ML20135B206

NPDES Noncompliance Notification:On 961116,small Leak of Water Was Discovered at B Radiation Waste Test Tank & Discharged Into Catch Basin.Tank Contained Boric Acid at Time of Incident.Calculation Has Been Performed Re Acid

ML20135B206
Person / Time
Site:	Millstone
Issue date:	11/22/1996
From:	Scace S NORTHEAST NUCLEAR ENERGY CO.
To:	Grier J CONNECTICUT, STATE OF
References
D10531, SES-96-GN-049, SES-96-GN-49, NUDOCS 9612040204
Download: ML20135B206 (2)

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<hfjg/ 8 Utilities System s ,, t. taiiie. smw comp.oy P.O. Box 270 ifartford CT 061410270 (860) 665-5000 November 22,1996 SES-96-GN-049 D10531 Mr. James Grier Principal Sanitary Engineer Bureau of Water Management Permitting, Enforcement, and Remediation Division Department of Environmental Protection 79 Elm Street .

Hartford, CT 06106

Dear Mr. Grier:

Millstone Nuclear Power Station NPDES Permit No. CT 0003263 Release of"B" Radiation Waste Test Tank Liauid to DSN 006 The following report provides information on an event reported to you by phone on Tuesday, November 19,1996.

At approximately 4:30 p.m. on Saturday, November 16,1996, a Unit 3 Operator discovered a small leak of water, apparently originating form the "B" Radiation Waste Test Tank and discharging into a catch basin. The leak was immediately secured and Unit 3 Chemistry was notified. Samples of water in the catch basin receiving the leakage and in other downstream catch basins, including the NPDES sample point for DSN 006, were subsequently ecliected and analyzed. Radioactivity was detected in the first catch basin and its contents were collected in a drum and handled as radwaste. Additional sample results, downstream of the first catch basin, indicated no detectable radioactivity. The source of the leak was an instrumentation line fitting that had come loose.

The "B" Radiation Waste Test Tank at the time of the incident contained boric acid at 2,020 mg/1. Boric Acid was detected in downstream catch basins and in the NPDES sample point for DSN 006. A maximum boric acid concentration of 24.6 mg/l was found at 5:10 p.m. on November 16,1996.

The "B" Radiation Waste ' %st Tank was about 10% full at the time and contained low levels of radioactivity. There was no change in the tank level during the period when the leak occurred.

040058 (M422 RR SM 9612040204 961122 ADOCK 05000423

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, Mr. James Grier D10531/Page 2 i November 22,1996  !

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l A calculation was performed to determine the maximum amount of boric acid that could have  !

been released. Because "B" Radiation Waste Test Tank level indication did not change, the first ]

measurable indication (1% or 210 gallons) was chosen as a default value. This conservative ,

calculation resulted in an estimate of 1.6 kg of boric acid released during the event. DSN 006 has a boric acid permit limitation of 4.1 kg/ day.

This event was not reportable under NRC Reportability criteria because no detectable activity was released offsite.

Should you have any questions, please call Mr. Paul Jacobson, Northeast Nuclear Energy Company, at (860) 665-3617.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY C tLct.-

S. Encace /

Director of Nuclear Engineering Programs S cc: Ms. Michelle Dincia Bureau of Water Management Department of Environmental Protection 79 Elm Street Hartford, CT 06106-5127 Mr. Michael Harder Bureau of Water Management Department of Environmental Protection 79 Elm Street Hartford, CT 06106-5127 NRC Document Desk

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