ML19347C773
| ML19347C773 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 09/18/1975 |
| From: | CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | |
| References | |
| AO-19-75, NUDOCS 8102170044 | |
| Download: ML19347C773 (1) | |
Text
'
e ABNORMAL OCCJREENCE REPORT Big Rock Point Plant 1.
Report No: A0-19-75, Docket 50-155 2a.
Report Date: September 18, 1975 2b.
Occurrence Date: 1962 - 1975 3
Facility: Big Rock Point Plant h.
Identification of Occurrence: Reactor clean-up system valves design deficiency.
5 Conditionn Prior to Occurrence: Power Operation 6.
Description of Occurrence:
Review of valve application data for valves CV-4091, CV h092, CV-h093 and the manual isolating valves in series with CV-h092 and CV-h093 revealed that these valves have one of two deficiencies depending on the seat and seal materials.
n.
If the valves contain nylon-neoprene seats and seals, they are rated at only 180 F.
Since these valves are containment isolation valves, they should be rated to at least 235 F.
s b.
If the valves contain teflon seats and seals, they are rated at only 1000 psi by the manufacturer and thus vould be significantly below primary system pressure design requirements of 1700 psia.
7 Designation of Apparent Cause of Occurrence: Original plant design deficiency.
8.
Analysis of Occurrence: At the present time, all five valves are closed and there are no indications of external leakage on CV-h092, CV h093 or the two manual isolation valves associated with them.
In addition, the manual isolation valves located outside containment have also been closed.
The valve bodies and flanges are rated at 2000 psig.
9 Corrective Action: At the present time, we are reviewing valve require-ments to determine if replacement valves can be obtained. All five valves were leak tested satisfactorily at greater than containment design pres-sure September 12, 1975 10.
Failure Data: Valves are Worcester, Model h66T (Teflon),1-1/2" ball valves or Model hk6 YN (nylon seat, neoprene seal), 1-1/2" ball valves, or a combination of these two types.
f s
Flo476o@'