ML20084L874

Ao:On 740528,during Analysis of Waste Sample Tank A,High beta-gamma Radioactivity Concentration Determined.Condition Was Not Brought Into Compliance within 24 H.Caused by Damaged Filter Septa.Water Transferred to C Tank

ML20084L874
Person / Time
Site:	Dresden
Issue date:	06/06/1974
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084L877	List: ML20084L874 ML20084L878 ML20084L881
References
408-74, NUDOCS 8305240134
Download: ML20084L874 (3)

Text

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C mme .:lth Edison (i ppM) One Fast nal Fina. Chicago, llbt'ais (j'

. i V/// Address Reply to: Post O'hce Box 767 Chicago, Uhnois 60690 BBS Ltr.#408-74 Dresden Nuclear Power Station R. R. 01 Morris, Illinois 60450 C) ^-

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Hr. J. F. O' Leary, Director 50-?.37 'd ' ">.'rAb '

Directorate of Licensing -

U. S. Atomic Energy Commission \

Washington, D. C. 20545 \

SUBJECT:

LTCCNSE DpR-19, D7ESDEN NUCLEAR PO'4ER STATION, UNIT #2, REPORT CF ATCOPlfAL OCCURRF.NCE PER SZCTION 6.6.3.1.a CF THE TECHNICAL SPECIFICATIONS.

2/3 RAD'1ASTS ABOVE GROUND STORAGE > 0.7 Ci FOR LONGER THAN 24 HOURS.

References:

1) Notification of Region III of AEC Regulatory Operations Telephone: Mr. Fisher, 1610 hours0.0186 days <br />0.447 hours <br />0.00266 weeks <br />6.12605e-4 months <br /> on May 29, 1974.

Telegram: Mr. J. Keppler,1715 hours0.0198 days <br />0.476 hours <br />0.00284 weeks <br />6.525575e-4 months <br /> on May 29, 1974.

Dear Mr. O' Leary:

Thie letter le to report ennditien relating to the eperatien of Unit 2/3 Radwaste at about 1504 hours0.0174 days <br />0.418 hours <br />0.00249 weeks <br />5.72272e-4 months <br /> on May 28, 1974. At this time, the "A" Waste Sctple Tank uas filled with water to a icvel of 857.. A subsequent analysis determined a beta-gamma radioactivity concentration t. ,

of 1.3 x 107 picoeuries per liter which resulted in an above ground curie content in the tank of 1.0 curie. This condition was not brought into cot::pliance within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and therefore was contrary to Section 3.8.D of the Technical Specifications. The "A" WST radioactivity was reduced to Icss than 0.7 curica by transferring water to the above ground Waste Surge Tank. This action raised the tank level to 817. capacity and resulted in a beta-gaen:a radicactivity content of I curie in the surEe tank. This condition was not brought into Technical Specifications ccmpliance within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

Units 1 and 3 were down for refucting outages.

PROBLEM The Unit 2/3 Radwaste Uaste Collector Filters had damaged filter neptums, and repair of the filtera was still in progress at the tire of the occurrcnce. In addition, there was no dcmineralizer available at the time the vaste collector was processed to "A" WST. The resultant water quality did not nect station requircaents for transfer to condensate storage.

The normal procedure in this situation would be to reprocess the "A" W3T

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- ,' Mr. J., F. O'Le ry Juns 6, 1974 to the waste collector, through a filter, and the new demineralizer(installed May 28). Ilowever, this was not possible because the waste collector was already full.

Due to filter problems, water could not be processed at normal rates and unprocesced water accumulated in the waste collector. In addition to the filter repairs in process, the turbidity and crud level of the unprocessed water was unusually high, causing short filter runs and a large number of filter backwashes. Mechanical problems in the filter backwash system caused further delays in the transfer of water from the waste collector.

Due to the high crud level and the high number of filter backusshes, the "A" cicanup sludge tank overflowed onto the 2/3 Radwaste basement floor. Further reprocessing of the "A" WST to the waste collector through a filter and domin-eralizer would have resulted in damage to equipment in the Redwaste basement from the continued overflow of the cleanup sludge tank and possible overflow of the waste collector itself.

"A" WST was finally transferred to the waste surge tank to prevent flood damage to the essential equipment in the basement. By 1610 hours0.0186 days <br />0.447 hours <br />0.00266 weeks <br />6.12605e-4 months <br /> on Iby 28,1974, the "A" UST had been emptied.

Due to the filtering conditions and resultant flooding described above, the waste curge tank was not brought into cempliance until OS15 hours on June 3, 1974. At this time the surge tank level was 63%, the beta-ganna radioactivity was 3.4 x 106 picoeuries per liter, resulting in a tctal e..-<n en,en-, n+ n u e...<-n . ..<>u<- vn-u <--> c--nece... <--- ><-<>- vu-water in the waste surge tank was reprocessed to "C" WST.

INVESTICATION The causes of the occurrence are as follows:

1. The inability of the Waste Collector Filters to properly filter water due to damaged filter septums caused flooding in the Radwaste basement.

2. High turbidity and crud in water to be processed caused high number of filter backwashes. Mechanical problems occurred on backwash system.

3. Due to the inability of the waste collector filters to properly filter water, the ".A" UST and waste surr,c tank could not be processed to a below ground tank within 24 hcurs.

4. The above ground tanks contained 0.7 curies for greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to prevent further flooding of the radwaste basement and extensive damage to equipment necessary for processing radwaste water.

L

w Mr. .J.

F. 0%m/

o O June 6, 1974 CORRECTIVE ACTION The insnediatsi actica was to start the transfer of water frora "A" WST to the waste surge tank, which uas then processed to "C" WST. By the end of these operations, all tanks were brought into compliance with the Technical Specificaticus. Modification of the waste collector filters to provide greater reliability and better perforcance are in progress. The water which flooded the radwaste basement is being pumped to the floor drain collector.

EVALUATIONS The presence of I curie beta-gamma radioactivity in either the "A" waste sanple tank or the waste surge tank did not present a hazard to the public since this water was not released to the river. Had a failure of the vaste surge tank occurred, as described in ~ Amendment i?9,Section V.C.1 of the S. A.R. , and the radioactivity contained in the tank been released to the aquatic environment, the limits as specified in 10 CFR 20.106 would not have been approached when averaged over one year.

The Dresden Technical Specifications have recently been revised on Unit 1 to allow 90 curies in all above ground tanks. In addition, the company plans to submit a request for a similar limit on Unit 2 and 3.

A review of the deviation and incident reports for 1973 and 1974 indicated that, although there were infrequent occasions when the chove

.grcund tr.nka cxecedad 0.7 carica, the station rcprccesscd the water within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

We believe that the corrective actions taken to bring the condi-tion into compliance with Technical Specifications were appropriate considering the attempt to bring the ccndition within Technical Specification requiret:ents in the shortest period of time. Also, the modification of the vaste collector filters to provide greater capacity and better performance should minimize the potential for future incidents of this nature.

Sincerely ( /

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• B.~B. Stephenson Superintendent -

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