ML17258A113

Forwards Final Evaluation of SEP Topic IX-4, Boron Addition Sys. Evaluation Will Be Basic Input to Integrated Safety Assessment for Facility Unless Changes Are Needed to Reflect as-built Conditions

ML17258A113
Person / Time
Site:	Ginna
Issue date:	08/26/1981
From:	Crutchfield D Office of Nuclear Reactor Regulation
To:	Maier J ROCHESTER GAS & ELECTRIC CORP.
References
TASK-09-04, TASK-9-4, TASK-RR LSO5-81-08-044, LSO5-81-8-44, NUDOCS 8109030220
Download: ML17258A113 (7)

Text

lO'ugust 26, 1981 Docket No. 50-244 LS05 OB-O44 Mr. John E. Maier, Vice President Electric and Steam Production Rochester Gas

& Electric Corporation 89 East Avenue Rochester, New York 14649

SUBJECT:

SEP TOPIC IX-4, BORON ADDITION SYSTEM R.

E.

GINNA

+S a$I'2 198t e 9

Mate NU0SFAE C

Enclosed is a copy of our final evaluation of SEP Topic IX-4.

This

- evaluation incorporates comments provided to us by your letter dated August 6, 1981.

We now consider this evaluation to be final.

This evaluation will be a basic input to the integrated safety assess-ment for your facility unless you identify changes needed to reflect the as-built conditions at your facility.

This topic assessment may be revised in the future ifyour facility design is changed or if the NRC criteria relating to this topic are modified before the integrated assessment is completed.

Sincer ely,

Enclosure:

As stated cc w/enclosure:

See next page Dennis M. Crutchfield, Chief.

Operating Reactors Branch No.

5 Division of Licensing 8f0'F030220 8i0826 I

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Nr. John E. Haier CC Harry H. Voigt, Esquire

LeBoeuf, Lamb, Leiby and HacRae 1333 New Hampshire

Avenue, N. M.

Suite 1100 Mashington, D. C.

20036 Mr. hiichael Slade 12 Trailwood Circle Rochester, New York 14618 Ezra Bialik Assistant Attorney General Environmental Protection Bureau New York State Department of Law 2 World Trade Center New Yo'rk, New York 10047 Jeffrey Cohen New York State Energy Office'wan Street Building Core 1, Second Floor

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Empire State Plaza

Albany, New York 12223 Director, Bureau of Nuclear Operations State of New York Energy Office Agency Building 2 Empire State Plaza

Albany, New York 12223 Rochester Public Library 115 South Avenue Rochester, New York 14604 Supervisor of the Town of. Ontario 107 Ridge Road Mest

Ontario, New York 14519 Resident Inspector R. E. Ginna Plant c/o U. S.

NRC 1503 Lake Road

Ontario, New York 14519 Nr. Thomas B. Cochran Natural Resources Defense Council, Inc.

1725 I Street, N. W.

Suite 600 Mashington, D. C.

20006 U. S. Environmental Protection Agency Region II Office ATTN:

EIS COORDINATOR 26 Federal Plaza New York, New York 10007

,Herbert Grossman, Esq.,

Chairman Atomic Safety and Licensing Board U. S. Nuclear Regulatory Coamission Washington, D. C.

20555 Dr. Richard F. Cole Atomic Safety'nd Licensing Board U. S.'uclear Regulatory Commission Washington, D. C.

20555 Dr.

Emmeth A. Luebke Atomic Safety and Licensing Board U. S. Nuclear Regulatory Commission Washington, D. C.

20555

SYSTEMATIC EVALUATION PROGRAM BRANCH TOPIC IX-4

. BORON ADDITION SYSTEM R.

E.

GINNA PLANT I.

INTRODUCTION Following a LOCA, boric acid solution is introduced into the reactor vessel by two modes of injection.

In the initial injection mode,'orated water is provided from the boric acid.tanks, the refueling water storage tank and the accumulators.

After this initial period, which will last at least 20 minutes for a large break LOCA, and longer for,smaller breaks, the Emergency Core Cooling System (ECCS) is realigned for the recirculation mode. 'n this mode borated water is recirculated from the containment sump to the reactor vessel and.back to the sump through the break.

A portion of the water introduced into the reactor vessel is converted into steam by the decay heat generated in the core.

Since the steam contains virtually no impurities, the boric acid content in the water that was vaporized remains in the vessel.

The concentration of boric acid in the core region will therefore continuously increase, unless a dilution flow is provided through the core.

