ML17116A032

Issuance of Amendment No. 212 to Adopt Technical Specifications Task Force-427, Allowance for Non-Technical Specification Barrier Degradation on Supported System Operability (CAC No. MF8692.)

ML17116A032
Person / Time
Site:	Grand Gulf
Issue date:	06/07/2017
From:	Siva Lingam Special Projects and Process Branch
To:	Entergy Operations
Lingam S, 301-415-1564
References
CAC MF8692
Download: ML17116A032 (28)

Text

Vice President, Operations Entergy Operations, Inc.

Grand Gulf Nuclear Station P.O. Box 756 Port Gibson, MS 39150 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 June 7, 201 7

SUBJECT:

GRAND GULF NUCLEAR STATION, UNIT 1 - ISSUANCE OF AMENDMENT TO ADOPT TECHNICAL SPECIFICATIONS TASK FORCE (TSTF)-427, REVISION 2, "ALLOWANCE FOR NON TECHNICAL SPECIFICATION BARRIER DEGRADATION ON SUPPORTED SYSTEM OPERABILITY" (CAC NO. MF8692)

Dear Sir or Madam:

The U.S. Nuclear Regulatory Commission (NRC) has issued the enclosed Amendment No. 212 to Renewed Facility Operating License No. NPF-29 for the Grand Gulf Nuclear Station, Unit 1.

The amendment consist of changes to the Technical Specifications (TSs) in response to your application dated October 26, 2016.

The amendment revises TS requirements for unavailable barriers by adding new Limiting Condition for Operation (LCO) 3.0.9. The LCO allows a delay time for entering a supported system TS, when the inoperability is solely due to an unavailable barrier, if the risk is assessed and managed. The postulated initiating events, which may require a functional barrier, are limited to those with low frequencies of occurrence, and the overall TS system safety function would still be available for the majority of anticipated challenges.

This amendment is consistent with NRG-approved Technical Specification Task Force (TSTF)

Improved Standard Technical Specifications Change Traveler, TSTF-427, Revision 2, "Allowance for Non Technical Specification Barrier Degradation on Supported System OPERABILITY."

A copy of our related Safety Evaluation is also enclosed. The Notice of Issuance will be included in the Commission's next biweekly Federal Register notice.

Docket No. 50-416

Enclosures:

1. Amendment No. 212 to NPF-29

2. Safety Evaluation cc w/encls: Distribution via Listserv Sincerely,

~~*~

Siva P. Lingam, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 ENTERGY OPERATIONS, INC.

SYSTEM ENERGY RESOURCES. INC.

SOUTH MISSISSIPPI ELECTRIC POWER ASSOCIATION ENTERGY MISSISSIPPI, INC.

DOCKET NO. 50-416 GRAND GULF NUCLEAR STATION. UNIT 1 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 212 Renewed License No. NPF-29

1.

The Nuclear Regulatory Commission (the Commission) has found that:

A.

The application for amendment by Entergy Operations, Inc. (the licensee), dated October 26, 2016, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I; B.

The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C.

There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D.

The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.

The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.

2.

Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.C.(2) of Renewed Facility Operating License No. NPF-29 is hereby amended to read, in part, as follows:

(2)

Technical Specifications The Technical Specifications contained in Appendix A and the Environmental Protection Plan contained in Appendix B, as revised through Amendment No. 212 are hereby incorporated into this renewed license. Entergy Operations, Inc. shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.

3.

This license amendment is effective as of its date of issuance and shall be implemented within 90 days from the date of issuance.

Attachment:

Changes to the Renewed Facility Operating License No. NPF-29 and the Technical Specifications Date of Issuance: June 7, 201 7 FOR THE NUCLEAR REGULA TORY COMMISSION Robert J. Pascarelli, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

ATTACHMENT TO LICENSE AMENDMENT NO. 212 RENEWED FACILITY OPERATING LICENSE NO. NPF-29 GRAND GULF NUCLEAR STATION. UNIT 1 DOCKET NO. 50-416 Replace the following pages of the Renewed Facility Operating License No. NPF-29 and the Appendix A, Technical Specifications with the attached revised pages. The revised pages are identified by amendment number and contain marginal lines indicating the areas of change.

Facility Operating License Remove Insert Technical Specifications Remove 3.0-1 3.0-3 Insert 3.0-1 3.0-3 3.0-3a

amended, are fully applicable to the lessors and any successors in interest to those lessors, as long as the renewed license of GGNS Unit 1 remains in effect.

(b)

SERI is required to notify the NRG in writing prior to any change in (i) the terms or conditions of any new or existing sale or lease agreements executed as part of the above authorized financial transactions, (ii) the GGNS Unit 1 operating agreement, (iii) the existing property insurance coverage for GGNS Unit 1 that would materially alter the representations and conditions set forth in the.

Staff's Safety Evaluation Report dated December 19, 1988 attached to Amendment No. 54. In addition, SERI is required to notify the NRG of any action by a lessor or other successor in interest to SERI that may have an effect on the operation of the facility.

C.

