policy Statement on Technical Specifications 16 Improvements for Nuclear Power Reactors, states, in part:

17 18 Implementation of the Policy Statement through implementation of the improved 19 STS is expected to produce an improvement in the safety of nuclear power 20 plants through the use of more operator-oriented Technical Specifications, 21 improved Technical Specification Bases, reduced action statement induced plant 22 transients, and more efficient use of NRC and industry resources.

23 24 Section IV, The Commission Policy, of the Final Policy Statement on Technical Specifications 25 Improvements for Nuclear Power Reactors, further states, in part:

26 27 The purpose of Technical Specifications is to impose those conditions or 28 limitations upon reactor operation necessary to obviate the possibility of an 29 abnormal situation or event giving rise to an immediate threat to the public health 30 and safety by identifying those features that are of controlling importance to 31 safety and establishing on them certain conditions of operation which cannot be 32 changed without prior Commission approval.

33 34

[T]he Commission will also entertain requests to adopt portions of the 35 improved STS [(e.g., TSTF-585)], even if the licensee does not adopt all STS 36 improvements. The Commission encourages all licensees who submit 37 Technical Specification related submittals based on this Policy Statement to 38 emphasize human factors principles.

39 40 In accordance with this Policy Statement, improved STS have been developed 41 and will be maintained for each NSSS [nuclear steam supply system] owners 42 group. The Commission encourages licensees to use the improved STS as the 43 basis for plant-specific Technical Specifications. [I]t is the Commission intent 44 that the wording and Bases of the improved STS be used in the Technical 45 Specification related submittal to the extent practicable.

46 47 Paragraph (a)(4) of 10 CFR 50.65, Requirements for monitoring the effectiveness of 48 maintenance at nuclear power plants, (the Maintenance Rule) requires, in part, that:

49 50

[b]efore performing maintenance activities (including but not limited to 51 surveillance, post-maintenance testing, and corrective and preventive 1

maintenance), the licensee shall assess and manage the increase in risk that 2

may result from the proposed maintenance activities. The scope of the 3

assessment may be limited to structures, systems, and components that a 4

risk-informed evaluation process has shown to be significant to public health and 5

safety.

6 7

NUMARC 93-01, Industry Guideline for Monitoring the Effectiveness of Maintenance at Nuclear 8

Power Plants, Section 11.0, Assessment of Risk Resulting from Maintenance Activities, 9

provides a methodology that is an acceptable approach to manage and assess risk associated 10 with maintenance activities. This methodology has been endorsed by the NRC in RG 1.160, 11 Revision 4, Monitoring the Effectiveness of Maintenance at Nuclear Power Plants. TSTF-585 12 proposes to revise LCO 3.0.3 to require the assessment and management of risk using this 13 NRC-endorsed methodology.

14 15 The NRC staffs guidance for the review of TS is provided in NUREG-0800, Standard Review 16 Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR [Light-Water 17 Reactor] Edition (SRP), Chapter 16.0, Technical Specifications, Revision 3, dated March 18 2010 (ML100351425). As described therein, as part of the regulatory standardization effort, the 19 NRC staff has prepared STS for each of the LWR nuclear designs listed in Section 1.0 of this 20 safety evaluation (SE).

21 22

3.0 TECHNICAL EVALUATION

23 24 The NRC staff reviewed traveler TSTF-585, which proposed changes to NUREGs-1430, -1431, 25

-1432, -1433, and -1434. The regulatory framework the NRC staff used to determine the 26 acceptability of the proposed changes consists of the requirements and guidance listed in 27 Section 2.0 of this SE.

28 29 3.1 Operating Experience Review 30 31 The NRC staff reviewed the operating experience for the last 15 years involving licensee entries 32 into LCO 3.0.3. The results of the staffs review are shown in Table 2 below. The data shows that 33 only three out of 54 events where a licensee entered LCO 3.0.3 resulted in a complete shutdown 34 of the plant. In all other cases (i.e., 94.4% of the cases), licensees were able to restore the 35 required structures, systems and components (SSCs) to operable status and exit LCO 3.0.3 36 before completing the shutdown. Based on the data, the staff concludes that implementing 37 alternatives to allow licensees some time to assess risk and restore equipment operability before 38 requiring the plant to be shut down is appropriate as this would avoid unnecessary perturbation 39 of the plant (i.e., starting an unnecessary transition of the plant to shut down) while repairs are 40 being completed.

