ML20117K305

Application for Amend to License NPF-86,implementing Performance Based Containment Leak Rate Testing Program at Seabrook Station by Changing Tss.Request Submitted IAW 10CFR50,App J,Option B & Reg Guide 1.163 Requirements

ML20117K305
Person / Time
Site:	Seabrook
Issue date:	06/04/1996
From:	Feigenbaum T NORTH ATLANTIC ENERGY SERVICE CORP. (NAESCO)
To:
Shared Package
ML20117K296	List: ML20117K293 ML20117K305 ML20117K311
References
RTR-REGGD-01.163, RTR-REGGD-1.163 TAC-M95312, NUDOCS 9606110085
Download: ML20117K305 (8)

Text

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North l Atlantic I 1

Facility Operating License NPF-86 Docket No. 50-443 i License Amendment Request No. 96-05  !

IMPLEMENTATION OF 10CFR50 APPENDIX J, OPTION B '

CONTAINMENT LEAKAGE RATE TESTING (TACM95312)

SEABROOK STA TION i

s This License Amendment Request is submitted by North Atlantic Energy Service Corporation l pursuant to 10CFR50.90. The following information is enclosed in support of this License Amendment Request:

Section 1 -

Introduction and Safety Assessment for the Proposed Changes Section 11 -

Markup of Proposed Changes Section 111 -

Retype of Proposed ChangesSection IV -

Determination of Significant Hazards for Proposed ChangesSection V - Proposed Schedule for License Amendment issuance and EffectivenessSection VI - Environmentallmpact Assessment Sworn and Subscribed to before 6# day meof U/ thiq,MfL- ,1996 N

M gj b Mp/@n Ted C. Folgenbaum

~

Not.ny5ublic

( Executive Vice P ident and Chief Nuclear Officer 9606110085 960604 PDR ADOCK 05000443 p PDR

I. Introduction and Safety Assessment for the Proposed Changes A. Introduction ,

Containment leakage rate testing includes the performance of an Integrated Leak Rate Test (ILRT), or Type A test, and Local Leakage Rate Tests (LLRTs), or Type B and Type C tests. Type A tests assess the overall leakage rate of the primary reactor containment while Type B tests detect leakage paths and assess leakage for certain primary containment penetrations. Type C tests assess containment isolation valve leakage rates. The requirements for the aforementioned types of leakage rate testing are delineated in 10CFR50, Appendix J (hereafter, Appendix J).

The Appendix J testing requirements ensure that leakage through the primary containment and systems penetrating primary containment does not exceed allowable leakage rate values as specified in the Technical Specifications ot associated Bases. These requirements ensure that an adequate primary containment boundary is maintained during and after an accident by minimizing potential leakage paths to the environment and that the primary containment function as assumed in the safety analysis will be maintained.

On February 4, 1992, the NRC published in the Federal Register the agency's planned actions and initiatives to eliminate requirements that are marginal to safety and yet impese significant regulatory burdens on licensees. The NRC concluded that decreasing the prescriptiveness of some regulations may improve their effectiveness by providing flexibility to licensees to implement cost effective safety measures. It was determined that the detailed and prescriptive technical requirements contained in some regulations could be improved and replaced with performance based requirements and supporting regulatory guides.

In accordance with the above conclusions, the NRC indicated that modifications to Appendix J could be considered. The performance-based containment leakage testing option, Option B of 10CFR50, Appendix J, became effective on October 26, 1995. This option allows the use of a reduced testing frequency for primary containment systems and components, based on performance history. The implementation of this option requires the development of a program based on Regulatory Guide 1.163, and modification of the technical specifications to reference this program.

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Description of Proposed Changes North Atlantic proposes to modify the Seabrook Station Technical Specifications to implement Option B to 10CFR50 Appendix J in accordance with Regulatory Guide 1.163. The Regulatory Guide endorses

, the performance based methods contained within NEI 94-01, Revision 0, l

• Industry Guideline for Implementing Performance Based Option of j 10CFR50 Appendix J", dated July 26, 1995. As required by Appendix J,

Regulatory Guide 1.163 is included by general reference in the l proposed changes to the Technical Specifications. j The Technical Specifications for Seabrook Station are proposed to be j l modified as follows

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1. Definitions: Definition 1.7; Containment Integrity (Item d.)

is revised to reflect that leakage rates are in accordance j with the Containment Leakage Rate Testing Program.

