ML18051A798

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Notifies of Variance from Requirements of NUREG-0737.Recent Review of Stack Gas Monitors Revealed That Display Capabilities Not in Accord w/NUREG-0737,Item II.F.1.1
ML18051A798
Person / Time
Site: Palisades, Big Rock Point, 05000000
Issue date: 02/20/1984
From: Vandewalle D
CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To: Crutchfield D
Office of Nuclear Reactor Regulation
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-2.F.1, TASK-TM NUDOCS 8402230012
Download: ML18051A798 (2)


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@; David J VandeWelle Direcror of Nuclear Licensing General Offices:

  • 1945 West Parn~ll Road, Jackson, Ml 49201 * (517) 788-1636 February 20, 1984
  • - *. J Dennis M Crutchfield, Chief Operating Reactors Branch No 5 Nuclear Reactor Regulation US Nuclear Regulatory Commission Washington, DC 20555 DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT -

DOCKET 50~255 - LICENSE DPR PALISADES PLANT -

STACK GAS MONITOR VARIANCE FROM THE DISPLAY CRITERION FOR NUREG-0737 ITEM II.F.1.1 (NOBLE GAS EFFLUENT MONITOR)

  • .. ** This letter is to notify you of a variance from the requirements of NUREG-0737. The Big Rock Point Plant and Palisades Plant stack gas monitors were installed to satisfy the requirements of NUREG-0737 items II.F.1.1 and II.F.1.2. A recent review of these monitors revealed that their display capabilities are not in accordance with the display criteria specified in NUREG-0737, Table II.F.1-1. This criterion states that the noble gas effluent monitor display shall be continuous and recorded as equivalent Xe-133 concentrations or as uCi/cc of actual noble gases. The Big Rock Point and Palisades Plant s.tack gas monitors employ ~ beta scintillation detector to measure noble gas encountered during normal operation, and an ionization chamber for higher noble gas concentrations (up to 10 5uCi/cc) encountered during accident conditions. The output of the beta scintaillation detector is displayed in units of "counts per minute" (cpm), and the ionization chamber output is displayed in units of mR/hr.
  • The conversion from monitor response to uCi/cc is dependent on the particular mixture of noble gas radionuclides being monitored. The_ particular mixture will change with core burnup, the rate of release of noble gases from the core, and time after shutdown. Since the-Big Rock Point Plant and Palisades Plant monitors are not designed to correct for these changes, a display of the monitor output in equivalent Xe-133 concentration or uCi/cc of actual noble gases is not possible. In order to properly account for changes in the concentration of noble gas radionuclides, Consumers Power has developed a set of curves which convert the displayed monitor response to a release rate in units of uCi/s for both the beta scintaillation detector and the ionization

., .* chamber. The proper curve is selected based on which detector is in use and on the results of a gamma spectrum analysis of the effluent gas.

oc0284-0338a142 8402230012 840220 PDR ADOCK 05000155 P PDR

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1 D M Crutchfield, Chief 2 Big Rock Point & Palisades Plants

.l Stack Gas Monitor Variance

-~ February 20, 1984

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'! For this reason, Consumers Power Company believes that the existing stack gas

.! monitor displays, used with the associated curves, fully satisfy the intent of the display criterion specified in NUREG-0737, Table II.F.1-1.

      • ~

David J VandeWalle Director, Nuclear Licensing CC Administrator, Region III, USNRC NRC Resident Inspector-Big Rock Point oc0284-0338a142

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