ML20084B013

AO 3-2-5:on 730518,pressure Transient within RCS Experienced Due to Closure of Certain Air Operated Valves in Reactor Coolant Letdown Sys.Caused by Moisture Freezing in Air Supply Line Refrigerant Dryer of Instrument Air Sys

ML20084B013
Person / Time
Site:	Indian Point
Issue date:	05/25/1973
From:	Caldwell W CONSOLIDATED EDISON CO. OF NEW YORK, INC.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
References
A-3-2-5, A0-3-2-5, NUDOCS 8304060070
Download: ML20084B013 (2)

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ConWducJ Eden Company of Ncw York. Inc.

4 i n ng Place. New York. N Y 10003 Tc:eptwr.e (212) 400 5181 May 25, 1973 Re: Indian Point Unit No. 2 Facility Operating L g (A DPR-26 f.9

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Mr. John F. O' Leary, Director />

i-I. - i Directorate of Licensing U.S Atomic Energy Commission E Y3flfg7 3 9 i j Washington, D. C. 20545

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Dear Mr. O' Leary:

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The following report of Abnormal Occurrence No. 3-2-5'is

. , provided pursuant to the requirements of Section 6.6.1 of b'] / ,f the Technical Specifications to Facility Oparating License No. DPR-26. \

/'U On Friday, May 18, 1973, the Reactor Coolant ~ System was 3 i 'l-/ in the process of being heated up in order to conduct a I'.

U hydrostatic test. At the time, four reactor coolant pumps were in service with Reactor Coolant System con-ditions of approximately 440 psig, 13OoF, 1980 ppm boron and all control rods inserted. The reactor had J

[M, not yet been brought to initial criticality.

At 0552 hours0.00639 days <br />0.153 hours <br />9.126984e-4 weeks <br />2.10036e-4 months <br />, a pressure transient within the Reactor

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Coolant System was experienced due to the closure of certain air operated valves in the reactor coolant

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letdown system. The reactor coolant pumps and charging pump were shutdown to prevent any further pressure in-creases. Closure of,the valves resulted in Reactor Coolant System pressure increasing to approximately 575 psig. An investigation revealed that moisture in an air supply line at the refrigerant dryer of the Instrument Air system had frozen. The alternato dryer was placed in _ervice s with subsequen h e bst'551~iThme W of the proper pressure within the ' Instrument' Air System.

Reactor Coolant System pressure was then returned to normal.

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Mr. John F. O'L6uty May 25, 1973 .

Investigation as to the cause of the freeze-up disclosed that the suction service valve to' the refrigerant com-

• pressor had been backseated to eliminate gland leakage.

Backseating of this valve, however, also resulted in isolation of the low suction pressure shutoff controller for the compressor and this caused it to remain in ser-vice allowing moisture in the air line to freeze, and eventually interrupt the air supply.

To prevent recurrence, a relocation of the suction pres-

. sure controller tap to a point directly on the suction of the compressor is to be accomplished. This will allow backseating of the valve to prevent freon leakage along 5 the valvo stem, without affectir.g the control system. In j the interim, signs have been installed at the dryers prohibiting full-backseating of the subject valves while the compressor is in service.

The safety implications of this occurrence are not con-sidered nignifi ant.- There was no damage incurred to any system or c mponent nor was there any reason to ex-pect ,any as a result of a pressure transient of this magnitude. The pressure limitation of 500 psig, at coolant temperatures less than 2200F, is imposed only as a means for providing additional conservatism in the application of fracture toughness concepts. The limit also includes the effects of fast neutron exposure which would occur over a two year period of operation.

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In lighttof the above, it is considered that' the safety i of the facility was not comprised by this occurrence.

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Very truly yours,-

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• 1 i CC - Mr. James P. O'Reilly .

Regulatory Operations ,

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01207 FR DC NEWYORK NY 34 c5-21742P EDT ["]q' PMS J AMES P OREILLY DIRECTOR s n i RENLATORY OPER ATIONS REGION I bjl 4

US ATOMIC ESERGY COMM e <

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A DE AR *R ORE ILLY-IN ACCORDANCE WITH THE REGUIREMENTS OF TECHNICAL SPECIFICATION l 5. 5.1:$ FOR FACILITY OPERATING LICENSE NO l DPR-25 VE WISH TO INFORM YOU OF AN ABNORMAL OCCURRENCE WHICH VAS ,

ICENTIFIED ON MAY 18,1373 AT 0552 HOURS-

, IN THE COURSE OF HEATING UP THE REACTOR COOLANT SYSTEM i l PREPARATORY TO THE CONDUCT OF A HYDROSTATIC l TEST , A PRESSURE TR ANSIENT TO ABOUT 575 PSIG r

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i l WAS EXPERIENCED DU TO CLOSURE OF CERTAIN AIR OPERATED VALVES ASSOCI ATED WITH THE CHARGING AND LETDOWN SYSTEM UDON LOSS OF CONTROL AIR.

OUR PRELIMINARY INVESTIGATION INDICATES THT THE LOSS OF CON TROL AIR WAS THE RESULT OF A FREEZE UP OF THE AIR SUPPLY LINE AT THE REFRIGER ANT DYRER. AT THE TIME OF THE TR ANSIENT, THE RE ACTOR COOLANT SYSTEM WAS A APPROXIMATELY 440 PSIG.

AND 130 DEGREES F WITH FOUR REACTOR COOLANT PUMPS IN SERVICE AND ALL CONTROL RODS FULLY INSERTED.

I l, THERE WAS NO DAMAGE TO ANY SYSTEM OR COMPOPENT NOR WAS -.

l t THE RE ANY REASON TO EXPECT ANY AS A RESULT OF THE PRESSURE TR ANSIENT.MR A F AS ANO OF YOUR OFFICE VAS INFORMED OF THE OCCURRENCE BY MR JOHN MAXEPEACE BY TELEPHOPE ONMAY18 1973

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l IN ACCORDANCE WITH THE REQUIRENNTS OF TECHNICAL SPECIFICATION 3.2 NOTIFICATION OF THE VICE CHAIRMAN OF THE NUCLEAR FACILITIES

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SAFETf COMMITTEE HAS BEEN MADE. '

W ARE CURRENTLY INVESTIGATING THE CAUSE OF TIC  !

CCCURRENCE AND WILL ADVISE YOU OF CLR FI*0!NGS AND CORRECTIVE ACTION TAKEN IN A WRITTTEN REPORT I'!

VHICH WILLBE SUBMITTED WITHIN THE REUIRED TEN (10) DAYS I

J YOURS TRULY WILLI AM E CALDVELL 3 i

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Licensee: Consolidated _ Edison Company _

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rabar.. tet Docket No.. 50-247

!? i f S .U B Abnor~al Occurrence: Telegram dtd 5/21/73

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at: Cent ral riles (1) t.ru The attached report from the subject licensee _is Pecul at ory Standar n (3)

Dir. of Licensing (13 i forwarded in accordance with R0 Manual Chapter 1000 1( peer * . ^ G iamfi l#te I 6 AL,.S ktMA.E5 The action taken by the licensee is considered can appropriate. Followup will be perfomed during _

the next inspection a's apr,opriate. capics of n o g. . . . . ,,, ~ , , .t . ., s the report have been forwarded te, the PDR, Local

'<0 : 1 PDR, NSIC, DTIE and State representatives. The licensee will submit a 10 day written report to PtsAst ful DA fl Licensing.

UM OTHER ME FOR sOpqTKJsual REM APK5 . Gro 1971 0 en ea n A

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