ML032541184
| ML032541184 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 09/04/2003 |
| From: | Cooper D Nuclear Management Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML032541184 (4) | |
Text
Commted to NudearExce .
Palisades Nuclear Plant Operated by Nuclear Management Company, LLC September 4, 2003 U S Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 PALISADES NUCLEAR PLANT DOCKET 50-255 LICENSE No. DPR-20 SPECIAL REPORT OF INOPERABILITY OF ONE CHANNEL OF STACK GAS EFFLUENT SYSTEM Palisades Offsite Dose Calculation Manual, Appendix A, Table A-1, Action 4, requires that a Special Report be submitted to the NRC within 30 days when the Hi Range Noble Gas Monitor, RIA-2327, is inoperable and not restored to operable status within 7 days.
The report is to outline the actions taken, the cause of the inoperability, and the plans and schedule for restoring the channel to operable status. The required report is attached.
This letter contains no new commitments and no revisions to existing commitments.
Douglas E. Cooper Sr. Vice-President - Group Operations CC Regional Administrator, USNRC, Region Il Project Manager, Palisades Nuclear Plant, USNRC, NRR NRC Resident Inspector - Palisades Nuclear Plant Attachment 27780 Blue Star Memorial Highway
- Covert, Michigan 49043-9530 Telephone: 269.764.2000 ) ei-paa,
ATTACHMENT NUCLEAR MANAGEMENT COMPANY, LLC PALISADES NUCLEAR PLANT DOCKET 50-255 September 4, 2003 SPECIAL REPORT OF INOPERABILITY OF ONE CHANNEL OF STACK GAS EFFLUENT SYSTEM 2 Pages Follow
SPECIAL REPORT OF INOPERABILITY OF ONE CHANNEL OF STACK GAS EFFLUENT SYSTEM Hi RANGE NOBLE GAS MONITOR RIA-2327 The Hi Range Noble Gas Monitor, RIA-2327, is one of four instruments associated with the Stack Gas Effluent System. RIA-2327 is a post-accident monitor used to monitor noble gasses. This channel is activated and placed into service in the event of a high alarm signal from the normal range noble gas monitor, RIA-2326.
CAUSE OF INOPERABILITY On August 6, 2003, at 2120 hours0.0245 days <br />0.589 hours <br />0.00351 weeks <br />8.0666e-4 months <br />, the Radioactive Gas Effluent Monitoring (RGEM)
System was declared inoperable when the indication on stack gas flow recorder FR-2318 lowered, tripping the RGEM sample pumps. Actual stack flow rate was not affected.
The RGEM system is designed to obtain an isokinetic sample. The system receives a reference signal, which is proportional to the stack flow rate. When the stack flow rate on recorder FR-2318 indicated a zero stack flow rate, the RGEM sample flow rate also went to zero, which initiates a low flow signal and trips the system.
ACTIONS TAKEN On August 7, 2003, the sensing lines were purged. Work order history showed that purging the sensing lines (condensation build up) had corrected low flow indications on FR-2318 in the past. This effort did not resolve the problem. FR-2318 continued to periodically spike downward from the normal stack flow rate of 72,000 cfm to zero cfm.
On August 8, 2003, monitoring of the outputs from stack flow transmitter FT-1 818 and the square root extractor was initiated to determine the source of the failure. A current source was used to simulate a 1.5 cfm sampling flow rate and the RGEM unit was again functional. Stack flow rate indications on FR-2318 returned to normal, and remained normal during a 10-day monitoring period.
On August 18, 2003, the loop for FT-1818 to RGEM was restored to normal configuration and the monitoring equipment was removed, however, RGEM remained inoperable.
On August 19, 2003, at 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br />, recorder FR-2318 spiked low numerous times causing the RGEM system to again shut down.
On August 20, 2003, it was identified that when the terminal connections on the rear of stack effluent gas flow monitor, FM-1818, were pressed, the output of FM- 818 would spike low, duplicating the observed spiking phenomena. The bus bar that connects terminal II to terminal 6 was removed, cleaned, and reinstalled.
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SPECIAL REPORT OF INOPERABILITY OF ONE CHANNEL OF STACK GAS EFFLUENT SYSTEM SCHEDULE FOR RETURN TO SERVICE Monitoring continued until August 22, 2003. No further problems with the flow loop occurred. The RGEM system was returned to operable status on August 22, 2003, at 1035 hours0.012 days <br />0.288 hours <br />0.00171 weeks <br />3.938175e-4 months <br />.
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