2. Limiting Condition for Operation and Surveillance Requirements:

l a. Containment Integrity: Surveillance Requirement 4.6.1.1.c is deleted because the specific guidance is

! contained in the Containment Leakage Rate Testing Program.

b. Containment Leakage: Limiting Condition for Operation 3.6.1.2.a-c and Surveillance Requirements 4.6.1.2.a-h are revised to replace specific guidance with a reference to the Containment Leakage Rate Testing

, Program.

c. Containment Leakage: The Action for Limiting Condition for Operation 3.6.1.2 is revised to include the I equivalent Action as required for Limiting Condition for Operation 3.6.1.1 when the overall integrated containment leak rate exceeds 1.0 L.,

d. Containment Air Locks: Limiting Condition for Operation 3.6.1.3.a-b is deleted and Surveillance Requirements 4.6.1.3.a-b are revised to replace specific guidance with a reference to the Containment Leakage Rate Testing Program. The footnote dddressing

the exemption to Appendix J regarding testing the air j locks prior to establishing containment integrity will l be maintained in the Containment Leakage Rate Testing l

Program.

( e. Containment Vessel Structural' Integrity: Surveillance Requirement 4.6.1.6 is revised to replace specific i

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guidance with a reference to the Containment Leakage Rate Testing Program.

f. Containment Ventilation System: Limiting Condition for Operation 3.6.1.7, Action b. is revised to replace specific guidance with a reference to the Containment Leakage Rate Testing Program. Surveillance Requirement 4.6.1.7.1 is revised to replace specific guidance with l a reference to the Containment Leakage Rate Testing l Program.

g. Containment Enclosure Building: Limiting Condition for Operation 3.6.5.3 and Surveillance Requirement 4.6.5.3 are revised to include a reference to the requirements in the Containment Leakage Rate Testing Program.

3. Bases: Sections 3/4.6.1.2 (Containment Leakage), 3/4.6.1.7 (Containment Ventilation System) and 3/4.6.5.3 (Containment Enclosure Building Structural Integrity) are revised to l reflect the above changes including a reference to the Containment Leakage Rate Testing Program. In addition, a statement has been added to Section 3/4.6.1.2 to clarify the operability of containment regarding allowable leakage rates.

4. Administrative Controls: Section 6.15 is added to establish a Containment Leakage Rate Testing Program, as specified in Regulatory Guide 1.163, dated September 1995.

Summary of Changes to Seabrook Station Containment Leakage Testing l The proposed changes to the Technical Specifications will result in ,

the following changes to containment leakage testing at Seabrook j Station: 1 The current Type A test schedule la three tests in a 10 year period. l Based on demonstrating compliance with the performance criteria of Option B to Appendix J and references therein, the Type A test schedule could be extended to one test in a 10 year period.

If a Type A test is failed and the failure is not due to a Type B or C component, acceptable performance shall be reestablished by performing a Type A test within 48 months of the unsuccessful Type A test.

Following a successful Type A test, the surveillance frequency may be returned to once per 10 years. If a Type A test failure is caused by j

failure (s) of a Type B or C component, the corrective action for Type B and C failures would apply as stated below. In addition, the primary containment leakage rate acceptance criteria for operability remains at an overall leakage limit of 5; 1.0L..

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General inspections of the accessible interior and exterior surfaces of the containment structures will be conducted prior to initiating a Type A test, and during two other refueling outages before the next Type A test if the interval for the Type A test has been extended to 10 years, in order to allow for early detection of evidence of structural deterioration.

Extensions in Type B and C test intervals are allowed based upon completion of two consecutive successful periodic as-found tests.

Type B tests (with the exception of airlocks) may be extended to a maximum interval of 10 years. Type C tests (with the exceptions of containment purge and vent valves) may be extended to a maximum interval of 5 years. If a Type B or C test is not successful, the test frequency will be set at the initial test intervals.

Performance factors that will be considered prior to extending intervals are as follows:

a) Past component Performance -

Leakage rate testing intervals should not be extended until plant-specific component performance of two successful consecutive As-found tests are performed.

b) Service - Environment and use of components, c) Design - Valve type and penetration design.

d) Safety Impact -

Potential impact of penetration failure in limiting releases from the containment under accident conditions.

e) cause Determination - Common-mode failure mechanisms.

Test intervals will be established by reviewing Type B and C test data and determining if the Type B or C tests for each component had passed l or failed. The test interval assignments and all supporting l evaluations will be documented. If it is determined that a component l will remain on a two-year interval regardlesc of its historical l performance, interval establishment is not required. The allowable leakage rates are assigned to each Type B and C component. The allowable leakage rate assigned to each component is the administrative leakage rate limit and is specified to be indicative of the potential onset of component degradation. The leakage rate acceptance criteria are established in a conservative manner. In ;

setting these limits, credit is not taken for the effects of multiple penetration barriers in further reducing overall leakage through the penetration. Therefore, the acceptance criteria for the Type B and C tests remain at very low values.

