TSTF-07-15, TSTF-IG-07-01, Implementation Guidance TSTF-431, Revision 1, Change in Technical Specifications End States (BAW-2441).

TSTF-IG-07-01, Implementation Guidance TSTF-431, Revision 1, Change in Technical Specifications End States (BAW-2441).

ML071000281
Person / Time
Site:	Technical Specifications Task Force
Issue date:	04/10/2007
From:	Gambrell R, Joseph Messina, Millar D, Yates B BWR Owners Group, PWR Owners Group, Technical Specifications Task Force
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
BAW-2441, BAW-2441-A, Rev. 2, TSTF-07-15, TSTF-431, Rev. 1, TSTF-IG-07-01
Download: ML071000281 (8)

Text

TECHNICAL SPECIFICATIONS TASK FORCE TSTF A JOINT OWNERS GROUP ACTIVITY April 10, 2007 TSTF-07-15 PROJ0753 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001

SUBJECT:

TSTF-IG-07-01, "Implementation GuidanceTSTF-431, Revision 1, Change in Technical Specifications End States (BAW-2441)"

Dear Sir or Madam:

Enclosed for NRC reference is TSTF-IG-07-01, "Implementation Guidance for TSTF-431, Revision 1, 'Change in Technical Specifications End States (BAW-2441)'." This document provides implementation guidance for TSTF Traveler TSTF-431 and reflects the considerations in the NRC's approval of the related Topical Report, BAW-2441-A, Revision 2, "Risk Informed Justification for LCO End-State Changes."

Should you have any questions, please do not hesitate to contact us.

Bert Yates (PWROG/W) John Messina (BWROG)

Dana Millar (PWROG/CE) Reene' Gambrell (PWROG/B&W)

Enclosure cc: Tim Kobetz, Technical Specifications Branch, NRC Ross Telson, Technical Specifications Branch, NRC 11921 Rockville Pike, Suite 100, Rockville, MD 20852 Phone: 301-984-4400, Fax: 301-984-7600 Email: tstf@excelservices.com Administered by EXCEL Services Corporation

TECHNICAL SPECIFICATIONS TASK FORCE TSTF A JOINT OWNERS GROUP ACTIVITY TSTF-IG-07-01 IMPLEMENTATION GUIDANCE FOR TSTF-431, REVISION 1, "CHANGE IN TECHNICAL SPECIFICATIONS END STATES (BAW-2441)"

APRIL 2007 11921 Rockville Pike, Suite 100, Rockville, MD 20852 Phone: 301-984-4400, Fax: 301-984-7600 Email: tstf@excelservices.com Administration by EXCEL Services Corporation

TSTF-IG-07-01, Rev. 1 April, 2007 ACKNOWLEDGMENTS This document, Implementation Guidance for TSTF-431, Revision 1, "Change in Technical Specifications End States (BAW-2441)," was developed by the Technical Specifications Task Force (TSTF), AREVA NP, the Pressurized Water Reactors Owners Group (PWROG), and the Nuclear Energy Institute (NEI) Risk Informed Technical Specification Task Force (RITSTF).

TSTF-IG-07-01, Rev. 1 April, 2007 TABLE OF CONTENTS ACKNOWLEDGMENTS TABLE OF CONTENTS................................................................................................. i 1 Impact on the Maintenance Rule (A)(4) Program for Assessment and Management of Risk ............................................................................................... 1 2 RISK ASSESSMENT AND MANAGEMENT CONSIDERATIONS .................... 2 2.1 Methods of Assessment ................................................................................... 2 2.2 Considerations from Topical Report ............................................................... 3 2.3 General Guidance ............................................................................................ 3 3 DOCUMENTATION ............................................................................................... 3 4 REFERENCES........................................................................................................ 4 i

1 IMPACT ON THE MAINTENANCE RULE (A)(4) PROGRAM FOR ASSESSMENT AND MANAGEMENT OF RISK The technical basis for the preferred end states initiative is contained in BAW-2441, Revision 2, "Risk Informed Justification for LCO End-State Changes," (Reference 1) and the associated NRC Safety Evaluation (Reference 2). The report concluded, and the NRC concurred, that for short duration operation, Mode 4 (hot shutdown) is a risk neutral or risk beneficial end state compared to Mode 5 (cold shutdown). The risk benefit from this change is largely due to the availability of increased heat removal resources in Mode 4.

The analyses described in Reference 1 were used to create TSTF-431, "Change in Technical Specifications End States (BAW-2441)" (Reference 3). TSTF-431 modifies NUREG-1430, the Improved Standard Technical Specifications (ISTS) for Babcock and Wilcox plants. TSTF-431 modifies the end state for a limited set of Technical Specifications (TS) which are applicable in Modes 1, 2, 3, and 4 to allow operation in Mode 4 when equipment governed by the TS is inoperable.

Implementation of the preferred end states initiative requires some modification of the current program for implementing 10 CFR 50.65(a)(4), the Maintenance Rule.

These modifications are intended to preclude preventive maintenance and operational activities being performed on equipment combinations that could lead to reduced defense-in-depth and potentially high risk configurations, and to identify actions for expeditiously exiting a risk-significant configuration should it occur.