The renewed license shall be deemed to contain and is subject to the conditions specified in the Commission's regulations set forth in 10 CFR Chapter I and is subject to all applicable provisions of the Act and to the rules, regulations, and orders of the Commission now or hereafter in effect; and is subject to the additional conditions specified or incorporated below:

(1)

Maximum Power Level Entergy Operations, Inc. is authorized to operate the facility at reactor core power levels not in excess of 4408 megawatts thermal (100 percent power) in accordance with the conditions specified herein.

(2)

Technical Specifications The Technical Specifications contained in Appendix A and the Environmental Protection Plan contained in Appendix B, as revised through Amendment No. 212 are hereby incorporated into this renewed license. Entergy Operations, Inc. shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.

During Cycle 19, GGNS will conduct monitoring of the Oscillation Power Range Monitor (OPRM). During this time, the OPRM Upscale function (Function 2.f of Technical Specification Table 3.3.1.1-1) will be disabled and operated in an "indicate only" mode and technical specification requirements will not apply to this function. During such time, Backup Stability Protection measures will be implemented via GGNS procedures to provide an alternate method to detect and suppress reactor core thermal hydraulic instability oscillations. Once monitoring has been successfully completed, the OPRM Upscale function will be enabled and technical specification requirements will be applied to the function; no further operating with this function in an "indicate only" mode will be conducted.

4 Amendment No. 212

LCO Applicability 3.0 3.0 LIMITING CONDITION FOR OPERATION (LCO) APPLICABILITY LCO 3.0.1 LCO 3.0.2 LCO 3.0.3 LCO 3.0.4 GRAND GULF LCOs shall be met during the MODES or other specified conditions in the Applicability, except as provided in LCO 3.0.2, LCO 3.0.7, LCO 3.0.8, and LCO 3.09.

Upon discovery of a failure to meet an LCO, the Required Actions of the associated Conditions shall be met, except as provided in LCO 3.0.S and LCO 3.0.6.

If the LCO is met or is no longer applicable prior to expiration of the specified Completion Time(s), completion of the Required Action(s) is not required, unless otherwise stated.

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 <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> to place the unit, as applicable, in:

a.

MODE 2 within 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />;

b.

MOOE 3 within 13 hours1.50463e-4 days <br />0.00361 hours <br />2.149471e-5 weeks <br />4.9465e-6 months <br />; and

c.

MODE 4 within 37 hours4.282407e-4 days <br />0.0103 hours <br />6.117725e-5 weeks <br />1.40785e-5 months <br />.

Exceptions to this Specification are stated in the individual Specifications.

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.

LCO 3.0.3 is only applicable in MODES 1, 2, and 3.

When an LCO is not met, entry into a MODE or other specified condition in the Applicability shall only be made:

a.

When the associated ACTIONS to be entered permit continued operation in the MODE or other specified condition in the Applicability for an unlimited period of time; (continued) 3.0-1 Amendment No. 1:T3:, ~

212

LCO Applicability 3.0 3.0 LCO APPLICABILITY (continued)

LCO 3.0.7 LCO 3.0.8 LCO 3.0.9 GRAND GULF Special Operations LCOs in Section 3.10 allow specified Technical Specifications (TS) requirements to be changed to permit performance of special tests and operations.

Unless otherwise specified, all other TS requirements remain unchanged.

Compliance with Special Operations LCOs is optional.

When a Special Operations LCO is desired to be met but is not met, the ACTIONS of the Special Operations LCO shall be met.

When a Special Operations LCO is not desired to be met, entry into a MODE or other specified condition in the Applicability shall only be made in accordance with the other applicable Specifications.

When one or more required snubbers are unable to perform their associated support function(s), any affected supported LCO(s) are not required to be declared not met solely for this reason if risk is assessed and managed, and:

a.

the snubbers not able to perform their associated support function(s) are associated with only one train or subsystem of a multiple train or subsystem supported system or are associated with a single train or subsystem supported system and are able to perform their associated support function within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />; or

b.

the snubbers not able to perform their associated support function(s) are associated with more than one train or subsystem of a multiple train or subsystem supported system and are able to perform their associated support function within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

At the end of the specified period the required snubbers must be able to perform their associated support function(s), or the affected supported system LCO(s) shall be declared not met.

When one or more required barriers are unable to perform their related support function(s), any supported system LCO(s) are not required to be declared not met solely for this reason for up to 30 days provided that at least one train or subsystem of the supported system is OPERABLE and supported by barriers capable of providing their related support function(s), and risk is assessed and managed. This specification may be concurrently applied to more than one train or subsystem of a multiple train or subsystem supported system provided at least one train or subsystem (continued) 3.0-3 Amendment No.~,4-74,212

LCO Applicability 3.0 3.0 LCO APPLICABILITY LCO 3.0.9 (continued)

GRAND GULF of the supported system is OPERABLE and the barriers supporting each of these trains or subsystems provide their related support function(s) for different categories of initiating events.

For the purposes of this specification, the High Pressure Core Spray system, the Reactor Core Isolation Cooling system, and the Automatic Depressurization System are considered independent subsystems of a single system.

