ML20002C756
| ML20002C756 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 02/15/1974 |
| From: | Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| Shared Package | |
| ML20002C754 | List: |
| References | |
| IEB-74-1, NUDOCS 8101100822 | |
| Download: ML20002C756 (2) | |
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February 15, 1974 Mr. James G. Keppler Re: AEC Bulletin Th-1 Region Director Docket No 50-155 US Atomic Energy Comission License No DPR-6 799 Roosevelt Road Big Rock Point Glen Ellyn, IL 60137
Dear Mr. Keppler:
Your letter of January 11, 1974, requested that DRO Informa-tion Request 74 Abnormal Occurrences in Piping Systems - be addressed at our Big Rock Point Plant. Specif3 cally, infomation
.vas requested regarding any event, condition, malfunction or operating error resulting in unanticipated movement or damage to piping and hanger systems which may not have been deemed as reportable under present AEC regulations (both inside and outside containment), but which have been observed or experienced at Big Rock Point Plant since plant start-up relating to the following:
Question _l, Anomalous and excessive vibrations of piping and/or components in Quality Group A and B systems as defined in Regulatory Guide 1.26.
. Answer During the emergency condenser capacity test of January 12, 1974, unusual vibration of inlet primary system piping was observed when the No 2 loop Discharge Isolation Valve MO-7053 was jogged closed following full-flow operation of the emergency condenser. The primary system was at normal operating pressure of 1335 psig at that time. One loop of the unit was being tested following repair work conducted during the previous outage. The emergency condenser has been used for pressure control and shutdown cooling on many occasions during the plant lifetime and no known observations of this nature have been documented before.
Rovever, normal use of the emergency condenser occurs after the reactor has scramed and the discharge valves close at significantly lover pres-sure and energy output. No known da= age to connecting piping or supports has occurred since all piping supports for systems located outside the pipevay were inspected following the incident. This inspection included Supports FG-16,17,18,19 and RF-17,18,19, 20 and 21 following this incident.
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AEC Bulletin 74-1 I
Docket No 50-155. Big Rock Point February 15, 1974 Question 2_
Unanticipated pipe, component or structural displacement, plastic deformations, or da= age to Quality Group A and B pipe or component support systems.
Answer _
Several overpressures of the Control Rod Drive System occurred during the early years of plant operation. The most significant over-pressure occurred in July 1966 when several pressure instruments on the These over-system were damaged; and a weld at one pipe fitting failed.
pressures occurred during reset of the reactor protection system follow-ing plant shutdown periods or during reactor protection system testing during shutdown periods. The cause was thought to be problems with either the rod pump discharge relief valve sticking or set point drift.
However, analysis of the system revealed that with the 25 gpm positive displacement pumps discharging into a system that suddenly became hard, the relief valves did not act fast enough to limit the pressure spike at the moment of the accumulators becoming fully charged.
Subsequently, the 5018 valve closing stops were adjusted to maintain a flow path at all
, times for these drive pumps. This modification ensures a bypass flow path. No serious overpressures have occurred since this modification.
,uestion 3 Q
Malfunctions of control systems or components which resulted in the imposition of unanticipated dynamic forces upon 'tuality Group A or B piping systems or components.
Answer None experienced.
Your request for information on any containment liner bulges observed is not applicable for Big Rock Point Plant containment sphere.
Yours very truly, WGF/ map Ralph B. Sewell Nuclear Licensing Administrator CC: Asst Director for Construction & Operation Directorate of Regulatory Operations USAEC, Washington, DC l
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