TSTF-07-11, Revision to Implementation Guidance for TSTF-423, Technical Specifications End States, NEDC-32988-A.

Revision to Implementation Guidance for TSTF-423, Technical Specifications End States, NEDC-32988-A.

ML070680321
Person / Time
Site:	Technical Specifications Task Force
Issue date:	03/09/2007
From:	Gambrell R, Joseph Messina, Woods B, Yates B Babcock & Wilcox, BWR Owners Group, Combustion Engineering Owners Group, PWR Owners Group, Technical Specifications Task Force
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NEDC-32988-A, TSTF-07-11, TSTF-423 TSTF-IG-05-02
Download: ML070680321 (9)

Text

TECHNICAL SPECIFICATIONS TASK FORCE TSTF A JOINT OWNERS GROUP ACTIVITY March 9, 2007 TSTF-07-11 PROJ0753 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001

SUBJECT:

Revision to the Implementation Guidance for TSTF-423, "Technical Specifications End States, NEDC-32988-A"

REFERENCE:

Federal Register, Volume 71, Number 56, March 23, 2006, "Notice of Availability of Model Application Concerning Technical Specifications for Boiling Water Reactor Plants to Risk-Inform Requirements Regarding Selected Required Action End States Using the Consolidated Line Item Improvement Process"

Dear Sir or Madam:

The referenced Federal Register notice announced the availability of TSTF-423, Revision 0, "Technical Specifications End States, NEDC-32988-A," for adoption under the Consolidated Line Item Improvement Process (CLIIP). The included model Safety Evaluation and model application required licensees to commit to following the associated implementation guidance document, TSTF-IG-05-02, "Implementation Guidance for TSTF-423, Revision 0, 'Technical Specifications End States, NEDC-32988-A'."

At the January 18, 2007 meeting between the NRC and the Nuclear Energy Institute Risk Informed Technical Specifications Task Force (NEI RITSTF), the NRC stated that there was a concern within the NRC staff that the implementation guidance provided an allowance regarding the operability of primary and secondary containment that was not contained in the NRC's Safety Evaluation for TSTF-423.

The TSTF reviewed the NRC's concern and we have revised the implementation guidance to remove the allowance in order to be consistent with the NRC's Safety Evaluation for TSTF-423.

The revised implementation guidance document, TSTF-IG-05-02, Revision 1, is attached. The specific changes are described in the "Revision Description" section.

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

TSTF 07-11 March 9, 2007 Page 2 The NRC's review of TSTF-423 and Revision 0 of TSTF-IG-05-02 was granted a fee waiver in the NRC letter to A. R. Pietrangelo dated January 10, 2003. We request that the NRC review of the revision to the implementation guidance continue to be granted a fee waiver pursuant to the provisions of 10 CFR 170.11. Specifically, the request is to support NRC generic regulatory improvements (risk management technical specifications), in accordance with 10 CFR 170.11(a)(1)(iii).

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

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

Brian Woods (PWROG/CE) Reene' Gambrell (PWROG/B&W)

Enclosure cc: Tim Kobetz, Technical Specifications Branch, NRC Ross Telson, Technical Specifications Branch, NRC

TECHNICAL SPECIFICATIONS TASK FORCE TSTF A JOINT OWNERS GROUP ACTIVITY TSTF-IG-05-02 IMPLEMENTATION GUIDANCE FOR TSTF-423, REVISION 0, "TECHNICAL SPECIFICATIONS END STATES, NEDC-32988-A" REVISION 1 MARCH 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-05-02, Rev. 1 March, 2007 ACKNOWLEDGMENTS This document, Implementation Guidance for TSTF-423, Revision 0, "Technical Specifications End States, NEDC-32988-A," was developed by the Boiling Water Reactor Owners Group (BWROG), the Nuclear Energy Institute (NEI) Risk Informed Technical Specification Task Force (RITSTF), and the Technical Specifications Task Force (TSTF).

The TSTF wishes to acknowledge the efforts of John D. (Don) McCamy of the Tennessee Valley Authority, George S. (Steve) Cashell of DTE Energy, the NEI RITSTF, the BWROG, and U.S. Nuclear Regulatory Commission reviewers, in creating this document.

