3F0198-04, Special Rept 97-08:on 971208,mid Range & High Range Noble Gas Stack Monitors Found to Be Inoperable Greater than Seven Days.Cables to low-medium-high Valve Controllers re-connected Inside Radiation Monitoring Panel

Special Rept 97-08:on 971208,mid Range & High Range Noble Gas Stack Monitors Found to Be Inoperable Greater than Seven Days.Cables to low-medium-high Valve Controllers re-connected Inside Radiation Monitoring Panel

ML20198D923
Person / Time
Site:	Crystal River
Issue date:	01/03/1998
From:	Grazia R FLORIDA POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
3F0198-04, 3F198-4, 97-08, 97-8, NUDOCS 9801080324
Download: ML20198D923 (4)

Text

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. January 3,1998 3F0198-04 U.S. Nuclear Regulatory Comrnission Attn: Document Control Desk Washington, D.C. 20555-0001

Subject:

SPECIAL REPORT 97-08, INOPERABLE NOBLE GAS MONITORS

Dear Sir:

Please find the enclosed Special Reoort 97-08, which discusses the details of the Mid Range and High Range Noble Gas Stack Monitors being inoperable for greater than sai n days, the actions taken, and the date of return to service. This report is being submitted in accordanca with Florida Power Corporation's Off site Dose Calculation Manual.

Sincerely,

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R. E. Grazio 6_

Director Nuclea.' Regulatory Affairs REG /rlm Enclosures /

t . Senior Resident inspector NRR Project Manager Regional Administrator, Region II

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9801080324 980103 PDR ADOCK 05000302 S PDR ,

'U.S. Nuclear Regulatory Commission 3F0198-04 Page 2 ENCLOSURE 1 SPECIAL REPORT ON MID RANGE AND HIGH RANGE NOBLE GAS STACK MONITORS FOUND TO BE INOPERABLE GREATER THAN SEVEN DAYS This special report is being submitted in accordance with the Crystal River Unit 3 Off-Site Dose Calculation Manual, Revision 22. The purpose of this report is to provide the details of the Mid Range and High Range Noble Gas Stack Monitors being inoperable for greater than seven days, the actions taken, and the date of retum to service.

DESCRIPTION On December 8,1997, while FPC personnel were removing spare cables from the Radiation Monitoring (RM) panel, two disconnected cables were discovered that are required to be connected to the Low-Medium-High (LMH) valve controllers of the Atmospheric Radiation Monitoring System. These cables carry signals from Radiation Monitors RM-A1 and RM-A2 Low Range Noble Gas Monitors to their respective LMH valve controllers, in the event the Low Range Noble Gas Monitors exceed approximately 3/4 scale, the LMH valve controllers shift from the Low Range detectors to the Mid and High Range detectors. These cables were improperly disconnected during a modification performed in 1996 which removed unused cables associated with the Emergency Dose Assessment System.

Channel alarms and protective functions are initiated by the Low Range detectors. Operators would be alerted to increasing radioactivity levels during a postulated event. Since the cables were disconnected, the LMH valve controllers would not have automatically transferred to the Mid and riigh Range detectors and would not have indicated higher radioactivity levels without direct operator action. Abnormal Procedure AP 250, " Radiation Monitoring Actuation" directs the operatois to switch the LMH valve controllers to " Auto"(from their normal " Manual" position) on an increasing signal from the Low Range Monitors in anticipation of the switchover to the Mid arid High FanGe detectors. it is reasonable to assume the operator's attention would be focused on the Low Range Monitors and a failure to switchover wou!d be promptly identified. If the switchover fa3ure is ide< d, manual control of the LMH valve controllers is available. The Mid and High Range i . ors remained operable and would have responded to increasir'g contamination if manually selected.

The RM-A1 Mid Range and High Range Mon; tor is required to be operable during Reactor Building (RB) purge. The RM-A2 Mid Range and High Range Monitor is requl red to be operable to monitor the Auxiliary Building stack discharge when the plant is above MODE S. A determination of inoperabit;ty was based on the inability of the system to automatically perform the switchirig function and a lack of clear guidance to the operators that manual operation of the LMH valve mntrollers 'vas necessary. The period of inoperability extended from approximately May 1996 to December,1997, whenever the plant was above MODE 5 or the RB Purge was in progress Periodic testing would not have detected the problem because the releva7t test connections were beyond the point where the conr'ections had been lifted.

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3F0198 04 Page 3 ACTIONS TAKEN OR PLANNED-The cables to the LMH valve controllers were re-connected inside the Radiation Monitoring Panel. A functional test of the automatic transfer function of the LMH valve controllers was satisfactorily completed on December 30,1997. Preventive Maintenance procedure PM-292,

- " Checkout of the F's?s Noble Gas Mid and High Range Detector Valves and Valve - .

. Controllers', will be revisa prior to its next oerformance to appropriately test the automatic transfer function of the LMH valve controllers.

The disconnected cables were discovered during a planned outage and inspection of the Radiation Monitoring Panel. The panel was being inspected for proper cable terminations, loose wiring, improperly insulated ground wires and foreign material. The condition of the panel and accessibility of circuitry for future maintenance was improved.

EXPECTED RETURN TO SERVICE The system was retumed to service upon successful completion of the functional test on December 30,1997.

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l U.S. Nuclear Regulatory Commission 3F0198-04 Page 4 ENCLOSURE 2 RESPONSE COMMITMENT DUE DATE SEC .10N Pat,c 3 Preventive Maintenance procedure PM-292, November 1,1999

" Checkout of the Pass NotAe Gas Mid and High Range Detector Valves and Valve Controllers", wiil be revised prior to it's next performance to appropriately test the automatic transfer function of the LMH valve controllers.

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