41 42 1

Table 2 2

Operating Experience Related to LCO 3.0.3 Entries Between 2010 and 2025 3

4 LCO 3.0.3 Events Number Percentage Total LCO 3.0.3 Events Reported 54 100%

Number of LCO 3.0.3 entries exited within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months 26 48.1%

Number of LCO 3.0.3 entries exited between 1 and 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months 22 40.7%

Number of LCO 3.0.3 entries exited after 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months but prior to completing shutdown 3

5.6%

Number of LCO 3.0.3 entries that resulted in a completed shutdown 3

5.6%

5 The NRC staff also evaluated the causes of LCO 3.0.3 entries over the last 15 years. Table 3 6

below illustrates the results of this review. The data shows that the primary reason for LCO 3.0.3 7

entries is a loss of a TS function. However, many of the reported loss of function events were a 8

direct result of failing to meet an aspect of the accident analysis (e.g., high energy line break 9

barrier removed or seismic protection missing), failure to meet a conservative surveillance 10 acceptance criterion (e.g., excess gas in a piping system), or due to small leaks where the 11 affected systems were conservatively declared inoperable. In these cases, the affected SSCs 12 were still available to perform their safety function even though they were inoperable per the TS.

13 The staffs review determined that only 20 of the 53 reported loss of function LCO 3.0.3 entries 14 resulted from a TS SSC being sufficiently degraded such that the SSC was completely incapable 15 of performing its specified safety function (referred to in Table 3 below as an Actual Loss of 16 Function). In addition, out of the 20 events shown as Actual Loss of Function, 7 events were 17 caused by the failure of a ventilation or air conditioning system that provided cooling to the 18 control room or to rooms housing safety related equipment used for accident mitigation. These 19 failures typically do not cause an immediate loss of the supported safety systems accident 20 mitigation capability and could, in many cases, be mitigated by RMAs while repair work is 21 ongoing. This means that a complete loss of safety function only occurred in 13 of the 54 22 LCO 3.0.3 entries. Accordingly, from this analysis, the staff determined that in approximately 23 75% of the LCO 3.0.3 entries, licensees retained the availability of the accident mitigation safety 24 function although it was degraded sufficiently to require entry into LCO 3.0.3. This suggests that 25 a risk management strategy would be a reasonable approach for LCO 3.0.3 entries.

26 27 28 29 Table 3 1

Reported Causes of LCO 3.0.3 Entries 2

3 Cause of LCO 3.0.3 Entry Number of LCO 3.0.3 Entries Percentage of Entries Control Room Ventilation or Air Conditioning 11 20.3%

Voids in Piping Systems 6

11.1%

Natural Phenomena or High Energy Line Break Protection 5

9.3%

Small Leaks and Leakage Detection 6

11.1%

LCO Not Met with No TS Action Provided 1

1.9%

Actual Loss of Function 20 37%

Miscellaneous Other Causes 5

9.3%

Total Reported Loss of Function 53 98.1%

LCO Not Met with No TS Action Provided 1

1.9%

Total Number Of LCO 3.0.3 Entries 54 100%

4 The data also shows a significant reduction in the number of LCO 3.0.3 entries since 2019. In 5

October 2019, the Nuclear Energy Institute (NEI) issued NEI 18-03, Operability Determination 6

(ML19284C872), and the NRC issued an update to Inspection Manual Chapter (IMC) 0326, 7

Operability Determinations (ML19273A878). These documents provided updated guidance and 8

clarification on determining operability of TS SSCs. From 2010 through 2018, there were 9

47 entries into LCO 3.0.3, an average of approximately five entries per year. Sixteen of those 10 entries (34%) were subsequently retracted after further evaluation by the licensee. Since 2019, 11 only seven LCO 3.0.3 entries have occurred, an average of approximately one entry per year, 12 and none have been retracted. Based on the guidance updates from 2019 and the operating 13 experience data, the NRC staff concludes that LCO 3.0.3 entries will likely continue to be a rare 14 occurrence.

15 16 Based on the overall operating experience evaluation, the NRC staff concludes that the 17 operating experience demonstrates that LCO 3.0.3 should be revised to allow actions that are 18 commensurate with the risk significance of the event causing entry into LCO 3.0.3. This 19 conclusion is based on the operating experience data which demonstrates that: 1) LCO 3.0.3 20 entries rarely result in a complete shutdown of the plant, and 2) LCO 3.0.3 entries often result 21 from low-risk significance events. In addition, starting a reduction in power (i.e., shutdown) while 22 conducting repairs and then returning to full power could increase the possibility of a transient.

23 As a result, the existing requirement to immediately shut down the plant likely increases the plant 24 risk compared to taking appropriate RMAs and completing repairs of the inoperable equipment 25 while remaining at power.