These modifications are discussed below:

1. Plants implementing TSTF-431 must commit to the guidance contained in NUMARC 93-01, "Industry Guideline for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants" (Reference 4), Section 11, for Maintenance Rule risk assessments. NRC Regulatory Guide 1.182, "Assessing and Managing Risk Before Maintenance Activities at Nuclear Power Plants" (Reference 5), states that the NUMARC guidance is one acceptable approach for implementing 10 CFR 50.65(a)(4). The guidance provides flexibility with respect to risk assessment and management approaches and allows for a combination of qualitative and quantitative evaluations, as well as use of bounding assessments.

2. Use of the preferred end state to perform maintenance will require a risk assessment consistent with 10 CFR 50.65(a)(4). Qualitative assessments that recognize the contemporaneous configuration and refer to insights identified in the Topical Report (Reference 1) are acceptable, as are bounding quantitative assessments. Assessments may credit existing analyses and insights drawn from Reference 1 as they apply to the current plant operating condition.

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3. Use of the preferred end state is for a short interval, with the primary intent being to repair a nonfunctional component and return the plant to power as soon as practical.

4. Should contemporaneous risk assessments result in the identification of a high risk configuration, risk management actions should be taken. These actions may include exiting Mode 4 to a Mode in which the risk is reduced.

5. Plants submitting a license amendment to adopt the preferred end states described in Reference 1 and TSTF-431 must commit to implementing the guidance in this document.

2 RISK ASSESSMENT AND MANAGEMENT CONSIDERATIONS This section describes considerations for risk assessment and management relative to implementation of TSTF-431.

2.1 Methods of Assessment NUMARC 93-01 provides separate guidance for risk assessment during power operation (Section 11.3.4), and during shutdown conditions (Section 11.3.6). Thus, Section 11.3.6, Assessment Methods for Shutdown Conditions, of NUMARC 93-01 contains the appropriate guidance for performing risk assessments for maintenance while utilizing the preferred end states initiative. The NUMARC 93-01 guidance is based on maintaining defense-in-depth for key safety functions necessary for safe shutdown. Reference 1 uses both qualitative and quantitative evaluations of representative plants to demonstrate that the risk impact from remaining in Mode 4 is equal to or less than that in going to Mode 5, and that the proposed operation in Mode 4 is thus acceptable.

It is expected that consideration of the risk impact of maintenance performed while in the preferred end state will generally be performed qualitatively, or through a combination of qualitative and quantitative methods. For those plants capable of quantification, the risk impact of maintenance while in the preferred end state may be quantified, compared to risk management thresholds provided in section 11.3.7.2 of NUMARC 93-01, and appropriate risk management actions implemented.

In performing the risk assessments for maintenance while in Mode 4, the use of a key safety function defense-in-depth approach, as discussed in NUMARC 91-06, "Guidelines for Industry Actions to Assess Shutdown Management" (Reference 6),

and Section 11 of NUMARC 93-01, is considered an acceptable approach for satisfying the requirements regarding risk assessment and management. In 2

performing this assessment, it should be ensured that adequate defense-in-depth for key safety functions will be preserved when performing maintenance while utilizing the preferred end state. Application of the key safety function approach to Mode 4 may require additional considerations relative to the reactor coolant being at higher temperature and being above atmospheric pressure. Quantitative lower Mode risk assessments may also be used provided appropriate tools and models are available.

2.2 Considerations from Topical Report When implementing the Mode 4 allowance, the Topical Report (Reference 1) and the NRC safety evaluation (Reference 2) contain valuable information with respect to remaining in Mode 4. This information should be incorporated in plant operating procedures and practices as applicable.

2.3 General Guidance The following general guidance is provided for performing risk assessments of maintenance performed while remaining in Mode 4 as allowed by TSTF-431:

1. When performing risk assessments and risk management of maintenance performed while in the Mode 4 end state, the licensees must consider all maintenance being performed, regardless of whether the maintenance is related to restoring the inoperable equipment which lead to the use of the Mode 4 end state.

2. If plant conditions change during performance of maintenance, 10 CFR 50.65(a)(4) requires the new condition to be evaluated, and if necessary, risk management actions to be taken. The actions may include stopping the maintenance activity, completing the activity, transitioning the plant to a lower Mode, or other risk management actions. These actions are implemented in plant procedures.

3 DOCUMENTATION Programs for risk assessment and management are required to be proceduralized in accordance with NUMARC 93-01; however, documentation of each individual use of the risk assessment and risk management actions for maintenance performed while utilizing the preferred end state is not required by NRC. Although not required, it may be prudent to document these activities for internal reasons, including communication between plant organizations, turnover of operating crews, 3

consistency of application, and clear communication of risk management actions to appropriate plant personnel.

4 REFERENCES

1. BAW-2441-A, Revision 2, "Risk Informed Justification for LCO End-State Changes," September 2006.

2. Letter from H. K. Neih (NRC) to G. Bishoff (PWROG), "Final Safety Evaluation for BAW-2441, Revision 2, 'Risk Informed Justification for LCO End-State Changes'," dated August 25, 2006.

3. TSTF-431, Revision 1, "Change in Technical Specifications End States (BAW-2441)."

4. NUMARC 93-01, "Industry Guideline For Monitoring The Effectiveness Of Maintenance At Nuclear Power Plants," Revision 3, July 2000.

5. NUREG 1.182, "Assessing and Managing Risk Before Maintenance Activities at Nuclear Power Plants," May 2000.

6. NUMARC 91-06, "Guidelines for Industry Actions to Assess Shutdown Management," December 1991.

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