Airlock testing has been increased to an interval of once per 30 months. When containment is required, airlock door seals will be tested within 7 days after each containment access. For periods of multiple containment entries where the airlock doors are routinely used for access more frequently than once every 7 days, door seals may be tested once per 30 days.

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O The North Atlantic allowable leakage rates or administrative limits for each component will be specified such that they are an indicator of potential valve or penetration degradation. A failure of the allowable leakage rate or administrative limit is not a failure of the Technical Specification requirement.

No change in the method of testing is being proposed. The tests will continue to be done at P., The test pressure for primary containment isolation valves will continue to be applied in the same direction as would be required for the valve to perform its safety function (unless a different direction can be shown to be equivalent or more conservative. Other programs are in place to ensure that proper maintenance and repairs are performed during the service life of the primary containment and systems and components penetrating the primary containment.

i B. Safety Assessment of the Proposed Changes The changes proposed by License Amendment Request 96-05 revise the l existing specific guidance in the Seabrook Station Technical j Specifications with a reference to a Containment Leakage Rate Testing l Program. The Containment Leakage Rate Testing Program will be l established in accordance with the recommendations of Regulatory Guide '

1.163, " Performance Based Containment Leak Test Program." This program will provide the acceptance criteria and testing schedule for containment penetrations in accordance with 10CFR50, Appendix J, Option B. ,

l The proposed implementation of 10CFR50, Appendix J, Option B has been determined to have a minimal impact on public health and safety, 1 Option B allows for reduced testing of those containment penetrations which have acceptable performance histories.

The k Staff has reviewed the potential impac'ts on safety associated with tLe implementation of 10CFR50, Appendix J, Option B and documented the impact in NUREG-1493, " Performance-Based Containment Leakage-Test Program." The document summarizes the impact of reducing the frequency of Type A tests from the current three tests in ten years to one test in ten years as an imperceptible increase in risk.

The Type B and C testing frequency changes are expected to contribute less than 0.1 percent (0.001) of the overall accident risk. *The overall impact of the combined rule changes were very small. EPRI Research Project Report TR-104285, " Risk Impact Assessment of Revised Containment Leak Rate Testing Intervals," also concluded that a relaxation of the test intervals for Type B and C penetrations results in a negligible increase in total plant risk. The implementation of Option B will allow the test intervals to be extended without challenging the radiological release limits from the site since all of the penetrations are periodically tested with leakage rates well below the specified limits.

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The testing history of containment penetrations at Seabrook Station has shown that the implementation of Option B will provide an appropriate level of assurance that the containment will perform the intended function and the radiological release limits will be maintained well below the limits set in 10CFR100.

The implementation of Option B will also reduce the exposure to personnel during performance of the required testing in accordance with the Containment Leakage Rate Testing Program. NUREG-1493 concluded that for Type B and C testing, although reducing the testing frequency led to minor increases in potential off-site dose

. consequences, the actual decrease in on-site (worker) doses exceeded (by at least an order of magnitude) the potential off-site dose increases.

In summary, the proposed performance based containment leakage rate testing program will have a minimal impact on public health and safety for the following reasons;

• The overall performance goal of ensuring containment isolation

with a high degree of reliability can be demonstrated based upon continued excellent performance of the containment penetrations.

l Qualitative performance factors are considered in establishing performance criteria. These factors consider past - performance, component design, component service, safety impact and cause determination. =

• Quantitative acceptance criteria for testing will continue to be i established in a conservative manner.

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• Quantitative criteria for testing intervals are based on

demonstrated component performance and the achievement of the l overall performance goal.

• The performance based testing program will continue to provide l

assurance that the accident analysis assumptions remain bounding.

l Conclusion Based on the above, the implementation of 10CFR50, Appendix J, Option B in accordance with Regulatory Guide 1.163 will provide adequate assurance that the containment will perform the design function, and have minimal impact on public health and safety or radiological releases.

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II. Markup of Proposed Changgg See attached markup of proposed changes to Technical Specifications.

The attached markup reflects the currently issued . revision of Technical Specifications. Pending Technical Specifications or Technical Specification changes issued subsequent to this submittal are not reflected in the enclosed markup.

l The page numbers of the affected pages are listed below.

, 1-2 Definitions I 3/4 6-1 Containment Integrity 3/4 6-2 Containment Leakage 3/4 6-3 Containment Leakage 3/4 6-4 Containment Leakage 3/4 6-7 Containment Air Locks 3/4 6-8 Containment Air Locks 3/4 6-11 Containment. Vessel Structural Integrity l 3/4 6-12 Containment Ventilation System 3/4 6-13 Containment Ventilation System 3/4 6-25 Containment Enclosure Building Structural Integrity Item 6.15 Administrative Controls B 3/4 6-1 Containment Systems B 3/4,6-2 Containment Systems B 3/4 6-4 Containment Systems l

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