ML20084A215

RO 50-237/76-66:on 761113,HPCI Sys Injection Valve 2-2301-8 Failed.Valve Repairs to Be Completed at Next Outage

ML20084A215
Person / Time
Site:	Dresden
Issue date:	12/13/1976
From:	Abrell G COMMONWEALTH EDISON CO.
To:	Ziemann D Office of Nuclear Reactor Regulation
Shared Package
ML20084A199	List: 05000237/LER-1976-066, Updated LER 76-066/01T-1:on 761113,during Maint Outage,Hpci Injection Valve M02-23018 Found in Closed Position W/Valve Stem Severed.Caused by Mechanical Overstress of Stem.Stem Replaced 05000237/LER-1976-066-01, /01T-0:on 761113,during Maint Outage,Hpci Injection Valve M02-2301-8 Found in Closed Position W/Severed Stem.Cause Undetermined.Valve Clamped in Open Position ML20084A215 ML20084A261
References
RO-50-237-76-66, NUDOCS 8304050131
Download: ML20084A215 (2)

Text

-

W(,h

%. . - .c ~ -- y

[ T' )O I Plaza. Chicago, tilinois /

\ O "7 Address Reply to: Post Offica Box 767 V Chicago,litinois 60690

~

December 13, 1976 i . %' 111 SEC Director of Nuclear Reactor Regulation N C -20 p'OC Attn: Mr. Dennis L. Ziemann, Chief 11 Operating Reactors - Branch 2 Division of Operating Reactors Q]%[fkID%

/

U.S. Nuclear Regulatory Commission < /

Washington, D.C. 20555 2T -

Subject:

Dresden Station Unit 2 High Pressure Coolant Injection (HPCI)

System Flow Testing 7 NRC Docket No. 50-237 OQ<

p Reference (a) : Dresden Station Reportable Occurrence No. 50-237/76-66.

Daar Mr. Ziemann:

Reference (a) reported the failure of the high pressure coolant injection (HPCI) system injection valve 2-2301-8. In order to maintain the HPCI system operability, this valve has been placed in the open po-sition. Although thic line-up maintains the injection capability of the HPCI system, it makes more difficult the complete surveillance flow testing.

Section 4.5.C.1 requires flow testing at reactor vessel pressure between 1150 and 150 psig. Although no interval is specified for this flow testing in the Technical Specifications, this flow testing has b een conducted routinely on a quarterly basis. The flow test conducted during this quarter included the usual run at 900 psig vessel pressure but the 1150 psig test was deferred. This test was not conducted at this time

% in order to avoid the possibility of injecting the HPCI into the vessel.

0@@ The HPCI water supply is from the storage tank and is cold, oxygenated 88 water. Although of react'or quality in terms of its chemistry, it is y not desirable to inject this water into the vessel under operating con-

,o ditions considering feedwater thermal cycles, accelerated corrosion due gg to oxygenated water, and the potantial for a flux spike.

00 o< Conducting the flow test at 900 psig provides adequate assurance om of the HPCI operability when the measured parameters of pump flow, pump OOm pressure, and turbine speed are compared to previous test results. This shows that the pump is operating on its established performance curve.

I Past operating history reveals no significant deterioration of ti the pump and turbine performance since 1970, certainly no deteriora &on, fo COPY SENT REGION + ~ N 12835 A

y l

(] Comm:nwrith Edison C December 13, 1976 Mr. Dennis L. Ziemann 1

is to be expected in the interim period until full pressure testing is resumed.

Repairs of the 2-2301-8 motor operated valve is to be completed at the next outage of approximately three days duration which will occur in any case in late April at a hydraulic snubber inspection. This means that possibly one additional abbreviated flow test will be conducted prior to complete the restoration of the system on our present quarterly flow testing schedule.

One (1) signed original and 39 copies are provided for your use.

Very truly yours, Q' b '

~ G. A. Abrell Nuclear Licensing Administrator Boiling Water Reactors

/

l l

l l

- - -