ML20002C724
| ML20002C724 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 06/26/1972 |
| From: | Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Oleary J US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 8101100788 | |
| Download: ML20002C724 (3) | |
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Mr. John F. O' Leary, Director Re: Docket No 50-155 Directorate of Licensing License No DPR-6 US Atcnic Energy Cor:=ission Wrahington, DC 205h5 Dest Mr. O' Leary:
This is written to apprise you of the failure of off-gas isolation valve CV h015 to close securely eneTh to isolate the off-gas system.
On June 10, 1 a test was conducted to determine the isolation capability of gas isolation valve CV h015 Operation of the valve to the closea position for 30 minutes failed to cause any change in the condenser vacuum of 29" of Hg.
In theory, the closure should cause a decrease in condenser vacuum and subsequent reactor scram at 22" of Hg.
The test was conducted as the result of an inspection made during the refueling outage which disclosed a buildup of foreign de-posits on the vane of the valve which prevented couplete 90 rotation io the closed position. Further investigation revealed that the design of the valve did not allow for tight closure of the valve as evidenced by the lack of proper seating surfaces. The apparent function of the valve was to throttle or reduce flow to the point of losing condenser vacuum and did not require an air tight seal.
A valve that will insure off-gas isolation by providing a leak tight seal vill be procured and installed at a convenient shut-down following procurement. During the interim period, the operating, procedures have been revised to include the following:
3 1.
The off-gas alarm is set at 30,000 uci/s or 1.2 x 10 units (as read on the off -gas recorders and amplifyirg units).
2.
When this value is reached, consideratiot vill be given to a possible load reduction if the activity shows a continual increase.
The Plant Superintendent vill be notified if this occurs.
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Mr. John F. O' Lea'y 2
r US Atenic Ensrgy Commiesion Jun2 26,1972 3.
When an activity of 40,000 uci/s is experienced on the off-gas monitors or 1.h x 103 units (as read on the off-gas recorders and amplifying units), plant load reduction is required to control at or belov k0,000 pei/s (1.4 x 103 units).
3 h.
At an off-gas release rate of 50,000 dei /s (15 x 10 units), the reactor shall be manually scrammed and remain in the shut-down condition until the conditions which brought about the activity rise are corrected.
Following installation of the new valve, an off-gas system isolation test will be conducted to verify the isolation capability of the valve.
Yours very truly, JSR/ sam R. B. Sewell Nuclear Licensing Administrator CC: BHGrier, AEC-COO
.