ML20196A452
| ML20196A452 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 02/01/1988 |
| From: | Frisch R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| NUDOCS 8802050053 | |
| Download: ML20196A452 (2) | |
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l Consumers POW 8r L
ME AUGANIAM'S MtdNiftE55 General officos: 1945 West Parnall Road, Jack son, MI 49201. (517) 788-0550 l
February 1, M88 l
i Nuclear Regulatory Commission Document Control Desk l
Washington, DC 20555 DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT -
STR0KE TESTING OF MO-7071 Inspection Report No. 50-155/87022 identified a NRC concern that while l
performing T30-22 valve MO-7071 was being tested in a manner which did not i
assure that maximum differential pressurr existed across the valve during l
testing. During performance of T30-22, at that time, it was noted that back l
1eakage through the "telltale" between MO-7070 and VPI-303 provided evidence l
that the piping between VPI-303 and MO-7071 was depressurizing (via leakage through V?I-303) and this resulted in MO-7071 being tested against maximum l
differential pressure in the reverse direction. Consumers Power Company committed to revise the test procedure as discussed with the inspectors and to submit a copy of the revised test procedure within sixty days.
A change was made to T30-22 to include the following step:
"Verify that pressure between check valve VPI-303 and MO-7071 has bled off by observing the following: With MO-7071 open observe the flow from the telltale between MO-7070 and MO-7071. Then, after closure of M0-7071, observe that the flow from the telltale decreased l
indicating depressurization of the spool piece between VPI-303 and M0-7071."
The following observations were made recently while performing the revised T30-22 which requires additional action; 1.
MO-7070 was opened and a steady stream was noted from the telitale.
2.
M0-7070 was closed and the stream from the telltale stopped completely.
3.
MO-7071 was opened and no flow through the telltale was noted.
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4.
M0-7071 was closed with no change in flow noted, f0
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PDR ADOCK 05000155 G
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o Nuclear Regulatory Commission 2'
Big Rock Point Plant i
Stroke Testing of MO-7071 February 1,- 1988 i
The abo *;e sequence indicates that check valve VPI-303 is holding and pressure is being trapped between VPI-303 and MO-7071.
Under this condition the valve i
may be required to function with a large differential pressure across the valve (Reactor pressure trapped between the valves and atmosphere pressure in the Reactor vessel) during an accident condition.
It is believed that the i
first test of M0-7071 after a start-up already shows that the valve will stroke with this large differential pressure. This is due to the fact that there should be no pressure between VPI-303 and MO-7071 af ter start-up.
Since it has been discovered that the change to T30-22 previously discussed with the NRC has been found to not perform its intended purpose it is proposed to change the shutdown procedure to stroke M0-7071 when the reactor pressure is less than 50 psig during plant shutdowns. To demonstrate operability, this
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will permit stroking MO-7071 with a large differential pressure trapped between MO-7071 and VPI-303 as would be the case during an accident condition.
I This change will be implenented during the next refueling shutdown currently scheduled for April 1988.
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Ralp R Frisch i
j Senior Licensing Analyst i
i CC Administrator, Region III, NRC i
NRC Resident Inspector - Big Rock Point Plant i
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