26 27 3.2 Methodology for Assessment and Management of Risk 1

2 TSTF-585 proposes a modification to LCO 3.0.3 to revise the one-hour CT to begin a shutdown 3

to a six-hour CT to begin a shutdown. In addition, the six-hour CT would require different actions 4

than currently specified. Specifically, during the six hours, the licensee would be required to 5

assess plant risk based on the current condition of the plant, implement RMAs, and determine if 6

continued operation up to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months is acceptable based on the assessed risk. If the risk is 7

determined to be acceptable and RMAs have been implemented, the licensee may delay the 8

required start of the shutdown up to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months from the time LCO 3.0.3 was entered. The 9

24-hour CT would allow the licensee to complete repairs, seek regulatory relief, and/or prepare 10 for the shutdown.

11 12 As stated previously, the Maintenance Rule contained in paragraph (a)(4) of 10 CFR 50.65, 13 Requirements for monitoring the effectiveness of maintenance at nuclear power plants, 14 provides:

15 16 Before performing maintenance activities (including but not limited to 17 surveillance, post-maintenance testing, and corrective and preventive 18 maintenance), the licensee shall assess and manage the increase in risk that 19 may result from the proposed maintenance activities. The scope of the 20 assessment may be limited to structures, systems, and components that a risk-21 informed evaluation process has shown to be significant to public health and 22 safety. [Emphasis added]

23 24 In accordance with the Maintenance Rule, the requirement to assess and manage risk prior to 25 conducting maintenance is necessary in order to restore TS SSCs to operability. Accordingly, 26 the TSTF-585 proposal to assess and manage risk is consistent with the requirements of the 27 Maintenance Rule. To assess the risk, TSTF-585 proposes the use of NUMARC 93-01, 28 Methodology for Assessment and Management of Risk. This guidance was endorsed by the 29 NRC in RG 1.160, as an acceptable method for complying with the provisions of 10 CFR 30 50.65, subject to the clarifications provided in the RG. Since most all of the prior LCO 3.0.3 31 entries occurred due to a loss of a TS safety function, and the NUMARC guidance is being used 32 to determine the acceptability of continued operation in this condition, the NRC staff reviewed 33 the guidance to ensure that the risk assessments would include all appropriate considerations 34 necessary for determining the acceptability of continued operation.

35 36 The NRC staff found that TSTF-585 highlights key guidance on the use of NUMARC 93-01 37 necessary for performing a risk assessment and implementing RMAs, stating:

38 39 The TS Bases clarify that all relevant elements of the NUMARC 93-01 Section 11 40 guidance will be included in the risk assessment.

41 The risk assessment must consider all inoperable equipment regardless of whether the 42 equipment is included in the normal 10 CFR 50.65(a)(4) risk assessment scope.

43 If the extent of condition is unknown, the risk assessment should consider the possibility 44 of common cause failure either numerically or through risk management actions.

45 The risk assessment must consider emergent conditions, such as inoperable equipment 46 due to failures, or significant changes in external conditions (weather, offsite power 47 availability). The risk assessment must also consider internal events, internal floods, and 48 internal fires.

49 Risk management actions include planning and conducting plant activities in a manner 1

that controls overall risk, increased risk awareness by shift and management personnel, 2

and actions to minimize the magnitude of risk increases (establishment of backup success 3

paths or compensatory measures).

4 Risk assessment and risk management actions consider the activities required to restore 5

the inoperable equipment, such as jumpering terminals, lifting leads, placing temporary 6

lead shielding on pipes and equipment, removal of barriers, and use of temporary blocks, 7

bypasses, scaffolding and supports.

8 9

The NRC staff finds that compliance with the NUMARC 93-01 guidance and the above 10 highlighted considerations in TSTF-585 will ensure that the risk assessments conducted under 11 the proposed LCO 3.0.3 will accurately assess the current plant risk (e.g., include all factors 12 relevant to the current plant risk). In addition, compliance with the guidance will ensure that 13 appropriate RMAs will be implemented.