Without the dilution flow the concentration of boric acid will eventually reach the saturation limit and any further increase in boric acid inventory wi 11 cause its precipitation.

Boric acid deposited in the core.may clog flow passages and seriously compromise the performance of the ECCS.

Topic IX-4 is intended to review the boron addition system, in particular with respect to boron precipi,tation during the long term 'cooling mode of operation following a loss of coolant accident, to assure 'that the ECCS is designed and operated in such a manner that a sufficient throughflow is provided before the concehtration of boric acid will reach its saturation limit.

II REVIEW CRITERIA The plant design was reviewed with regard to Appendix A, 10CFR Part 50, General Design Criteria - 35, "Emergency Core Cooling", which requires that a system to supply abundant emergency core cooling shall be provided.

In addition, the plant design was reviewed with regard to 10CFR 50.46, "Acceptance Criteria for Light Water Nuclear Power Reactors",

and Appendix K to 10CFR Part 50 "ECCS Eval-uation Models", which set forth the requirements to maintain eoolable core g ometry and to provide long-term core cooling; the basis for the boron precipi-tat ion revi ews-III RELATED SAFETY TOPICS Topic VI-7.A.3 reviews the ECCS actuation system with respect to the testing for operation and design performance of each

'component of the system.

Topic VI-7.B reviews the procedures for ESF switchover from injection to recirculation mode

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IV.

REVIEW GUIDELINES There are no unique SRP sections that deal with this issue.

The primary criterion used for review of this system was discussed in a rhemo dated January 21, 1976 entitled, "Concentration of Boric Acid in Reactor Vessel During Long Term Cooling

-. Method for Reviewing Appendix K Submittals."

V.

EVALUATION The guidelines for this review are contained in Reference 1, which is a

memo describing the methods used to review boric acid buildup during post-LOCA long-term cooling.

There is no SRP section covering this topic.

, The Ginna reactor is different than current Mestinghouse designs in two areas that affect boron precipitation.

One is that the residual heat removal (RHR) injection feeds directly into the upper plenum rather than into the cold or hot legs.

This means that a switchover from cold leg to hot leg injection cannot be used to dilute boron in the RHR system.

The second area of difference is that several valves may be flooded following a

LOCA.

Once flooded, the.valves may not stork and no. credit is given for operation of flooded valves.

The valve lineup on the Ginna high head injection system is set for cold leg injection with power removed to prevent spurious operation of the flooded valves.

This means that switch-over from cold to hot leg injection cannot be used to prevent boron pre-cipitation in the high head injection system.

To prevent boron precipitation, the Ginna plant utilizes simultaneous injection from the RHR and high head systems.

The simultaneous injection takes place within 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br /> following the LOCA; and requires the primary system to be cooled to RHR conditions.

However, even if the system is not cooled to RHR conditions, it is unlikely that boron precipitation would occur since the solubility is greater at higher temperatures.

Furthermore, cooldown to RHR operating conditions will not be a problem with a large break LOCA.

VI.

CONCLUSION The Ginna method of preventing boron precipitation is to simultaneously inject into the cold legs (high head system) and upper plenum (RHR system).

This will provide sufficient dilution flow for both hot and cold leg breaks.

Based on our review and using staff criteria referenced earlier,

.we conclude that the Ginna method for prevention of boron precipitation is acceptable.

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REFERENCES J'.

Memorandum for Thomas M. Novak, Chief, Reactor Systems Branch from K. I. Parczewski, Reactor Safety Branch dated January 21, 1976.

2.

Letter to L. D. White, Jr., Rochester Gas and Electric from A. Giambusso, dated May 14, 1975.

3.

Letter to R. A. Purple, NRC from L. D. White, Jr.,

RG&E dated May 20, 1975.

4.

Letter to R. A. Purple, NRC from L. D. White, Jr.,

RG&E dated May 30, 1975.

5.

Letter to L. D.

6.

Letter to B.

C.

7.

8.

Letter to T.

M.

April 1, 1975.

Letter to B.

C.

9.

Letter to B.

C.

White, Jr.,

RG&E from R. A. Purple, NRC dated July 3, 1975.

Rusche, NRC from L'.,D. White, Jr.,

RG&E dated April 1, 1975.

Novak, NRC from C. L. Caso, Westinghouse CLC-NS-309 dated

Rusche, NRC from L. D. White, Jr.,

RG&E dated April 30, 1975.

Rusche, NRC from L.

D. White, Jr.,

RG&E dated May 13, 1975.