ML20214H263

Informs of Plans to Test Emergency Condenser Tube Bundle for Leakage During June 1987 Outage.Extent of Analyses Planned Discussed

ML20214H263
Person / Time
Site:	Big Rock Point File:Consumers Energy icon.png
Issue date:	05/19/1987
From:	Johnson B CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
NUDOCS 8705270329
Download: ML20214H263 (2)

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p 4 Consumers

@meestauus Power AIN MISsAE55 General offices: 1946 West Pernell Road,Jacksort, MI 49201 + (517) 788-0550 L

May 19, 1987-Nuclear Reg'ulatory Commission Document Control Desk .

Washington,- DC 20555 DOCKET 50-155 - LICENSE DPR BIG ROCK FOINT PLANT.-.  !

SUSPECTED EMERGEhCY CONDENSER TUBE LEAKAGE During Operating Cycle 20, No. 2 emergency condenser tube bundle developed an apparent minor leak as indicated by xenon analyses'of secondary side. water.

At that time, June-1985, a decision was made to isolate the No. 2 tube bundle.

Investigation of the source of leakage was performed during the:1985 refueling

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outage. The results of the leakage investigation were submitted to the NRC in-our letter dated October 31, 1985. The four leakage examinations conducted-did not identify a source of the leakage and as a result we initiated an.

increased frequency xenon sampling program to verify leak tight' integrity. .

This weekly sampling program commenced with startup from the refueling outage ~

in November 1985. In early 1986 a weekly tritium sampling' program.was . . ,

implemented in addition to the xenon sampling program. 'After approximately H three months of tritium sampling, the tritium concentration appeared to be ,

leveling off, apparently indicating that a leak was not present. Even though '

the sampling programs did not indicate leakage,-the sampling programs were.

continued.

Tritium sampling was initiated because xenon'is not a good: indicator or tracer for detecting or quantifying leakage from the' emergency condenser _for several! ,

reasons (short half life, solubilities, uncertain mixing, etc).- Upon subsequent plant startups, we have seen xenon for short periods of time in.  ;

shell side condenser samples, then it disappears. This phenomenon is yet.. H unexplained, but it would indicate that the xenon levels would have gone-down ~

even if we had not isolated.the No. 2 tube bundle in June,'1985.-

Review of the tritium analyses data for the latter part of 1986~ indicates an-apparent small. leak in the emergency condenser-(approximately 1.0 liter / day).

However..there are uncertainties involved in'this data also.. The cooling

. water to the emergency condenser is demineralized. water, tritium could be entering via'this pathway if a valve is leaking since this cooling water l

'has tritium in it. Tritium analyses since the 1987lstartup indicate j approximately the same levels as were present prior to shutdown.

OC0587-0068-NLO4 8705270329 870519-ADOCK 0500 5 N j hDR a y

v Nuclear Regulatory Commission 2 Big Rock Point Plant Suspected Emergency Condenser Tube Leakage May 19, 1987 The 1986 tritium data was reviewed by Lauren Hueter of the Nuclear Regulatory Commission, Region III during his inspection on March 3 and 4,1987. He

, suggested we attempt to quantify the suspected leak and add it to the radioactive' semiannual effluent report. We have initiated the process of adding the data to the report. However, due to the small amount (approximately .0002 gpm) and the uncertainties associated with the data, it is felt inappropriate to account for this apparent leakage in the daily unidentified primary system leak rate calculation.

Concerns have been raised since then about whether or not operating the plant 7

with a small leak in the emergency condenser is a degraded condition. To resolve these concerns, Plant Management has decided to test the No. I emergency condenser tube bundle for leakage during the upcoming June 1987 outage. Helium leak testing will be used to conduct the test. (Condenser tubes will be pressurized with helium and observed for bubbles to indicate leakage.)

If a leak is detected, the leaking tube (s) will be plugged. If a leak is not detected, the conclusion will be that a leak does not exist since it cannot be detected by state-of-the-art methods. Gamma isotopic for xenon and tritium analyses will be performed in either event for a period of at least one month (once per week) after startup to verify no leakage or that levels have not increased above past analyses. Unless an increase in radioactivity levels is found, sampling and analysis will revert to a monthly basis (gamma isotopic only)'which is the same as prior to June 1985. If an increase in radioactivity occurs, it will be addressed at that time.

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Further, analyses for xenon will be performed approximately one week af ter startups from cold shutdown since past analyses have shown this to be the optimum time for xenon detection should leakage occur.

C m e pr:u - &___/

Brian D Johnson Staff Licensing Engineer I

CC Administrator, Region III, NRC NRC Resident Inspector - Eig Rock Point

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