14 15 As stated in the proposed Bases for TSTF-585, [w]henever practicable, a quantitative value for 16 risk shall be determined. Section 3.2.2 of TSTF-585 includes additional details on the meaning 17 of practicable, indicating that circumstances where a licensee would be unable to perform a 18 quantitative risk assessment would be unusual. The traveler also provided examples of 19 situations where performing a qualitative risk assessment may not be practicable. The examples 20 indicate that a qualitative assessment, which is allowed by the guidance in NUMARC 93-01, 21 would most likely be needed: 1) to account for inoperable systems that are not modeled in the 22 probabilistic risk assessment (PRA) or have no effect on core damage (e.g., control room 23 ventilation), 2) when the PRA does not represent the Mode the plant is operating in, or 3) when 24 the necessary computing equipment for a numeric determination is unavailable. Using a 25 quantitative assessment whenever practicable would help ensure consistency across the 26 operating reactor fleet in the application of the LCO 3.0.3 criteria as well as ensure an 27 appropriate level of rigor in performing risk assessments when entering LCO 3.0.3. In addition, if 28 a qualitative assessment were required, TSTF-585 and its associated model application ensure 29 that qualitative risk assessments performed for entries into the proposed LCO 3.0.3 include 30 appropriate levels of rigor (i.e., consider the relevant elements that must be factored into the risk 31 assessment).

32 33 Based on the above evaluation, the NRC staff finds that the risk assessment methodology, as 34 discussed in the submittal, would be acceptable to determine if the proposed risk thresholds are 35 met. Accordingly, the staff concludes that the application of the NUMARC 93-01 methodology 36 as described in TSTF-585 is acceptable for assessing and managing the risk (e.g., identifying 37 appropriate RMAs to be implemented) as required by the proposed LCO 3.0.3.

38 39 3.3 Proposed Action to Require Assessment and Management of Risk Within Six Hours 40 41 The proposed changes to LCO 3.0.3 require the assessment and management of risk within 42 six hours, in lieu of the current requirement of one hour, to prepare to shut down the plant.

43 TSTF-585, Section 3.2.1, Time to Assess and Manage Risk and Implement Risk Management 44 Actions, justifies this proposed change stating, in part:

45 46 Extending the current one-hour delay period to initiate a plant shutdown to six 47 hours5.439815e-4 days 0.0131 hours 7.771164e-5 weeks 1.78835e-5 months is acceptable because the one-hour delay was arbitrary and did not 48 consider the risk associated with a plant shutdown. The proposed six-hour delay 49 provides time to assess the risk significance of the plant conditions and to 50 determine the appropriate actions to take to minimize the impact on plant safety.

51 This change provides greater protection of public health and safety by not 1

requiring a shutdown with inoperable equipment when safer options may be 2

available.

3 4

Section 3.2.1 also provides the technical basis for the associated CT of six hours for assessing 5

and managing risk. Specifically, TSTF-585 states that six hours provides sufficient time to 6

calculate the current risk condition using the plant computer software and to engage the plant 7

PRA staff, if the situation requires their support. In addition, the six-hour CT provides sufficient 8

time to implement a variety of RMAs that may be required depending on the plant situation.

9 Examples of RMAs that may be needed include briefing operating staff, pre-staging FLEX 10 equipment, and bringing additional staff onsite.

11 12 As stated in Section 3.1 of this SE, operating experience supports the conclusion that assessing 13 and managing risk is an appropriate action to be taken when entering LCO 3.0.3. Since 2010, 14 over 88% of the LCO 3.0.3 entries exit within six hours and over 94% exit before a plant 15 shutdown is completed. The historical data shows that repairs are completed before a plant 16 shutdown is completed in the vast majority of LCO 3.0.3 entries, therefore starting a shutdown is 17 not providing an added safety benefit. After risk has been determined to be acceptable, allowing 18 plant staff the ability to focus on managing risk and repairing the inoperable SSCs while the 19 plant is in a stable operating condition reduces risk as compared to working on the repair while 20 the plant is actively shutting down. The NRC staff notes that shutting down the plant while 21 conducting repairs may increase the possibility of introducing a transient while the repairs are 22 ongoing. The staff evaluated the proposed six-hour CT for assessing and managing risk and 23 concluded that this CT duration was reasonable given the variation in plant operating conditions 24 that would need to be considered when assessing the risk and variability of RMAs that may be 25 required to manage risk.

26 27 The NRC staff also evaluated whether the proposed required action to assess and manage risk 28 within six hours before commencing a plant shutdown is reasonable when the risk criteria are 29 not met. The staff found that in cases where the licensee can restore an inoperable system or 30 component and exit LCO 3.0.3, the six-hour CT would avoid unnecessary perturbation of the 31 plant while restoration activities were ongoing. In cases where the licensee would be required to 32 shut down because the risk criteria were not met, then allowing the licensee to implement RMAs 33 would reduce the risk associated with shutting down the plant in a degraded condition (i.e.,

34 without the safety function(s) that caused the entry into LCO 3.0.3). In both cases, the net effect 35 of the required action to assess and manage risk would likely result in the reduction in overall 36 plant risk. Based on the evaluations above, the staff concludes that requiring the assessment 37 and management of risk when entering LCO 3.0.3 with a six-hour CT is acceptable.