REVISION DESCRIPTION Revision 1 modifies Section 1, numbered items 4 and 5,which state:

4. If Primary Containment is not operable, Secondary Containment and Standby Gas Treatment must be verified operable in order to remain in Mode 3, unless a plant specific risk evaluation is prepared.

5. If Secondary Containment is not operable, Primary Containment must be verified operable in order to remain in Mode 3, unless a plant specific risk evaluation is prepared.

In both items, the phrase, ", unless a plant specific risk evaluation is prepared" is deleted. This revision was requested by the NRC. This option was not discussed in the NRC's Safety Evaluation for TSTF-423.

TSTF-IG-05-02, Rev. 1 March, 2007 TABLE OF CONTENTS ACKNOWLEDGMENTS AND REVISION DESCRIPTION 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 BWROG Topical Report................................................ 3 2.3 General Guidance ............................................................................................ 3 3 DOCUMENTATION ............................................................................................... 4 4 REFERENCES........................................................................................................ 4 i

TSTF-IG-05-02, Rev. 1 March, 2007 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 NEDC-32988-A, "Technical Justification to Support Risk-Informed Modification to Selected Required Action End States for BWR Plants" (Reference 1), and the associated NRC Safety Evaluation (Reference 2). The report concluded, and the NRC concurred, that for short duration operation, Mode 3 (hot shutdown) is a risk neutral or risk beneficial end state compared to Mode 4 (cold shutdown). A "short duration" is envisioned to be the duration that boiling water reactors (BWRs) are most physically and practicably able to remain in the hot shutdown condition (i.e., from a few days to approximately one week). The risk benefit from this change is largely due to the availability of increased heat removal resources in Mode 3.

The analyses described in Reference 1 were used to create TSTF-423, "Technical Specifications End States, NEDC-32988-A" (Reference 3). TSTF-423 modifies NUREGs 1433 and 1434, the Improved Standard Technical Specifications (ISTS) for BWR/4 and BWR/6 plants. TSTF-423 modifies the end state for a limited set of Technical Specifications (TS) which are applicable in Modes 1, 2, and 3 to allow operation in Mode 3 with equipment governed by the TS 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-423 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 1

TSTF-IG-05-02, Rev. 1 March, 2007 assessments. Assessments may credit existing analyses and insights drawn from Reference 1 as they apply to the current plant operating condition.

3. 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 3 to a Mode in which the risk is reduced.

4. If Primary Containment is not operable, Secondary Containment and Standby Gas Treatment must be verified operable in order to remain in Mode 3.

5. If Secondary Containment is not operable, Primary Containment must be verified operable in order to remain in Mode 3.

6. Any entry into Mode 3 using this TS allowance must be limited to no more than seven days.

7. Although not mandatory, plants should attempt to reduce pressure to less than 500 psig within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after entering Mode 3. Risk should be assessed for those periods of time that the plant is above 500 psig after 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> in Mode 3.

8. Plants submitting a license amendment to adopt the preferred end states described in Reference 1 and TSTF-423 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-423.

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, 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 3 is equal to or less than that in going to Mode 4, and that extended operation in Mode 3 is thus acceptable.

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TSTF-IG-05-02, Rev. 1 March, 2007 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 3, the use of a key safety function defense-in-depth approach, as discussed in NUMARC 91-06, "Shutdown Risk 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 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 3 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 BWROG Topical Report When implementing the Mode 3 allowance, the BWROG Topical Report (Reference

1) and the NRC safety evaluation (Reference 2) contain valuable information with respect to remaining in Mode 3. 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 3 as allowed by TSTF-423:

1. When performing risk assessments and risk management of maintenance performed while in the Mode 3 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 3 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.

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TSTF-IG-05-02, Rev. 1 March, 2007 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, consistency of application, and clear communication of risk management actions to appropriate plant personnel.

4 REFERENCES

1. NEDC-32988-A, Revision 2, "Technical Justification to Support Risk-Informed Modification to Selected Required Action End States for BWR Plants," dated December 2002.

2. NRC Safety Evaluation for Topical Report NEDC-32988, Revision 2, dated September 27, 2002.

3. TSTF-423, Revision 0, "Technical Specifications End States, NEDC-32988-A."

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, "Shutdown Risk Management," December 1991.

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