ML18152A772

Application for Amends to Licenses DPR-32 & DPR-37,granting Exemption from 10CFR50,App J,Paragraph III.A.3 Re Performance of Type a Tests Per ANSI N45.4-1972, Leakage Rate Testing of Containment Structures For.... Fee Paid

ML18152A772
Person / Time
Site:	Surry
Issue date:	03/01/1988
From:	Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML18152A773	List: ML18152A772 ML18152A774
References
88-005, 88-5, NUDOCS 8803080179
Download: ML18152A772 (6)

Text

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• e e 10 CFR 50 VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 W. L. STEWART VICE PRESIDENT March 1, 1988 NUCLEAR OPERATIONS U.S. Nuclear Regulatory Commission Serial No ..88-005 Attn: Document Control Desk NO/ETS:vlh Washington, D. C. 20555 Docket Nos. 50-280 50-281 License Nos. DPR-32 DPR-37 Gentlemen:

VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS I AND 2 10 CFR 50, APPENDIX J EXEMPTION REQUEST Pursuant to 10 CFR 50.12, Virginia Electric and Power Company requests an exemption from 10 CFR 50, Appendix J, Paragraph III.A.3, which requires that Type A (Containment Integrated Leak Rate) tests be performed in accordance with ANSI N45.4-1972, "Leakage Rate Testing of Containment Structures for Nuclear Reactors." Since the issuance of ANSI N45.4-1972, a more accurate method of determining containment leakage rates, the mass point method, was developed as described in ANSI 56.8-1981, "Containment System Leakage Testing Requirements." Therefore, Virginia Electric and Powet Company is requesting exemption to a11 ow use of the mass point method for ca lcul at i ng containment leakage rates.

Based on the justification provided in Attachment 1, we conclude that the exemption from the requirements of Appendix J, Paragraph III.A.3 is justified pursuant to 10 CFR 50.12(a)(l) and 10 CFR 50.12(a)(2)(ii) in that it is authorized by law; will not present undue risk to public health and safety, and is consistent with the common defense and security. Additionally, special circumstances are present in this case in that application of the regulation is not necessary to achieve the underlying purpose of the rule. The mass point method will satisfy the accuracy requirements of 10 CFR 50, Appendix J, Paragraph III.A.3 for Type A tests.

In addition, a change to our Technical Specifications is r~quired in order to maintain consistency between Appendix J, our exemption request and the Technical Specifications. The proposed changes to Technical Specification are contained in Attachment 2 and the discussion of the proposed changes is contained in Attachment 3.

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e The exemption request and proposed Technical Specification change has been reviewed and approved by the Station Nuclear Safety and Operating Committee and the Safety Evaluation and Control Staff. It has been determined that the exemption request and Technical Specification change do not pose an unreviewed safety question as defined by 10 CFR 50.59 nor does it pose a significant safety hazards consideration as defined by 10 CFR 50.92.

In accordance with 10 CFR 170 an application fee of $150 is enclosed. If you have any questions or need additional information to process this request please contact us.

Very truly yours, DL~~:&

W. L. Stewart Attachments

1) Justification of Exemption

2) Proposed Technical Specification Change

3) Discussion of Proposed Changes

4) Application Fee cc: U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, N. W.

Suite 2900 Atlanta, Georgia 30323 Mr. W. E. Holland NRC Senior Resident Inspector Surry Power Station Mr. Charles Price Department of Health 109 Governor Street

• Richmond, Virginia 23219 Mr. Chandu P. Patel NRC Surry Project Manager Project Directorate 11-2 Division of Reactor Projects - 1/11

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• COMMONWEALTH OF VIRGINIA)

)

CITY OF RICHMOND )

The foregoing document was acknowledged before me, in and for the City and Commonwealth aforesaid, today by W. L. Stewart who is Vice President - Nuclear Operations, of Virginia Electric and Power Company. He is duly authorized to execute and file the aforegoing document in behalf of that Company, and the statements in the document are true to the best of his knowledge and belief.

Acknowledged before me this / 9::_T day of cll1,{llLC/tJ , 19Q.S_.

My Commission expires: ~ I r ~ Z5, 19'7l>,

&h* X.i!ML Notary Public (SEAL)

• -,. / - .:::-

e ATIACHMENT 1 JUSTIFICATION OF EXEMPTION

BACKGROUND e e In 1973, 10 CFR 50 Appendix J was issued to establish requirements for Primary Reactor Containment Leakage Testing. Appendix J incorporated by reference ANSI N45.4-1972, "Leakage Rate Testing of Containment Structures for Nuclear Reactors." The Standard requires that containment leakage calculations be performed using either the point-to-point method or the total time method.

The total time method was used most by the nuclear industry until about 1976.

As noted in ANSI N45.4, the point-to-point method is suited to uninsulated containments where atmospheric stability is affected by outside diurnal change, while the total time method is appropriate for insulated containments that are relatively unaffected by diurnal changes. In 1976, an article (reference: "Containment Leak Rate Testing: Why the Mass-Point Analysis Method is Preferred," Power Engineering, February 1976) was written which compared the results of test analyses that were performed using point-to-point, total time, and mass-point techniques. A revision to the Standard (ref.: ANSI/ANS 56.8-1981, "Containment System Leakage Testing")

. specifies the use of mass-point. The draft revision to Appendix J incorporates the new standard ANSI/ANS 56.8-1981.

JUSTIFICATION Virginia Electric and Power Company believes that this exemption should be granted pursuant to 10 CFR 50.12(a)(2)(ii); i.e., application of the regulation in the particular circumstances is not necessary to achieve the underlying purpose of the rule, ~hich is to provide an accurate and conservative test of containment integrity.

Mass-point is a newer and more accurate method of ca lcul at i ng containment leakage. The total time method cal cul ates a series of leakage rates based upon air mass differences between an initial data point and each individu~l data point thereafter. The adequacy of the method is extremely sensitive to the accuracy of that initial data point. If, due to any reason (su*ch as instrument error, lack of temperature equilibrium, ingassing or outgassing) the initial data point is not accurate, the results of the test will be affected. Even if the data point is accurate, during the early stages of the test the leakage varies with time; as a result the initial value and therefore the calculated leak rate become time dependent. In the mass-point method, the mass of air in containment is calculated and plotted as a function of time.

The slope of the linear least squares fit to the data is the leakage.

Using the total time method, the calculation of leakage rates as a function of time required creates the situation where increasing the amount of data

. ava i 1ab 1e causes the results to become more erratic and the 95% Confidence Interval to become wider. Using the total time method, the 95% confidence interval may range from one-half to twice the measured leak rate. In the case of mass-point method, the 95% confidence interval is between 5% and 20% of the measured leak rate.

• Additionally, Virginia Electric and Power Company believes that this exemption request will not result in undue risk to the health or safety of the public, in that; the proposed exemptions do not change, modify, or restrict existing plant safety limits, safety settings, systems or operation; or impact the design basis of the containment or modify its response during a DBA ..

e ATTACHMENT 2 PROPOSED TECHNICAL SPECIFICATION CHANGE