If the required OPERABLE train or subsystem becomes inoperable while this specification is in use, it must be restored to OPERABLE status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or the provisions of this specification cannot be applied to the trains or subsystems supported by the barriers that cannot perform their related support function(s).

At the end of the specified period, the required barriers must be able to perform their related support function(s) or the supported system LCO(s) shall be declared not met.

(continued) 3.0-3a Amendment No. 2..12

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 212 TO RENEWED FACILITY OPERATING LICENSE NO. NPF-29

1.0 INTRODUCTION

ENTERGY OPERATIONS, INC., ET AL.

GRAND GULF NUCLEAR STATION. UNIT 1 DOCKET NO. 50-416 By application dated October 26, 2016 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML16301A150), Entergy Operations, Inc. (the licensee),

requested changes to the Technical Specifications (TSs) for the Grand Gulf Nuclear Station, Unit 1 (Grand Gulf).

The proposed changes would revise TS requirements for unavailable barriers by adding new Limiting Condition for Operation (LCO) 3.0.9. The LCO allows a delay time for entering a supported system TS, when the inoperability is solely due to an unavailable barrier, if the risk is assessed and managed. The postulated initiating events, which may require a functional barrier, are limited to those with low frequencies of occurrence, and the overall TS system safety function would still be available for the majority of anticipated challenges. This amendment is consistent with U.S. Nuclear Regulatory Commission (NRC)-approved Technical Specification Task Force (TSTF) Improved Standard Technical Specifications (STS) Change Traveler, TSTF-427, Revision 2, "Allowance for Non Technical Specification Barrier Degradation on Supported System OPERABILITY" (ADAMS Accession No. ML061240055).

2.0 REGULATORY EVALUATION

In Title 1 O of the Code of Federal Regulations (1 O CFR) Section 50.36, the Commission established its regulatory requirements related to the content of TSs. Pursuant to 1 O CFR 50.36, TSs are required to include items in the following five specific categories related to station operation: (1) safety limits, limiting safety system settings, and limiting control settings; (2) LCOs; (3) surveillance requirements (SRs); (4) design features; and (5) administrative controls. The rule does not specify the particular requirements to be included in a plant's TSs. As stated, in part, in 10 CFR 50.36(c)(2) (i), the "Limiting conditions for operation are the lowest functional capability or performance levels of equipment required for safe operation of the facility. When a limiting condition for operation of a nuclear reactor is not met, the licensee shall shut down the reactor or follow any remedial action permitted by the technical specifications.... " Grand Gulf TS Section 3.0 for "LCO and SR Applicability," provides details or ground rules for complying with the LCOs.

Barriers are doors, walls, floor plugs, curbs, hatches, installed structures or components, or other devices, not explicitly described in TSs that support the performance of the functions of systems described in the TSs. For purposes of this TS LCO, the term "barrier" refers to one or more devices which protect one train of a safety system from a given initiating event. A "degraded barrier" refers to a barrier that has been found to be degraded and must be repaired, or to a barrier that is purposefully removed or reconfigured to facilitate maintenance activities.

As stated in Nuclear Energy Institute (NEI) 04-08, "Risk-Informed Technical Specifications Initiative 7a, Allowance for Non-Technical Specification Barrier Degradation on Supported System Operability (TSTF-427), Industry Implementation Guidance," March 2006 (ADAMS Accession No. ML061220426), LCO 3.0.9 specifically does not apply to fire barriers, snubbers, barriers which support ventilation systems or non-TS systems, or barriers, which support TS systems where the unavailability of the barrier does not render the supported system inoperable.

Some TS-required systems may require one or more functional barriers in order to perform their intended function(s) for certain initiating events for which the barriers provide some protective support function. For example, there are barriers to protect systems from the effects of internal flooding, such as floor plugs and retaining walls, and barriers are used to protect equipment from steam impingement in case of high energy line breaks. Barriers are also used to protect systems against missiles, either internally generated, or generated by external events.

The Grand Gulf TSs do not explicitly describe barriers, but require barriers to be capable of performing their support function by the definition of OPERABILITY for the supported system.

Therefore, under the current STS, the supported system must be declared inoperable when the related barrier(s) are unavailable. However, the magnitude of plant risk associated with the barrier, which cannot perform its related support function, is much less than the risk associated with direct unavailability of the supported system, since barriers are only required for specific, low frequency initiating events.

Some potential undesirable consequences of the current Grand Gulf TS requirements include:

1.

When maintenance activities on the supported TS system require removal and restoration of barriers, the time available to complete maintenance and perform system restoration and testing is reduced by the time spent maneuvering the barriers within the time constraints of the supported system LCO;

2.

Restoration of barriers following maintenance may be given a high priority due to time restraints of the existing supported system LCO, when other activities may have a greater risk impact and should therefore be given priority; and

3.

Unnecessary plant shutdowns may occur due to discovery of degraded barriers, which require more time than provided by the existing supported system LCO to complete repairs and restoration of the barrier.

To improve the treatment of unavailable barriers and enhance safety, the TSTF proposed a risk-informed TS change that introduces a delay time before entering the actions for the supported equipment, when one or more barriers are found to be degraded, or are removed or reconfigured to support maintenance activities, if risk is assessed and managed. Such a time delay will provide needed flexibility in the performance of maintenance and at the same time will enhance overall plant safety by:

1.