38 39 If the risk assessment and management are not completed (i.e., RMAs are not identified and 40 implemented) within six hours of entry into LCO 3.0.3, or if the risk acceptance criteria are not 41 met, or entry into LCO 3.0.3 was planned, then the proposed changes to LCO 3.0.3 would 42 require a shutdown. The times allotted for each mode transition while shutting down following 43 the six-hour permitted time are consistent with the current LCO 3.0.3 CT requirements, just 44 without the one-hour preparation time. The proposed CTs for each mode transition simply 45 reflect the greater time allowed to start the shutdown (i.e., six hours) than is allowed to start the 46 shutdown in the current LCO 3.0.3 (i.e., one hour). Once the shutdown is started, the total time 47 to complete the shutdown is unchanged from the current LCO 3.0.3 CTs. Accordingly, the staff 48 NRC concludes that the proposed changes to LCO 3.0.3 to require the assessment and 49 management of risk within six hours are acceptable.

50 51 3.4 Proposed 24-Hour Completion Time 1

2 If risk is assessed and managed within the first six hours of entry into LCO 3.0.3, and the risk 3

acceptance criteria are met, the proposed change allows a CT of 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months for unplanned entry.

4 The proposed change would extend the current LCO 3.0.3 total CT up to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . Under these 5

circumstances, plant risk, compared to the original LCO 3.0.3 action statement, is potentially 6

impacted since the time limits of the original LCO 3.0.3 will have been exceeded. This is due to 7

the plant operating for a longer period with the equipment inoperable. However, as discussed 8

herein, the NRC staff concluded that the actions required by the proposal in TSTF-585 may 9

generally result in reduced plant risk, and that risk will be managed to an acceptable level.

10 11 3.4.1 Risk Acceptance Criteria 12 13 As indicated above, the proposed change uses the endorsed risk assessment and management 14 method described in NUMARC 93-01, Section 11. TSTF-585 states the following acceptance 15 criteria for determining if continued operation up to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months after entering LCO 3.0.3 is 16 acceptable:

17 18 Continuing operation for a limited time is acceptable if the risk assessment 19 determines that for the current plant configuration, the Incremental Core Damage 20 Probability (ICDP) is less than 1E-5, and the Incremental Large Early Release 21 Probability (ILERP) is less than 1E-6. These limits are consistent with the 22 NUMARC 93-01, Section 11.3.7.2, guidance on configurations that should not 23 normally be entered voluntarily. Consistent with the NUMARC guidance, 24 non-quantifiable factors must also be assessed.

25 26 In addition, the configuration-specific Core Damage Frequency (CDF) and Large 27 Early Release Frequency (LERF) will be evaluated to identify high-risk situations.

28 A configuration-specific CDF in excess of 1E-3/year or LERF in excess of 29 1E-4/year does not support continuing operation.

30 31 Section 11.3.7.2 of NUMARC 93-01 identifies configurations with an ICDP of greater than 1E-5 32 or ILERP greater than 1E-6 as configurations that should not normally be entered voluntarily.

33 Consistent with this guidance, the proposed revision to LCO 3.0.3 does not allow continued 34 operation to conduct maintenance to restore inoperable equipment with these thresholds 35 exceeded (even with RMAs implemented).

36 37 TSTF-585 recognizes that there is a limitation on relying only on ICDP and ILERP. Specifically, 38 because ICDP and ILERP are typically calculated based on the amount of time the plant will be 39 in the configuration of concern, the calculated ICDP and ILERP can be small for a high-risk 40 configuration if the time spent in that configuration is short. Accordingly, TSTF-585 proposes 41 that the configuration-specific CDF (or instantaneous CDF) also be calculated to ensure that the 42 plant is not in a high-risk configuration before allowing the 24-hour CT. Similar to the ICDP 43 Criterion, Section 11.3.7.2 of NUMARC 93-01 does not recommend voluntarily entering plant 44 configurations with a CDF in excess of 1E-3/year. Accordingly, it would not be reasonable to 45 allow continued operation for the purposes of conducting maintenance to restore inoperable 46 SSCs with this CDF limit exceeded, and the proposed changes in TSTF-585 do not allow doing 47 so.

48 49 Based on the above assessment, the NRC staff concludes that the proposed criteria are 1

acceptable for the purpose of determining if the plant can continue operating for up to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months 2

after entering LCO 3.0.3. In addition, the NUMARC 93-01, Section 11, risk assessment and 3

management methodology proposed in TSTF-585 would become part of the plant licensing 4

basis via inclusion in the License Amendment Request to adopt the traveler. Any changes to 5

these requirements would then be subject to the appropriate change control processes 6

(e.g., 10 CFR 50.59), to ensure an appropriate level of regulatory control. The NRC staff also 7

notes that approval of TSTF-585 does not generically endorse the instantaneous risk thresholds 8

for use in other applications.

