ML20247K274

Special Rept:On 890508,wide-range Noble Gas Stack Monitors RM-063L,RM-063M & RM-063H Removed from Svc for Calibr of Flow Control Circuit & Not Returned to Svc within 7 Days. Caused by Malfunctioning Dahl Controller

ML20247K274
Person / Time
Site:	Fort Calhoun
Issue date:	05/23/1989
From:	Morris K OMAHA PUBLIC POWER DISTRICT
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LIC-89-447, NUDOCS 8906010260
Download: ML20247K274 (2)

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Oranha Public Power District i 1623 Harney Omaha. Nebraska 68102 2247  !

May 23, 1989 402/536-4000  ;

LIC-89-447 l J

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i U. S. Nuclear Regulatory Cummission l Attn: Lanument Control Desk Mail Station P1-137 Washington, DC 20555 )

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References:

1. Docket No, 50-285 )

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2. Letter OPPD (K. J. Morris) to NRC (Document Control Desk) dated February 7,1989 (LIC-89-161), Special Report on Inoperability of Main Steam Line Radiatiois Monitor RM-054, and Wide Range Noble Gas Stack Monitors RM-053L and RM-053H ,

for Post-Accident Monitoring

3. Letter OPPD (K. J. Morris) to NRC (Document Control Desk) dated February 23,1989, (LIC-89-227), Special Report on 1 Inoperability of Wide Range Noble Gas Stack Monitor RM-063M for Post-Accident Monitoring )

4. Letter OPPD (K. J. Morris) to NRC (Document Control Desk) dated March 17,1989 (LIC-89-246), follow-up to Special Report on Inoperability of Main Steam Line Radiation Monitor RM-064 and Wide Range Noble Gas Stack Monitor 4 RM-063H for Post Accident Monitoring

SUBJECT:

Special Report on Inoperability of Wide Range Noble Gas Stack l Monitors RM-063H, RM-063L, and RM-063M for Post-Accident Monitoring Gentlemen:

1

, Omaha Public Power District (OPPD) submits this reocrt pursuant to the require- I merts of Fort Calhoun Stati0n Technical Specification 2.21, " Post-Accident I Monitoring Instrumentation." Table 2-10, item 2 requires that a minimum of one 1 channel for each wide range nobis gas stack monitor RM-063L, RM-063M and l 3

RM-063H be operable in Nodes 1, 2 ar.d 3. If the number of operable chanaels is l 1ess than the minimum operable char.aels requireranh OPFD niust either restore j the moperable chaqr:els to operable 5thtgs within seven dayr of the event, or i prepars and submit a Suecial Report to the Cofrnistion pursuant to Technical Specification 5.9 3 within 14 dayt icM owing the eveht. l fieferences 2 and 3 discussed the inoperability of monitors RM-063L, RM-063M, l RM 063H and RM-064 and indicited that these ronitors would bs operable by March  ;

17, 1989. Reference 4 indicated that Monitors RM-003L and RM-0638 were in fact i returned to service on March 13, 1989, and that RM-053H and RM-064 were  !

exper.ted to be fully operational by May 15, 1989. '

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U, S etclnr Regulatory Ccnmiss;on LBC-89-447'

( Page 2 RM-064 was then repaired and calibrated,. had applicable surveillance testing completed on it, and was returned to service on April 21, 1989.

Extensive problems were encountered while attempting to return RM-063H to service, and subsequently RM-063H has not been returned to service. The J followhg components required replacement'or repairs: i

1. 'Repir.ced rotary selector switch on ratemeter.

2. Replaced detector (significant lead time item).

3. Repaired pre-acp. (

4. Replaced log ratemeter. .j

5. Replaced log ratemeter circuit board. 1

6. Replaced meter potentiometer. l

7. Replaced Action Pak #3 for bulk flow. j

8. Repaired high noise problem on Action Pak #5 for bulk flow.

9 .' Found defective Dahl controller "B" for sample flow.

On Mey 8, 1989, RM-063L, RM-063M, and RM-063H were removed from service'for calibration of the flow control circuit under EP-063F. Problems with the Dahl controller prevented returning the three monitors to service 'within the'seven '

' day LCO. ThI controller would not provide the proper signal to automatically control the sample flow through the N and H detectors and filters. The manufacturer no longer makes, repairs, or carries spara payts for this model controller. Repairs will be attempted on 5:1te. If repair is not possible, a new style controller (usual delivery time of~ E-10 ~ weeks) will be ;ubstituted as a modification to the monitor. Following the controller repair or Replacement, monitors RM-063L, RM-063M, and RM-063R will be returned to operability. This should be completod by September 1, 1989.

If you have any questions, please contact us.

Sincerely, i

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,[

K. . Morris Division Manager Nuclear Operations

]

KJM/ tem l

1 cc: Leboeuf, Lamb, Leiby & Macrae 1 R. D. Martin, NRC Regional Administrator  ;

P. B. Milano, r4RC Project Manager 1 P. ti. Harrell, NRC Senior Resident inspector 4

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