Performing system maintenance and restoration activities, including post-maintenance testing, within the existing TS LCO time, and allowing barrier removal and restoration to be performed outside of the TS LCO, providing more time for the safe conduct of maintenance and testing activities on the supported TS system;

2.

Requiring barrier removal and restoration activities to be assessed and prioritized based on actual plant risk impacts; and

3.

Avoiding unnecessary unscheduled plant shutdowns and thus minimizing plant transition and realignment risks.

NRC guidance about risk informed evaluations in Regulatory Guide (RG) 1.17 4, "An Approach for Using Probabilistic Risk Assessment in Risk Informed Decisions on Plant Specific Changes to the Licensing Basis," July 1998 (ADAMS Accession No. ML003740133), and RG 1.177, "An Approach for Plant Specific, Risk Informed Decisionmaking: Technical Specifications," dated August 1998 (ADAMS Accession No. ML003740176).

3.0 TECHNICAL EVALUATION

3.1 Proposed TS Change The proposed TS change would add a new LCO 3.0.9 to the TSs. LCO 3.0.9 would allow the licensee to delay declaring an LCO not met for equipment supported by barriers unable to perform their associated support function, when risk is assessed and managed. TS LCO 3.0.9 states:

When one or more required barriers are unable to perform their related support function(s), any supported system LCO(s) are not required to be declared not met solely for this reason for up to 30 days provided that at least one train or subsystem of the supported system is OPERABLE and supported by barriers capable of providing their related support function(s), and risk is assessed and managed. This specification may be concurrently applied to more than one train or subsystem of a multiple train or subsystem supported system provided at least one train or subsystem of the supported system is OPERABLE and the barriers supporting each of these trains or subsystems provide their related support function(s) for different categories of initiating events.

For the purposes of this specification, the High Pressure Core Spray system, the Reactor Core Isolation Cooling system, and the Automatic Depressurization System are considered independent subsystems of a single system.

If the required OPERABLE train or subsystem becomes inoperable while this specification is in use, it must be restored to OPERABLE status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or the provisions of this specification cannot be applied to the trains or subsystems supported by the barriers that cannot perform their related support function(s).

At the end of the specified period, the required barriers must be able to perform their related support function(s) or the supported system LCO(s) shall be declared not met.

In addition, LCO 3.0.9 would be added to the list of LCOs in LCO 3.0.1.

3.2 Background

The industry submitted TSTF-427, Revision 2, in support of the proposed TS change. This submittal documents a risk-informed analysis of the proposed TS change. Probabilistic risk assessment (PRA) methods are used, in combination with deterministic and defense-in-depth arguments, to identify and justify delay times for entering the actions for the supported equipment associated with unavailable barriers at nuclear power plants. The industry also submitted implementation guidance NEI 04-08. This submittal provides detailed guidance on assessing and managing risk associated with unavailable barriers. This is in accordance with guidance provided in Regulatory Guide (RG) 1.17 4, "An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis,"

July 1998 (ADAMS Accession No. ML003740133) and RG 1.177, "An Approach for Plant-Specific Risk-Informed Decisionmaking: Technical Specifications," August 1998 (ADAMS Accession No. ML003740176).

The risk impact associated with the proposed delay times for entering the TS actions for the supported equipment can be assessed using the same approach as for allowed Completion Time (CT) extensions. Therefore, the risk assessment was performed following the three-tiered approach recommended in RG 1.177 for evaluating proposed extensions in currently allowed CTs:

1.

The first tier involves the assessment of the change in plant risk due to the proposed TS change. Such risk change is expressed (1) by the change in the average yearly core damage frequency (L'.lCDF) and the average yearly large early release frequency (L'.lLERF), and (2) by the incremental conditional core damage probability (ICCDP) and the incremental conditional large early release probability (ICLERP). The assessed L'.lCDF and L'.lLERF values are compared to acceptance guidelines, consistent with the Commission's Safety Goal Policy Statement as documented in RG 1.17 4, so that the plant's average baseline risk is maintained within a minimal range. The assessed ICCDP and ICLERP values are compared to acceptance guidelines in RG 1.177, which provide assurance that the plant risk does not increase unacceptably during the period the equipment is taken out of service.

2.

The second tier involves the identification of potentially high-risk configurations that could exist if equipment in addition to that associated with the change were to be taken out of service simultaneously, or other risk-significant operational factors such as concurrent equipment testing were also involved. The objective is to ensure that appropriate restrictions are in place to avoid any potential high-risk configurations.

3.

The third tier involves the establishment of an overall Configuration Risk Management Program (CRMP) to ensure that potentially risk-significant configurations resulting from maintenance and other operational activities are identified. The objective of the CRMP is to manage configuration-specific risk by appropriate scheduling of plant activities and/or appropriate compensatory measures.

A simplified risk assessment was performed to justify the proposed addition of LCO 3.0.9 to the Grand Gulf's TSs. This approach was necessitated by (1) the general nature of the proposed TS change (i.e., it applies to all plants and is associated with an undetermined number of barriers that are not able to perform their function), and (2) the lack of detailed modeling in most plant-specific PRAs which do not include passive structures such as barriers.