9 10 3.5 Addition of Explicit Shutdown Requirements 11 12 Industry reviewed the STS to identify conditions that may not be appropriate for either an implicit 13 LCO 3.0.3 entry (i.e., no associated Action for the Condition) or an explicit LCO 3.0.3 entry (i.e.,

14 the Condition directs entry into LCO 3.0.3). Several Conditions were identified in this review. To 15 address this, TSTF-585 proposes providing explicit shutdown actions in the identified LCOs 16 which would then prevent entry into LCO 3.0.3 from occurring. Table 4 below provides the 17 specific changes that are proposed.

18 19 20 Table 4 1

Proposed Revisions Requiring Explicit Shutdown Statements 2

3 4

The NRC staff reviewed the proposed changes described in Table 4 and found that the proposed 5

changes would retain the current requirement to shut down (based on entry into the existing 6

LCO 3.0.3) by preventing the proposed LCO 3.0.3 from applying for the specified Conditions.

7 LCO 3.0.3 would not apply since the proposed revisions described in Table 4 would provide an 8

explicit requirement to shut down in lieu of entry into LCO 3.0.3. Since the technical requirements 9

for these Conditions remains unchanged, the staff finds that the proposed changes are 10 acceptable. Additionally, the NRC staff did not identify any other implicit or explicit entries that 11 would need to be revised to align with the proposed LCO 3.0.3 changes.

12 13 NUREG/Technical Specification Current Required Action Reason for LCO 3.0.3 Entry Proposed Action 1430 / TS 3.1.6, Axial Power Shaping Rod (APSR) Alignment Limits Implicit LCO 3.0.3 Entry No Action for more than one misaligned APSR Modify existing default Action (Condition B) to include a requirement for the plant to be in Mode 3 within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months for Two or more APSRs inoperable, not aligned within their limits, or both.

1431 / TS 3.6.10, Hydrogen Ignition System (HIS)

Implicit LCO 3.0.3 Entry No Action for two HIS trains inoperable Modify existing default Action (Condition C) to include a requirement for the plant to be in Mode 3 within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months for Both HIS trains inoperable OR More than one containment region with no OPERABLE hydrogen ignitor.

1430 through 1432 /

TS 3.7.2, "Main Steam Isolation Valves (MSIVs)"

Implicit LCO 3.0.3 Entry No Action for more than one MSIV inoperable in Mode 1 Modify the existing default Action (Condition B) to include a requirement for the plant to be in Mode 2 within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months for More than one MSIV inoperable in Mode 1.

1430 through 1434 / TS

= 3.8.4, "DC Sources -

Operating" Implicit LCO 3.0.3 Entry No Action for more than one DC electrical power subsystem inoperable A new Condition E is added that requires the plant to be shutdown (i.e., Mode 5 for PWRs and Mode 4 for BWRs) within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months when two DC electrical power subsystems are inoperable.

1430 through 1434 /

TS 3.8.9, "Distribution Systems - Operating" Explicit LCO 3.0.3 Entry Actions direct entry into LCO 3.0.3 when two or more inoperable divisions or subsystems result in a loss of function Action directing entry into LCO 3.0.3 is modified with Actions that require the plant to be shutdown (i.e., Mode 5 for PWRs and Mode 4 for BWRs) within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months for Two or more electrical power distribution subsystems inoperable that result in a loss of function.

3.6 Evaluation of Proposed STS Bases Changes 1

2 As described in Section 2.3 above, TSTF-585 proposes to update the STS Bases and provides a 3

discussion that reflects the revised LCO 3.0.3 structure. The proposed LCO 3.0.3 Bases 4

discussion would also include amplifying details on how the requirement to assess and manage 5

risk would be implemented at an operating plant (i.e., a plant that receives a license amendment 6

approving the adoption of TSTF-585). As required by the proposed LCO 3.0.3, the Bases would 7

be revised to describe the methodology used to assess and manage risk within six hours of entry 8

into LCO 3.0.3 and would provide the risk acceptance criteria used to determine if continued 9

operation up to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months is allowed. Inclusion of this information in the STS Bases is consistent 10 with prior changes made to the STS usage rules. For instance, LCO 3.0.4.b allows Mode 11 changes with an LCO not met so long as the risk has been determined to be acceptable and the 12 RMAs have been established, as appropriate. The Bases for LCO 3.0.4 also provide amplifying 13 details on how the risk assessment is to be performed stating that it must be performed in 14 accordance with RG 1.160 and Section 11 of NUMARC 93-01. Similarly, the Bases for 15 Surveillance Requirement (SR) 3.0.3 stipulate that the risk assessment performed for a missed 16 surveillance should be performed in accordance with RG 1.160.

