ML20084L818

Ao:On 740620,floor Drain Sample Bank Discharged to Discharge Canal at Rate Which Resulted in Excessive Radioactivity. Caused by Failure to Follow Operating Order.Discharge Reduced

ML20084L818
Person / Time
Site:	Dresden
Issue date:	06/27/1974
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084L820	List: ML20084L818 ML20084L822 ML20084L830
References
467-74, NUDOCS 8305230740
Download: ML20084L818 (2)

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,/, Address Reply to: Post Othcc Box 767 g.N*y Chicago. Ilknois 60C90 BBS Ltr.0467-74 Dresden Nuclear Power Station

- R. R. #1 Horris, Illinois 60450 June 27, 1974 o p 4

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Mr. J. F. O' Leary, Director )' . ;; .t ;: ;f Directorate of Licensing O.. . i-U. S. Atomic Energy Commission Washington, D. C. 20545 k *"

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SUBJECT:

_ LICENSE DPR-19. DRESDEN NUCLEAR POWER STATION. UNIT #2, REPOR_T OF EXCEEDU:G lx10-/ uC1/ml IN CONDENSER COOLING WATER DISCHARGE

_ CANAL PER SECTION 3.8.C.2 OF THE TEC'fMICAL SPECIFICATIONS.

_2/3 RADWASTE DISCHARGE 1.0x10-i uCi/ml.

Roferences: Notification of Region III of AEC Regulatory Operations Telephone: F. luura, 1325 hours0.0153 days <br />0.368 hours <br />0.00219 weeks <br />5.041625e-4 months <br /> on June 21, 1974 Telegram: J. Keppler, 1430 hours0.0166 days <br />0.397 hours <br />0.00236 weeks <br />5.44115e-4 months <br /> on June 21, 1974

Dear Hr. 0' Leary:

This letter is to report a conditi:r. relatinn to tha c= ratien cf ur.i:. 2/3 rad.e iu et u'ou L G700 huuto un_ June 2G, 1974. At this time, the "A" floor drain sample tank ("A" FDST) was discharged to the D2/3 discharge canal at a rato which resulted in an apparent B-T radioactivity of 1.02 x 10-7 uCi/ml in the discharge canal. The radioactivity limit specified for the discharge canal (on an unidentified basis) is 1x10-7 uC1/mi above background (section 3.8.C.2).

PROBLEM -

At the time of the occurrence, Unit 2 was in run mode at 2131

, IMt. The D2/3 radwaste basement was flooded and in an effort to procecs as much water as possible out of the "A" FDST, the factor used in calcula-ting the discharge of liquid effluents was increased to 10 without proper i authorization. The operating order permits a maximum factor of 3 without authorization.

l Itad the diccharge rate been exactly 5.6 gpm as calculated using l the factor of 10, the radioactivity in the discharge canal would not have I exceeded 1x10-7 uCi/ml. However, the actual discharge rate was 5.7 spm which resulted in an apparent beta-gats.a radioactivity of 1.02x10-7 uC1/ml in the discharge canal.

At 1700 hours0.0197 days <br />0.472 hours <br />0.00281 weeks <br />6.4685e-4 months <br /> on June 20, 1.974, the discharge rate was reduced to 4.4 spm, bringing the activity within Tecli. Spec, limits for die, charge on an unidentified ' basis.

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Hr. J. F. O' Leary O O Juna 27, 19/4 INVESTICATION It was determined that the following events led to the occurrence.

1) Failure to follow the operating order which specifies the factor to be used to calculate discharge rates.

2) The actual discharge rate was 5.7 spm which was slightly above the planned rate of 5.6 gpm, although a two-hour check on tank level indicated a discharge rate of 5.5 gpm at 0900, June 20, 1974.

The original calculation of the radioactivity of 1.02x10-7 uCi/ml in the D2/3 discharge canal was conservative since it was calculated using the dilution flow from the routine discharge card. The dilution flow printed on the discharge card is 69% of the actual discharge flow. Thus, when the actual dilution flow is used, the activity in the discharge canal is calculated to be 0.91x10-7 uCi/ml. Therefore, the Technical Specifications limit of lx10-7 uCi/ml for liquid effluent discharge on an unidentified basis was not exceeded.

CORRECTIVE ACTIONS The hmediate corrective action taken when tha problem was dis-eevered "?e te reduce the dieah?.rge rete te ':.^ gp- .

In order te prevent a future occurrence of the type described in this letter, the operating order was reviewed with the shif t supervisors, emphasizing the correct use of multiplying factors to be used in calcula-ting D2/3 discharge rates and the approvals required to exceed a factor of 3 on the river discharge cards.

EVALUATION The radioactivity in the discharge canal was recalculated using the actual dilution flow and the corrected radioactivity in the canal was 0.91 x 10-7 uCi/ml; therefore, the Technical Specification limit of 1 x10-7 uCi/ml for liquid effluent discharge on an unidentified basis was not execeded.

Since the Technical Specifications limit was not exceeded, the discharge did not present a safety hazard to the public or environment.

Sincerely,. O if -,

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B."B. Stephenson Superintendent BBS:IJ:N:do f

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