The simplified risk assessment considers three different parameters:

1.

The length of time the affected barrier is unavailable,

2.

The initiating event frequency for which the affected barrier is designed to mitigate, and

3.

The importance to CDF (or LERF) of the TS equipment (train, subsystem, or component) for which the affected barrier is designed to protect, measured by the risk achievement worth (RAW) of the equipment.

The ICCDP can be calculated based on the following equation:

ICCDP ~ [ 8~~6 x :: ; ] x [(RAW 1 x CDF,,"" )- CDF'""'"]

Where:

Tc is the time the barrier is unavailable (hours)

T cf8766 is therefore the fraction of the year during which the barrier is unavailable, IE/IET is the ratio of the initiating event frequency for which the affected barrier is designed to mitigate, IE, and the total initiating event frequency, IET, RAWi is the risk achievement worth of the component(s) for which the barrier provides protection, and CDFbase is the baseline CDF (per year).

ICLERP also may be similarly determined, using baseline LERF and RAW values with respect to LERF. It is assumed that the magnitude of the LERF risk resulting from the barrier unable to perform its related support function would be generally at least one order of magnitude less than the corresponding CDF risk. Containment bypass scenarios, which are typically the significant contributors to LERF, would not be uniquely affected by application of LCO 3.0.9, and initiating events which would be significant LERF contributors, such as steam generator tube rupture and interfacing systems loss-of-coolant accident (LOCA), are not typically associated with barriers within the scope of LCO 3.0.9. Therefore, the assumption regarding LERF risk is reasonable and acceptable for the generic risk evaluation, provided that LERF risk impacts are considered on a plant-specific basis for unavailable barriers, as described in Section 3.3.3 of this SE.

The relevant initiating events (i.e., events for which barriers subject to LCO 3.0.9 provide protection) are:

internal and external floods, high energy line breaks, feedwater line breaks, LOCA (small, medium, and large),

tornados and high winds, and turbine missiles.

Generic frequencies for most of these initiating events were obtained from NUREG/CR-5750, "Rates of Initiating Events at U.S. Nuclear Power Plants: 1987 - 1995," February 1999 (ADAMS Accession No. ML070580080). For external floods, turbine missiles, and tornados, other industry source documents were referenced. The most limiting (highest frequency) initiating event was obtained for a high energy line break from NUREG/CR-5750, with a frequency of 9.1 E-3 per year. The risk assessment is therefore based on this limiting frequency, and the proposed methodology to apply LCO 3.0.9 is similarly restricted to barriers protecting against initiating events whose total frequency is no more than 9.1 E-3 per year.

3.3 Risk Assessment Results and Insights The results and insights from the implementation of the three-tiered approach of RG 1.177 to support the proposed addition of LCO 3.0.9 to the Grand Gulf TSs are summarized and evaluated in the following Sections 3.3.1 to 3.3.3.

3.3.1 Risk Impact The bounding risk assessment approach, described in Section 3.2, was developed for a range of plant baseline CDF values and for a range of protected component RAW values. The maximum allowable 30-day outage time was used. The results are summarized (from TSTF-427, Revision 2) in Table 1.

Table 1. Risk Assessment Results for a Postulated 30-Day Barrier Outage.

B I'

CDF 1E 6 ase1ne

= - per year RAW ICCDP IC LE RP 2

7.5E-10 7.5E-11 10 6.7E-09 6.7E-10 50 3.7E-08 3.7E-09 100 7.4E-08 7.4E-09 B

I' CDF 1E 5 ase 1ne

= - per year RAW ICCDP ICLERP 2

7.5E-09 7.5E-10 10 6.7E-08 6.7E-09 50 3.7E-07 3.7E-08 100 7.4E-07 7.4E-08 B

I' CDF 1E 4 ase1ne

= -

per year RAW ICCDP IC LE RP 2

7.5E-08 7.5E-09 10 6.7E-07 6.7E-08 50 3.7E-06 3.7E-07 100 7.4E-06 7.4E-07 The above results represent a sensitivity analysis covering the expected range of plant baseline CDF values and component RAW values. The most limiting configurations involving very high risk components (RAW > 10) would not be anticipated to occur for most planned maintenance activities.

The calculations conservatively assume the most limiting (highest frequency) initiating event and the longest allowable outage time (30 days). Occurrence of the initiating event during unavailability of the barrier is conservatively assumed to directly fail the protected equipment; no credit is taken for event-specific circumstances which may result in the equipment remaining functional even with the barrier unavailable. (For example, a barrier required to protect equipment from steam impingement for high energy line breaks may only be required for breaks occurring in specific locations and orientations relative to the protected equipment, and only for large size breaks.) No credit is taken for avoided risk identified in Section 2.