17 18 Specifying the details of how risk will be assessed and managed in the STS Bases is acceptable 19 because there are regulatory controls on these requirements. Specifically, the Bases Control 20 Program in Section 5.5 of the STS only allows changes to the Bases without prior NRC approval 21 when: 1) the changes do not require a modification to the TSs, or 2) the changes are permitted in 22 accordance with the requirements of 10 CFR 50.59. In addition, the NUMARC 93-01, Section 11, 23 risk assessment and management methodology proposed in TSTF-585 would become part of 24 the plant licensing basis via inclusion in the License Amendment Request to adopt the traveler.

25 Any changes to these requirements would then be subject to the appropriate change control 26 processes (e.g., 10 CFR 50.59) to ensure an appropriate level of regulatory control.

27 28 Upon approval of the traveler, the STS Bases changes proposed in TSTF-585 will be included in 29 the next revision of the NRCs STS Bases NUREG documents. Accordingly, the NRC staff 30 assessed the proposed Bases changes included in TSTF-585 to determine if they are consistent 31 with the guidance in the Commissions Final Policy Statement on Technical Specifications 32 Improvements for Nuclear Power Reactors described in Section 2.0 of this SE.

33 34 The Commissions Final Policy Statement on Technical Specifications Improvements for 35 Nuclear Power Reactors, describes the scope and purpose of the STS Bases. Specifically, it 36 lists five questions the STS Bases must address. While the STS Bases as a whole must address 37 these questions, not every question will be relevant to every change to the STS Bases.

38 39 The first Policy Statement question requires a justification for the TS. This question is addressed 40 by the Bases identifying the 10 CFR 50.36(c)(2)(ii) criterion that applies to LCO 3.0.3.

41 42 The second Policy Statement question ensures that the basis for each LCO is described (i.e.,

43 why the LCO was determined to be the lowest functional capability or lowest performance level 44 for the system or component to ensure safe operation of the facility and, what are the reasons for 45 the applicability of the LCO). LCO 3.0.3 is part of the use and application rules for TS. As such, it 46 does not provide requirements for specific TS SSCs. The LCO 3.0.3 Bases are consistent with 47 the Policy Statement in that they describe the purpose and applicability of LCO 3.0.3.

48 49 The third Policy Statement question asks that the Bases for each Action be described, (i.e., why 50 should this remedial Action be taken if the associated LCO cannot be met; how does this Action 51 relate to other Actions associated with the LCO; and what justifies continued operation of the 1

system or component at the reduced state from the state specified in the LCO for the allowed 2

time period). The staff reviewed the proposed LCO 3.0.3 Bases and determined that they are 3

expanded to adequately describe the actions required when the proposed LCO 3.0.3 is entered 4

and how it justifies continued operation. The Bases of the other affected TS Actions described in 5

Section 4.5 of this SE are revised to describe why the Actions are appropriate for the condition.

6 7

The fourth and fifth Policy Statement questions are not relevant to TSTF-585 because they are 8

related to the Bases for safety limits and SRs. The proposed changes do not affect the safety 9

limits or SRs.

10 11 Based on the above evaluation, the proposed revisions to the STS Bases are consistent with the 12 Commissions Final Policy Statement on Technical Specifications Improvements for Nuclear 13 Power Reactors, and are consistent with 10 CFR 50.36 because the STS Bases changes 14 adequately address the applicable Policy Statement Guidance questions.

15 16 3.7 Reactor Oversight Process (ROP) Follow Up on LCO 3.0.3 Related Events 17 18 The NRC staff evaluated whether the NRC could maintain the appropriate level of oversight for 19 the proposed LCO 3.0.3 revision. Typically, licensees notify the Resident Inspectors Office 20 directly when they have entered into LCO 3.0.3. In addition, the Resident Inspectors frequently 21 review the control room logs. Accordingly, the Resident Inspectors will continue to have the 22 opportunity to be aware of and follow up on the actions taken by the licensee after entering 23 LCO 3.0.3.

