ML19347C817

Ao:On 730914,leakage Occurred from Reactor Bldg Closed Cooling Water Sys to Discharge Canal Via Svc Water Sys. Caused by Leaking Tubes in Reactor Bldg Closed Cooling Water Heat Exchanger 1-2.Investigation Continuing

ML19347C817
Person / Time
Site:	Oyster Creek
Issue date:	11/08/1973
From:	Ross D JERSEY CENTRAL POWER & LIGHT CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 8103040852
Download: ML19347C817 (3)

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Jersey Central Power & Light Company b'$ ~

MADISON AVENUE AT PUNCH BOWL ROAD e MORRISTOWN. N.J.079SO

• 201-539-6111 menn or tu General g.]. e] Public Utilities Corporation -

sinn e November 8, 1973 N '} 8 e, #

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>e fr s I t i l\ s- o Mr. A. Giambusso ~

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Deputy Director for Reactor Projects 3 Directorate of Licensing -

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f 'ficq J United States Atomic Energy Commission 6 4d , k "e< [i 7 Washington, D. C. 20545 i'%' A  ?

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Dear Mr. Giambusso:

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Subject:

Oyster Creek Station Docket No. 50-219 Closed Cooling Water System Leakage This letter serves to report an umaonitored release due to leakage from the reactor building closed cooling water system to the discharge canal via the service water system. This event is considered to be an abnormal occurrence as defined in the Technical Specifications, paragraph 1.15C.

Notification of this event, as required by the Technical Specifications, paragraph 6.6.2.a, was made to AEC Region I, Directorate of Regulatory Oper-ations, by telephone on Tuesday, October 30, 1973 and by telecopier on Wednesday, October 31, 1973.

On September 14, 1973, leakage into the reactor building closed cooling water system from a leak in the fuel pool cooling system was identified and isolated. As a result, the closed cooling water system activity was analyzed on several occasions with the highest concentration calculated to be 1.9x10-4 pCi/ml in a sample taken on September 26, 1973. The activity was identified to be primarily Cs 34 and Csl37 l

On October 19, 1973, leakage from the closed cooling water system was noted as indicated by a decreasing level in the reactor building closed cooling water system surge tank of up to 4,-4.5"/hr. (<1.0 gpm) .

The cause of the release was a tube leak in the #1-2 reactor building closed cooling water heat exchanger.

Operations personnel began isolating various components of the closed cooling water system in order to identify the source of leakage. As noted above, the rate of leakage /,- the system was conservatively estimated to be 1.0 gpm. On October 22, 10 '

a sample of the closed cooling water system 9/030'/DM "'

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Mr. Giam^busso November 8, 1973 indicated a concentration of 6.3x10-5 pCi/ml, indicating that leakage- had oc-curred during the period of September 26, 1973 through October 22, 1973. On i 0ctober 29, 1973, RBCCW heat exchanger #1-2 was identified as the source of leakage. Prior to this date, it was not recognized that the leakage was:to

- the environment. A closed cooling water sample taken on October 30, 1973, following repairs to the. heat exchanger, indicates the present activity IcVel to be 2.5x10 5 pCi/ml. ,

Consideration was given to sampling the service' water discharge for l

radioactive concentrations during the early stages of investigation into the source of leakage. Due to the low activity levels present in the closed J cooling water system, the added dilution factor cf 6000:1 would have made the activity levels in the service water system below detectable limits.

. The release was evaluated usin and the maximum concentration of 1.1x10pCi/ml g a leak rate Csl37 and of0.8x10-4 one gallon per minutepCi/ml Cs l

Using a discharge canal flow of 4.5x10 Spm and the appropriate recirculation 5

factor of 3.76, the maximum concentration and permissible concentrations in the discharge canal at the site boundary due to the RBCCW 1eakage were:

Allowable MPC

, Isotope Canal Concentration (With Recirculation)* t of MPC Csl37 2.4x10-10 pCi/mi 5.4x10-6 pCi/ml 0.0044%

Cs134 1.74x10-20 pCi/ml 2.4x10-6 pCi/ml 0.0073*.

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• Based on Appendix B, Table II, Column 2, of 10CFR20, and reduced by the j appropriate recirculation factor.

i The release rate was, therefore, well within license limits and did not threaten the health or safety of the public.

l l A total of 14,500 gallons of water was estimated to have been released ~

over a ten-day period. During this period, only four releases were made into the. discharge ocanal from the station. These totaled 6,300 gallons and were all releases from the laundry drain tank. The releases were made on an unidentified l bases 'resulting in a discharge canal concentration ranging from 3.3x10-9 to 7.8x10-10 pCi/ml over an accumulative time period of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

1 To prevent a repetition of this occurrence, the station operating staff

is determining the best technique for removing the activity from the RBCCW system.

This will niost likely be a temporary demineralizer flow path in the system.

Further, the appropriate procedures will be revised to require in the future, prompt action to identify the location of a system leak plus sampling and analysis of both the closed cooling and service water flow streams for detectable j activity.

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-Mr. Giambusso -

3- November 8, 1973 i

Enclosed are forty (40) copies of this report. -

Very truly yours,

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,? h as-l Donald A. Ross Manager, Nuclear Generating Stations DAR:cs ,

Enclosures

.; cc: Mr. J. P. O'Reilly, Director . -

Directorate of Regulatory Operations, Region I I

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