ML17054B701

Informs That Changes to Bases for Tech Spec 3.4.1/4.4.1 Re Reactor Bldg Leakage Rate Found Acceptable.Justification for Requested Changes Presented

ML17054B701
Person / Time
Site:	Nine Mile Point
Issue date:	05/16/1985
From:	Vassallo D Office of Nuclear Reactor Regulation
To:	Hooten B NIAGARA MOHAWK POWER CORP.
References
NUDOCS 8506170648
Download: ML17054B701 (10)

Text

Docket No. 50-220 May 16, 1985 Mr. B.

G. Hooten Executive Director, Nuclear Operations Niagara Mohawk Power Corporation 300 Erie Boulevard West

Syracuse, New York 13202

SUBJECT:

CHANGES TO THE BASES FOR SECTION 3.4. 1/4.4. 1 (REACTOR BUILDING LEAKAGE RATE)

Re:

Nine Mile Point Nuclear Station, Unit No.

1 Your November 5, 1984 letter provided a proposed amendment to the Nine Mile Point Unit 1 Technical Specifications.

The proposed amendment deleted a

page in the Technical Specifications that is no longer applicable.

That page contained the Bases for sections 3.4. 1/4.4. 1, Reactor Building Leakage Rate.

We informed you that a license amendment is not the appropriate mechanism for revising the Technical'pecification Bases and that a letter requesting this type of administrative change would be more appropriate.

Therefore, pursuant to 10 CFR 2. 107, you withdrew the request for the license amendment dated November 5, 1984 and requested that we approve your proposed Bases changes.

The following describes the requested changes and provides your justification for each:

( 1)

The first involves the deletion of statements regarding the amount of time a Reactor Building penetration could be open during normal station operation.

On December 12, 1980, the NRC issued Amendment 38 which allowed one Reactor Building penetration to be open for up to four (4) hours.

This amendment was to remain in affect until March 31, 1981 to allow for the installation of TMI-related modifications.

However, the amendment was worded such that it allowed this relief permanently.

Therefore, to avoid any potential confusion in the future, it is proposed to delete the statements allowing the four hour relief from the Technical Specifications Bases.

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Mr. B. G. Hooten (2)

The second change is also related to Amendment No.

38 and proposes to delete one page in its entirety.

As stated above, this amendment allowed for one Reactor Building penetration to be open for up to four hours.

This was to remain in effect until March 31, 1981.

This relief was stated in the Bases on page 168a.

Since this relief is no longer applicable, it is proposed to delete page 168a.

(3)

The final change involves the deletion of statements describing the preoperational testing conducted to verify the capability of the Reactor Building.

These statements were written for the original startup test program and are no longer appropriate.

In an effort to streamline the Technical Specifications and make them more efficient, it is proposed to delete these statements in their entirety.

We have reviewed your requested changes to the Bases and find them acceptable.

We have accordingly revised pages indicated in the table contained in the enclosure.

Also, a copy of these revised pages is enclosed.

Sincerely, Original signed by/

Enclosure:

As stated Domenic B. Vassallo, Chief Operating Reactors Branch ¹2 Division of Licensing cc w/enclosure:

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Mr. B. G. Hooten Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station, Unit No.

1 CC:

Troy B. Conner, Jr., Esquire Conner 5 Wetterhahn Suite 1050 1747 Pennsylvania

Avenue, N.

W.

Washington, D.

C.

20006 Frank R. Church, Supervisor Town of Scriba R.

D. ¹2

Oswego, New York 13126 Niagara Mohawk Power Corporation ATTN:

Mr. Thomas Perkins Plant Superintendent Nine Mile Point Nuclear Station Post Office Box 32

Lycoming, New York 13093 Resident Inspector U. S. Nuclear Regulatory Commission Post Office Box 126

Lycoming, New York 13093 John W. Keib, Esquire Niagara Mohawk Power Corporation 300 Erie Boulevard West

Syracuse, New York 13202 Thomas A. Murley Regional Administrator Region I Office U.

S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 19406 Mr. Jay Dunkleberger Division of Policy Analysis and Planning New York State Energy Office Agency Building 2 Empire State Plaza

Albany, New York 12223

CHANGE TO BASES SUPPORTING FACILITY OPERATING LICENSE NO.

DPR-63 DOCKET NO. 50-220 Revise the Appendix A Technical Specifications by removing and inserting the following pages:

Existing

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168 168a The revised areas are indicated by marginal lines.

Revised Paqe 168 168a

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BASES FOR 3.4.1 AND 4.4.1 LEAKAGE RATE In the answers to guestions II-3 and IV-5 of the Second Supplement and also in the Fifth Supplement,* the relationships among wind speed direction, pressure distribution outside the building, building internal pressure, and reactor building leakage are discussed.

The curve of pressure in Figure 3.4.1 represents the wind direction which results in the least building leakage.

It is assumed that when the test is performed, the wind direction is that which gives the least leakage.

If the wind direction was not from the direction which gave the least reactor building leakage, building internal pressure would not be as negative as Figure 3.4.1 indicates.

Therefore, to reduce pressure, the fan flow rate would have to be increased.

This erroneously indicates that reactor building leakage is greater than if wind direction were accounted for. If wind direction were accounted for, another pressure curve could be used which was less negative.

This would mean that less fan flow (or measured leakage) would be required to establish building pressure.

However, for simplicity it is assumed that the test is conducted during conditions leading to the least leakage while the accident is assumed to occur during conditions leading to the greatest reactor building leakage.

As discussed in the Second Supplement and Fifth Supplement, the pressure for Figure 3.4.1 is independent of the reactor building leakage rate referenced to zero mph wind speed at a negative differential pressure of 0.25 inch of water.

Regardless of the leakage rate at these design conditions, the pressure versus wind speed relationship remains unchanged for any given wind direction.

By requiring the reactor building pressure to remain within the limits presented in Figure 3.4.1 and a reactor building leakage rate of less than 2000 cfm, exfiltration would be prevented.

This would assure that the leakage from the primary containment is directed through the filter system and discharged from the 350-foot stack.

• FSAR 168

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