ML20084L818
| 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: |
| References | |
| 467-74, NUDOCS 8305230740 | |
| Download: ML20084L818 (2) | |
Text
,g, C::mmehrith Ediscn O
' pm one first..senat Plaza. Cheago, illenois
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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 o p 4
June 27, 1974 50-237 b
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Mr. J. F. O' Leary, Director
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. i-U. S. Atomic Energy Commission 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 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,.
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B."B. Stephenson Superintendent BBS:IJ:N:do f
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