ML17252A850

Letter Regarding an Occurrence Where a Slight Reactor Coolant System Pressure Transient Was Experienced in the Course of Placing a Reactor Coolant Pump in Service - Indian Point Unit No. 2

ML17252A850
Person / Time
Site:	Indian Point
Issue date:	02/05/1974
From:	Cobean W Con Edison
To:	O'Leary J US Atomic Energy Commission (AEC)
References
Download: ML17252A850 (2)

Text

cc~ ~fnCon1

• l'§tli1. Consolidated Edison Comp~ny ~f Ne~

4 Irving Place, New York, NY 10003 York, Inc.

5 February 1974 DOCKETED USAEC Re: Indian Point Unit.No. 2

~EB 111974 po- ~) Facility Operating License

~*'!;_--;

DPR-26 ---~---

REGULATORY A. 0. -4':'2-:-5 f.4All SECTIO~ .~/!

DOCKET CLERK * . *~), 50-247

.. --< *-,,//

fo -(. /

Mr. John F. o

• l\

• irector Directorate of Licensing

u. S. Atomic Energy Commission Off ice of Regulation Washington, D*. c. 20545

Dear Mr. O'Leary,

The following report is provided pursuant to the requirements of Section 6.12.2(a) of the Technical Specifications to Facility Operating License No. DPR-26.

On January 23; 1974, at approximately 3:38 P.M. a ~light r~~~tor coolant system pressure transient was experienced in the course of placing a reactor coolant pump in. service. The pressure trans-

~ent. was above .the 500 psig Technical Specification limit set borth in Figure 3.1-1 for reactor coolant temperatures less than 220 F.

At the time of the occurrence the reactor was shutdown with all full length control rods fully inserted and- a reactor coolant sys-tem temperature of about 1900F.

In order to heat the reactor coolant system to 547oF, preparatory to returning the plant to service following completion of repairs associated with the November 13, 1973 feedwater line break incident, the first reactor coolant pump was placed in service following pre-scribed procedures. These procedures entailed the.establishment of a nitrogen blanket in the pressurizer to act as a surge volume for the start of the first pump. Upon starting the pump, the re-actor coolant system pressure increased to above 500 psig, as in-dicated by readings of 525 and 510 psig on two drag pressure gages.

The pressure was immediately brought down by operator action to the desired 425 psig.

The pressure transient experienced was much less than those pre-viously reported following* similar reactor coolant pump starts.

The effectiveness of a gas blanket in eliminating or minimizing pressure surges when starting the first PWilP has thus been demon-strated~ This-transient of January 23, 1974 was due to an insuf-ficient amount of nitrogen having been added to the pressurizer and

'}

~.

John F. O'Leary

• 5 February 1974

• - Re: Indiari Point tii~t No. 2 Facility Operating License DPR-26 A.0.-4-2-5 we have changed our procedure to insure that a proper amount ~s inserted in the future.

There are considered to be no safety implications to this occur-rence. There was no damage incurred to any system or component nor was there any reason to expect any as a result of a pressure transient of this magnitude. The pressure limitation of 500 psig at coolant temperatures of less than 2200F is imposed only as a means of insuring additional conservatism in the application of fracture toughness concepts and includes the effects of fast neu-tron exposure which would occur over a two year period of opera-tion. In light of the minimal amount that the limit was exceeded, and the fact that the reactor vessel* has been exposed to only a small fraction of the neutron irradiation assumed, it is consid-ered that the safety of the facility was not compromised by this occurrence.

Very truly yours,

~QC]k.~}

Warren R. Cobean, Jr.GJ Manager - Nuclear Power Generation cc: Mr. James- P. O'Reilly