The risk assessment results of Table 1 were compared to guidance provided in the revised Section 11 of NUMARC 93-01, Revision 2, "Nuclear Energy Institute Industry Guideline for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants," April 1996 (ADAMS Accession No. ML101020415), endorsed by RG 1.160, Revision 3, "Monitoring the Effectiveness of Maintenance at Nuclear Power Plants," May 2012 (ADAMS Accession No. ML113610098)1, for implementing the requirements of paragraph (a)(4) of the Maintenance Rule, 10 CFR 50.65, "Requirements for monitoring the effectiveness of maintenance at nuclear power plants." Such guidance is summarized in Table 2. Guidance regarding the acceptability of conditional risk increase in terms of CDF for a planned configuration is provided. This guidance states that a specific configuration that is associated with a CDF higher than 1 E-3 per year should not normally be entered voluntarily. The NRC staff notes that the higher risk configurations documented in Table 1 would exceed this guidance and, therefore, would not be permitted to be entered voluntarily. For example, with a baseline CDF of 1 E-4 per year, a component with a RAW greater than 10 would exceed the 1 E-3 per year criteria. Therefore, the sensitivity analyses presented in Table 1 include higher risk configurations, which would not be permitted under the guidance of NUMARC-93-01.

TSTF-427, Revision 2, provides guidance on specific plant configuration associated with ICCDP and ICLERP values, as noted in Table 2 below.

Table 2. Guidance for Implementing 1 O CFR 50.65(a)(4)

LiRcoF Guidance Greater than 1 E-3/year Configuration should not normally be entered voluntarily ICCDP Guidance I CLE RP Greater than 1 E-5 Configuration should not normally be Greater than 1 E-6 entered voluntarily 1 E-6 to 1 E-5 Assess non-quantifiable factors 1E-7 to 1E-6 Establish risk management actions Less than 1 E-6 Normal work controls Less than1 E-7 Guidance regarding the acceptability of ICCDP and ICLERP values for a specific planned configuration and the establishment of risk management actions is also provided in NUMARC 93-01. This guidance, as shown in Table 2, states that a specific plant configuration that is associated with ICCDP and ICLERP values below 1 E-6 and 1 E-7, respectively, is considered to require "normal work controls." Table 1 shows that for the majority of barrier outage configurations, the conservatively assessed ICCDP and ICLERP values are within the limits for what is recommended as the threshold for the "normal work controls" region.

As stated in the implementation guidance for STS LCO 3.0.9 (NEI 04-08), plants are required to commit to the guidance of NUMARC 93-01, Section 11 and, therefore, the above limits would be applicable. Plant configurations including out-of-service barriers may, therefore, be entered voluntarily if supported by the results of the risk assessment required by 10 CFR 50.65(a)(4),

and by LCO 3.0.9.

1 The availability of this TS improvement was published in the Federal Register on October 3, 2006 (71 FR 58444) as part of the Consolidated Line Item Improvement Process and referenced RG 1.182, "Assessing and Managing Risk Before Maintenance Activities at Nuclear Power Plants," May 2000 (ADAMS Accession No. ML003699426). However, RG 1.182 has been superseded by RG 1.160, Revision 3.

RG 1.177 provides guidance of 5E-7 ICCDP and 5E-8 ICLERP as the limit for the TS allowed outage time. As shown in Table 1, the guidance is met for the typically anticipated configurations, unless either the baseline CDF for the plant approaches 1 E-4 per year or the RAW of the protected components is well above 10. Such configurations may exceed the criteria described in NUMARC 93-01 (Table 2) and would not be voluntarily entered. Such configurations are not expected to be frequently encountered, and may be addressed on a case-by-case plant-specific basis by limiting the allowed outage time and by implementing plant-specific risk management actions, as per the implementing guidance of NEI 04-08.

RG 1.17 4 provides guidance of 1 E-5 per year ~CDF and 1 E-6 per year ~LERF. The ICCDP calculations demonstrated that each individual 30-day barrier outage is anticipated to be low risk. Although there is no explicit limit on the number of times per year that LCO 3.0.9 may be applied, even assuming barrier outages occurred continuously over the entire year, the risk incurred would still be anticipated to be below the limits of the guidance.

The NRC staff concludes that the risk assessment results support the proposed addition of LCO 3.0.9 to the Grand Gulf TSs. The risk increases associated with this TS change will be insignificant based on guidance provided in RGs 1.17 4 and 1.177 and within the range of risks associated with normal maintenance activities.

3.3.2 Identification of High-Risk Configurations The second tier of the three-tiered approach recommended in RG 1.177 involves the identification of potentially high-risk configurations that could exist if equipment, in addition to that associated with the TS changes, were to be taken out of service simultaneously. Insights from the risk assessments, in conjunction with important assumptions made in the analysis and defense-in-depth considerations, were used to identify such configurations. To avoid these potentially high-risk configurations, specific restrictions to the implementation of the proposed TS changes were identified.

Under the proposed LCO 3.0.9, at least one train or subsystem is required to be operable with required barriers in place, such that this train or subsystem would be available to provide mitigation of the initiating event. The proposed LCO 3.0.9 applies to multiple trains of the same system only for barriers which provide protection for different initiating events, such that at least one train or subsystem is available to provide mitigation of the initiating event. The use of LCO 3.0.9 for barriers, which protect all trains or subsystems from a particular initiating event, is not permitted because of unavailability of at least one train or subsystem to mitigate the initiating event. Therefore, potentially high-risk configurations involving a loss of function required for mitigation of a particular initiating event are avoided by the restrictions imposed on applicability of LCO 3.0.9.

