ML19320D195

Part 21 Rept Re Existence of Nonconservative Assumption in Cold Shutdown Design Basis Boron Dilution Accident Analysis in Fsar.Caused by Use of Incorrect Sys Vol.Review Will Be Performed to Identify & Analyze Addl Accidents

ML19320D195
Person / Time
Site:	Surry, North Anna
Issue date:	07/02/1980
From:	Sylvia B VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
References
REF-PT21-80-242-000 582, NUDOCS 8007210092
Download: ML19320D195 (4)

Text

ATTAGED IS A PART 21 REPORT FROM IE PAIL UNIT - ROOM 359 E/W

,.PART21IDEfEIFICATIONNO.. 3o - 2 M2-o o a C0FPANY NATE pid

'DATE OF LETTER. 7/st/f d DOCKET NO. So-3 A r j ro - 3 3 r DATE DISTRIBUTED V //o ORIGINAL REPORTg SUPPlDENTARY 3

DISTRIBUTION:

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REACTOR (R)

[ FUEL CYCE & SAFEGUARDS (S)

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ACTION:

PRELIMINARY EVALUATION OF THE ATTACHED REPORT INDICATES LEAD RESPONSIBILITY FOR FOLLOWUP AS SHOWN BELOW:

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OTHER l SG THIS DOCUMENT CONTAINS FFMSI POOR QUAUTY PAGES p q180 0N REV:7/9/80 1

VinorNIA Enzcrarc 4.Nn POWER COMPANY Hrenxoxo,VzmoxxzA 20262 July 2, 1980 A9b TO - }bi -00 6 Mr.-Janes P. O'Reilly, Director Serial No. SS2 Office of Inspection and Enforcement N0/FHT:bau U. S. Nuclear Regulatory Cornission Dochet Nos: 50-3.38 Region II 50-339 101 Marietta Street, Suite 3100 50-280 Atlanta, Georgia 30303 50-281 License Nos: NPF-4

. 7 DPR-32 DPR-37

Dear Mr. O'Reilly:

On June 27, 1980, a report was made under the provisions of 10CTR21 con-corning the existence of a non-conservative assu=ption in the cold shutdown desiga basis boron dilution accident analysis in the North Anna FSAR.

In accordance with the reporting requirenents -of 10CFR21, tae following information is subnitted:

A. Nane and address of reporting individual:

Mr. E. A. Baun, Executive Manager

-I.icensing and Quality Assurance P. O. Box 26666 Richnond, Virginia 23261 E. ' Facility, activity and/or conponent affected:

North Anna Power Station Units 1 and 2 Boron Dilution Accident Analyses C.

Nanc or ...- mstructing' the facility or supplying the cooponent, activity or service:

I?estinghouse Electric Corporation, NSSS vendor D.

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-. Description of defect, deficiency.'or failure to comply:

During a review of the FSAR safety analyses for boron dilution accidents, it was deterrined that a non-conservative.assunption was made for the reactor coolant system volume during cold shut-down conditions. The use of an incorrect systen volume yields non-conservative results.

Mr. James P. O'Reilly 2

- Uestinghouse has been perferning a general review of the safety significance of inadvertent boron dilution at shutdcun conditions, and has identified the following concerns:

1. .Therc ccy be insufficient indication of an inadvertent dilution event so as to assure timely action by the operator prior to a return to critical.

2. Without positive operator. acticn, the potential existe for system overpressurization and limited fuel dananc.

I:. Date of' determination of reportability:

' June 27,1980 F. Sinilar couponents, activities, or services:

While the above accident analysis is outside the license design basis for Surry Units 1 and 2, they are also reviewing for susceptibility to inadvertent boron dilution.

G. Corrective action which has been, is being, or vill be taken, the individual responsible and the length of time to coeplete the action:

We have initiated a review of inadvertent boron dilutions for cold or hot shutdown conditions for North Anna Units ' and 2 and Surry Units 1.and 2. A review vill be perforced to icentify and analyze additional boron dilution accidents that may be applicable to these units.

Until the results of our review are available, and pending the results of a generic safety review now being perforced by 1.'estinghouse,

.the following interin actions will be implenented inmediately:

1. During shutdown coaditions and while on the residual heat removal system, a minimum of two shutdown banks vill be available for trip (fully withdrawn) whenever dilution /boration capability exists.

2. Following either source range high flux at shutdown alarn or trip of the withdrawn bank, the operator vill terminate the dilution and intiate boration immediately.

3. 11e source range detectors and high flux at shutdown alarm vill be verified es . operable during shutdown.

II . Other information: ,

-None.

_ _j t o-

!!r. i Jaren F. O'Reilly 3 If you have any: questions or: require additional infor-ation, please

.-contact:this office.

Very truly yours, OrfginaT Sfgned Ey P. , n . 7n ~ n E. R. Sylvia

? tanager-Fuclear Operations and l'aintenance cc: Director,- Office of Insp.>ction and '

. Enforcement (3) .

U. S. Nuclear Regulatory Comr.ission

'4ashington, D. _ C. 20555 e-a Y

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