ML20210Q538
| ML20210Q538 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 02/09/1987 |
| From: | Watson R CAROLINA POWER & LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| HO-870357-(O), NUDOCS 8702170178 | |
| Download: ML20210Q538 (3) | |
Text
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m Cp&L Carolina Power & Light Company HARRIS NUCLEAR PROJECT FEB 0 91997 File Number: SHF/10-13510C Letter Number: HO-870357 (0)
United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 HARRIS NUCLEAR PROJECT UNIT 1 DOCKET NO. 50-400 LICENSE NO. NPF-63 NRC 14-DAY SPECIAL REPORT Gentlemen:
In accordance with Technical Specifications 3.3.3.6 and 6.9.2 for the Shearon Harris Nuclear Power Plant, Unit No. 1, Carolina Power & Light Company hereby submits this Special Report. This Special Report concerns operability of a radiation monitor.
Very truly yours, l
'Baa/ew R. A. Watson Vice President Harris Nuclear Project ONH/skm ~
Enclosure cc:
Dr. J. N. Grace (NRC-RII)
Mr. B. Buckley (NRR)
Mr. C. Maxwell (NRC-SHNPP) h O
DO h
MEM/H0-8703570/ PACE 1/0S1
r ACCIDENT RADIATION MONITOR SPECIAL REPORT
Background:
On January 26, 1987, at approximately 0530, the Waste Processing Building (WPB) Vent Stack 5 wide range gas monitor (WRCM) #RM-1MV-3546-1 experienced a loss of sample flow control alarm. After attempts to restore proper sample flow were unsuccessful, the monitor was declared inoperable and compensatory monitoring methods were initiated by 0600.
Efforts to return the monitor to operable status within 7 days have been unsuccessful. Thus, this special report is submitted pursuant to Technical Specification 3.3.3.6, Action c.
Description of Event:
The WPB Stack 5 accident monitor identified in Tech. Spec.
Table 3.3-10, Item 24.a, consists of a particulate-icdine sampling skid upstream of a wide range (low /mid/high) noble gas monitor.
Sample flow to the monitor is maintained isokinetic with stack flow by means of a flow control valve which takes its signal from flow sensors located in the stack.
An apparent failure in the functioning of this valve or inleakage from some other point caused excessive flow through the monitor and resulted in the alarm.
The compensatory action required by Tech. Specs. is to initiate the preplanned alternate method of monitoring the appropriate parameter within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. For this monitor, the compensatory action consists of monitoring noble gas via the gas channel on the particulate-iodine gas (PIG) monitor (RM-1WV-3546 which samples stack air in parallel with the WRGM. In addition, particulate-iodine continuous samplers were installed at the grab sample connections on the PIC. These actions were completed within 1/2 hour.
Cause:
The cause of this event was equipment failure. A work request was initiated by Radiation Control personnel at 0653 on January 26, 1987 and troubleshooting by Maintenance began the same day. Over the next few days, the excessive flow was suspected to be due to one or more of the following:
- 1) leakage past the instrument air purge solenoid valve;
- 2) improper seating of the flow control valve;
- 3) leakage past the 0-ring packing of the flow control valve; and
- 4) leakage through a split diaphragm on the sample pump.
MEM/HO-8703570/ PACE 2/OS1
r Corrective Actions:
The following actions were taken to repair the monitor:
1.
Tighten all' connections and fittings on the monitor piping.
2.
Install a spare air purge solenoid valve.
3.
Install a spare sample pump.
4.
Replacement of the flow control valve was considered but there was no spare available on-site. This required efforts to repair the existing valve by a) installing replacement 0-rings on the valve stem and, b) filing the valve seat.
These actions have corrected the flow control problem. The monitor has been recalibrated and was returned to service on February 4, 1987.
In addition, spare WRGM flow control valves have been ordered so that repairs can be accomplished more quickly in the event that
-a similar failure occurs in the future.
4 MEM/HO-8703570/ PACE 3/OSI