LCO 3.0.9 also addresses potential emergent conditions where unplanned failures or discovered conditions may result in the unavailability of a required train or subsystem for a particular initiating event. Such conditions may result while operating under LCO 3.0.9 from equipment failure on the operable train, such that all trains of a TS system are not protected from the same initiating event. In such cases, a 24-hour allowed completion time is provided to restore the conditions to permit continued operation with unavailable barriers, after which the applicability of LCO 3.0.9 ends, and the supported system LCO becomes effective. This allowed time is provided so that emergent conditions with low risk consequences may be effectively managed, rather than requiring immediate exit of LCO 3.0.9 and the potential for an unplanned plant shutdown.

LCO 3.0.9 includes a limit of 30 days of allowed outage time for each barrier, after which the barrier must be restored to an available status, or the supported system TS must be applied.

This 30-day backstop applies regardless of the risk level calculated, and provides assurance that installed plant barriers will be maintained available over long periods of time, and that the application of LCO 3.0.9 will not result in long-term degradation of plant barriers.

The NRC staff concludes that the restrictions on the applicability of LCO 3.0.9 assuring that one safety train remains available to mitigate the initiating event, along with the 30-day limit applicable to each barrier, assure that potentially high-risk configurations are avoided in accordance with the guidance provided in RGs 1.17 4 and 1.177.

3.3.3 Configuration Risk Management The third tier of the three-tiered approach recommended in RG 1.177 involves the establishment of an overall CRMP to ensure that potentially risk-significant configurations resulting from maintenance and other operational activities are identified. The objective of the CRMP is to manage configuration-specific risk by appropriate scheduling of plant activities and/or appropriate compensatory measures. This objective is met by licensee programs to comply with the requirements of paragraph (a)(4) of the Maintenance Rule (10 CFR 50.65) to assess and manage risk resulting from maintenance activities, and by LCO 3.0.9 requiring risk assessments and management using (a)(4) processes if no maintenance is in progress. These programs can support licensee decision making regarding the appropriate actions to manage risk whenever a risk-informed TS is entered.

The implementation guidance for LCO 3.0.9 (NEI 04-08) specifies that the allowed outage time determination for an unavailable barrier be performed using the plant-specific configuration.

Further, the risk determinations are to be updated whenever emergent conditions occur. These provisions assure that the configuration-specific risk associated with unavailable barriers is assessed and managed prior to entry into LCO 3.0.9 and during its applicability as conditions change.

These evaluations for the unavailable barrier are performed as part of the assessment of plant risk required by 1 O CFR 50.65(a)(4). The numerical guidance identified in Table 2 is applicable to implementation of LCO 3.0.9, using the results of the configuration-specific risk assessment which addresses the risk impact of the unavailable barrier along with all other out-of-service components and plant alignments.

Risk management actions should be considered when the calculated risk exceeds specific thresholds per NUMARC 93-01, Section 11, as identified in Table 2. Additional guidance on risk management actions are provided in the implementation guidance for LCO 3.0.9.

The allowed outage time for a barrier is calculated based on an ICCDP limit of 1 E-6. This is the NUMARC 93-01, Section 11 guidance for applicability of normal work controls, and is conservatively lower than the guidance of 1 E-5 for voluntary maintenance activities. The use of 1 E-6 will result in conservatively short allowed outage times for barriers compared to allowed times for other maintenance activities.

If the scope of the PRA model used to support the plant-specific CRMP does not include the initiating event for which a barrier provides protection, then LCO 3.0.9 applicability is limited to one barrier on a single train. Multiple barriers for such initiating events may not be unavailable under LCO 3.0.9, and in such situations the LCO(s) associated with the protected components would be applicable. Applicability of LCO 3.0.9 to the single barrier for an initiating event that is not modeled in the plant PRA is acceptable based on the generic risk analysis provided by TSTF-427, as described in Section 3.3 of this SE.

Assessment of the LERF risk impact on an unavailable barrier is required to be performed in accordance with NUMARC 93-01, Section 11. If an unavailable barrier provides protection to equipment which is relevant to the containment function, or which protects equipment from the effects of an initiating event which is a contributor to LERF, then applicability of LCO 3.0.9 must be limited to that one barrier unless a quantified assessment of LERF is performed.

The NRC staff concludes that the risk evaluations necessary to support the applicability of LCO 3.0.9 appropriately consider the risk from unavailable barriers in an integrated manner based on the overall plant configuration. Therefore, potentially high-risk configurations can be identified and managed in accordance with the guidance provided in RGs 1.17 4 and 1.177.

3.4 Summary The unavailability of barriers which protect TS-required components from the effects of specific initiating events is typically a low-risk configuration, which should not require that the protected components be immediately declared inoperable. The current TSs require that when such barriers are unavailable, the protected component LCO is immediately entered. Some potential undesirable consequences of the current TS requirements include:

1.