24 25 TSTF-585 states, The determination that continuing operation is acceptable will be documented 26 in sufficient detail to allow a knowledgeable individual to understand the basis for the 27 determination. This documentation will also ensure that the Resident Inspectors can evaluate 28 the licensees response to each LCO 3.0.3 entry. The following inspection procedures would 29 support the Resident Inspector inspection/event follow up of an event involving entry into the 30 proposed LCO 3.0.3:

31 32 Inspection Procedure 71153, Follow Up of Events and Notices of Enforcement 33 Discretion 34 Inspection Procedure 71111.13, Maintenance Risk Assessments and Emergent Work 35 Control 36 37 Based on the application of these oversight and inspection procedures, the NRC staff concludes 38 that the NRCs ability to conduct oversight of the revised LCO 3.0.3 under the ROP would be 39 unchanged by the proposed revisions. Accordingly, the proposed changes provide for an 40 acceptable level of oversight.

41 42 3.8 Compliance with 10 CFR 50.36 43 44 Of importance, 10 CFR 50.36(c)(2)(i) states, Limiting conditions for operation are the lowest 45 functional capability or performance levels of equipment required for safe operation of the 46 facility. When an LCO of a nuclear reactor is not met, the licensee shall shut down the reactor or 47 follow any remedial action permitted by the technical specifications until the condition can be 48 met. LCO 3.0.3 implements this regulation by requiring a plant to shut down when an LCO is 49 not met and either: 1) the TS Required Actions are not met, or 2) the TS does not provide any 50 Required Actions for the plant condition. The regulation does not provide any requirements 51 regarding the timing of a required shutdown, and the regulation allows for remedial actions to be 1

provided in TS. Based on the evaluations above, the proposed LCO 3.0.3 would provide 2

appropriate remedial actions in lieu of requiring an immediate shutdown. The proposed 3

LCO 3.0.3 would ensure that appropriate remedial actions are provided for the requested CT of 4

up to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months and the appropriate time for remedial actions are provided based on the risk 5

assessment result. If the required systems are not restored to operable status within the 6

specified CT, a shutdown is required. The NRC staff concludes that the proposed revision to 7

LCO 3.0.3 would continue to meet the requirements of 10 CFR 50.36 and is, therefore, 8

acceptable.

9 10 3.9 Formatting of Proposed STS Change 11 12 The NRC staff reviewed the format and content of the proposed change to STS in TSTF-585 13 and determined that the change is consistent with conventional terminology and complies with 14 the format and usage rules embodied in the STS.

15 16

4.0 CONCLUSION

17 18 The NRC staff reviewed traveler TSTF-585, which proposed changes to STS found in 19 NUREGs-1430, -1431, -1432, -1433, and -1434. The NRC staff determined that the proposed 20 changes to the STS meet 10 CFR 50.36 and the Commissions Final Policy Statement on 21 Technical Specifications Improvements for Nuclear Power Reactors. Additionally, the NRC staff 22 reviewed the changes to the STS and found them to be technically clear and consistent with 23 customary terminology and format in accordance with SRP Chapter 16.0. The NRC staff 24 reviewed the proposed changes to the actions required by LCO 3.0.3 and concluded that the 25 changes provide reasonable assurance of adequate protection of the health and safety of the 26 public. Therefore, the NRC staff concludes that the proposed STS changes are acceptable.

27 28

5.0 REFERENCES

29 30 Traveler TSTF-585, Revision 5, Revise LCO 3.0.3 to Require Managing Risk, dated 31 September 17, 2025 (ML25260A487) 32 NEI, NUMARC 93-01, Revision 4F, Industry Guideline for Monitoring the Effectiveness 33 of Maintenance at Nuclear Power Plants, dated April 2018 (ML18120A069) 34 RG 1.160, Revision 4, Monitoring the Effectiveness of Maintenance at Nuclear Power 35 Plants, dated August 2018 (ML18220B281) 36 RG 1.174, Revision 3, An Approach for Using Probabilistic Risk Assessment in 37 Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis, dated 38 January 2018 (ML17317A256) 39 RG 1.177, Revision 2, An Approach for Plant-Specific, Risk-Informed Decisionmaking:

40 Technical Specifications, dated January 2021 (ML20164A034) 41 U.S. NRC. Commission Paper SECY-93-067, "Final Policy Statement on Technical 42 Specifications Improvements," March 17, 1993 43 44 45 Principal Contributors: R. Elliott, NRR/DSS 46 J. Hughey, NRR/DRA 47 48 Date: December 23, 2025 49

v t e Letter Sequence Draft Approval
EPID:L-2023-PMP-0000, TSTF-585 (Open)
Initiation Request, Request Acceptance, Acceptance Administration Meeting, Meeting Questions Answers Results Approval... Other: ML24302A210, ML24318B831, ML25219A024
MONTHYEAR2024-12-11 [Table View]

ML25335A206