When maintenance activities on the supported TS system require removal and restoration of barriers, the time available to complete maintenance and perform system restoration and testing is reduced by the time spent maneuvering the barriers within the time constraints of the supported system LCO;

2.

Restoration of barriers following maintenance must be given a high priority due to time restraints of the existing supported system LCO, when other more risk-important activities may have a greater risk impact and should therefore be given priority; and

3.

Unnecessary plant shutdowns may occur due to discovery of degraded barriers which may require more than the existing supported system LCO time to complete repairs and restoration.

To remove the overly restrictive requirements in the treatment of barriers, the licensee proposed a risk-informed TS change which introduces a delay time before entering the actions for the supported equipment when one or more barriers are found degraded or removed to facilitate planned maintenance activities. Such a delay time will provide needed flexibility in the performance of maintenance during power operation and at the same time will enhance overall plant safety by (1) performing system maintenance and restoration activities, including post-maintenance testing, within the existing TS LCO time, and allowing barrier removal and restoration to be performed outside of the TS LCO, providing more time for the safe conduct of maintenance and testing activities on the supported system; (2) requiring barrier removal and restoration activities to be assessed and prioritized based on actual plant risk impacts; and (3) avoiding unnecessary unscheduled plant shutdowns, thus minimizing plant transition and realignment risks.

The risk impact of the proposed TS changes was assessed following the three-tiered approach recommended in RG 1.177. A simplified bounding risk assessment was performed to justify the proposed TS changes. This bounding assessment was selected due to the lack of detailed plant-specific risk models for most plants which do not include failure modes of passive structures such as barriers. The impact from the addition of the proposed LCO 3.0.9 to the TSs on defense-in-depth was also evaluated in conjunction with the risk assessment results.

Based on this integrated evaluation, which is bounding for Grand Gulf, the NRC staff concludes that the proposed addition of LCO 3.0.9 to the plant's TSs would lead to insignificant risk increases as stipulated by RG 1.177 and depicted on Table 1 above. This conclusion is true without taking any credit for the removal of potential undesirable consequences associated with the current conservative treatment of barriers. Also, the addition of LCO 3.0.9 to LCO 3.0.1 is adequate to reflect the addition of another exception to the required barriers. Therefore, the proposed changes provide adequate protection of public health and safety and are acceptable.

Consistent with the NRC staff's approval and inherent in the implementation of TSTF-427, the licensee agreed to implement LCO 3.0.9 by operating in accordance with the following stipulations:

1.

The licensee committed to the guidance of NUMARC 93-01, Section 11 and NEI 04-08; and

2.

The licensee stated that procedures would be revised to ensure that the guidance on the risk assessment and management process described in NEI 04-08 is used whenever a barrier is considered unavailable and the requirements of LCO 3.0.9 are to be applied. This would be done in accordance with an overall CRMP to ensure that potentially risk-significant configurations resulting from maintenance and other operational activities are identified and avoided.

Consistent with TSTF-427, the licensee's application dated October 26, 2016, made regulatory commitments in Section 3.2, "Verification and Commitments," to implement LCO 3.0.9 with the above stipulations. These regulatory commitments will be controlled by the licensee's commitment change process.

4.0 STATE CONSULTATION

In accordance with the Commission's regulations, the State of Mississippi official was notified of the proposed issuance of the amendment on May 1, 2017. The State official had no comments.

5.0 ENVIRONMENTAL CONSIDERATION

The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 1 O CFR Part 20. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding published in the Federal Register on December 20, 2016 (81FR92866). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).

Pursuant to 10 CFR 51.22(b ), no environmental impact statem~ent or environmental assessment need be prepared in connection with the issuance of the amendment.

6.0 CONCLUSION

The Commission has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) there is reasonable assurance that such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

Principal Contributor: C. Tilton, NRR Date: June 7, 2017

SUBJECT:

GRAND GULF NUCLEAR STATION, UNIT 1 - ISSUANCE OF AMENDMENT TO ADOPT TECHNICAL SPECIFICATIONS TASK FORCE (TSTF)-427, REVISION 2, "ALLOWANCE FOR NON TECHNICAL SPECIFICATION BARRIER DEGRADATION ON SUPPORTED SYSTEM OPERABILITY" (CAC NO. MF8692) DATED JUNE 7, 2017 DISTRIBUTION:

PUBLIC LPL4 Reading RidsACRS_MailCTR Resource RidsNrrDorlLp14 Resource CTilton, NRR RidsNrrDssStsb Resource RidsNrrLAPBlechman Resource RidsNrrPMGrandGulf Resource RidsRgn4MailCenter Resource ADAMS A ccess1on N ML17116A032

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• b d t d 1y memo a e OFFICE NRR/DORL/LPL4/PM NRR/DORL/LPL4/LA NRR/DSS/STSB/BC*

NAME Slingam PBlechman AKlein (JWhitman for)

DATE 5/1/17 5/1/17 4/21/17 OFFICE OGC (NLO)

N RR/DORL/LPL4/BC NRR/DORL/LPL4/PM NAME MYoung RPascarelli Slingam DATE 05/30/17 06/07/17 06/07/17 OFFICIAL RECORD COPY