ML20084K411

AO 50-237/1974-49:on 740926,radioactivity in a Floor Drain Sample Tank Found Higher than Limit.Caused by Inability of Floor Drain Sys to Process Vol of Water Entering Sys.Max Recycle Radwaste Sys Under Const

ML20084K411
Person / Time
Site:	Dresden
Issue date:	10/08/1974
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20084K414	List: ML20084K411 ML20084K416
References
731-74, NUDOCS 8305190386
Download: ML20084K411 (3)

Text

r 4 1 _, C mm Jalth Edison [s 0 f) [ gan, . One First !.... anal Ptna. Ch.cago. Illinois C \//,J Address Rep;y to: Post Office Box 767 Y Chicago, litincis G0690 w

BBS Ltr.#731-74 Dresden Nuclear Power Station R. R. il Morris, Illinois -

October 8, 1974 60450.$15f/

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'Mr. Jr.mes G. Keppler, Regional Director '0CT1 ~ 1974> E, Directorato of Regulatory Operations-Region III CJ U L IIG,{3 61, U. S. Atomic Energy Co r ission , dj$rs /

799 Roosevelt Road t'a 2M! -

c4 Glen Ellyn, Illinois 60137

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SUBJECT:

REPORT O? AP2:03 MAL OCCURRENCE PER SECTION 6.6. A 0F THE TECHNICAL

,SJECIFICATICNS. -

GREATER TPldi 0.7 CITdIE IN ABOVE GROUND STORAGE TANK FOR PERIOD IDNGER THA'i 24 HOITRS.

References:

1) Regulatory Guide 1.16 Rev.1 Appendix A

2) Notification of Region III of AEC Regulatory Operations Telephone Mr. C. Brown, 1030 hours0.0119 days <br />0.286 hours <br />0.0017 weeks <br />3.91915e-4 months <br /> on October 3, 1974 Telegram: Mr. J. Keppler, 1245 hours0.0144 days <br />0.346 hours <br />0.00206 weeks <br />4.737225e-4 months <br /> on October 3, 1974 Report Number: 50-237/1974-49 Report Date:. October 8, 1974 Occurrence Date: September 26, 1974 Facility: Dresden Nuclear Power Station, Morris, Illinoic IDDTPIPICATION OP OCCURRIDICE This lotter addrescos the storage.of liquid radioactive wasto in "A" Floor Drain Sample Tank (an above ground tank) in quantities greater than 0 7 Curie for a period longer than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

CONDITIONS FRIOR TO OCCURREr' ICE Prior to and during the coeurrence, Dresden Units 2&3 were in cold chutdown.

No testing of the unite was in progress.

DESCRIPTION OF OCCURRDICE On 9/25/74 at 0110-hours, the Unit 2/3 Radanste Floor Drain Collector Tank '

was processed by the radwacto operator thru the floor drain filter to "A" floor drain cample. tank ("A"FDGT). Trannfer of liquid to "A"FDST was ,.

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' O r. Jamen G. Keppler October 8, 1974 complete by 0155 houra on 9/25/74. At a level of 58% "A"FDST was placed on recirculation at 0425 hours0.00492 days <br />0.118 hours <br />7.027116e-4 weeks <br />1.617125e-4 months <br /> on 9/25/74 for campling and analycic. Sampling by the radiation protection department took place at 0600 hours0.00694 days <br />0.167 hours <br />9.920635e-4 weeks <br />2.283e-4 months <br /> on 9/25/74.

Subacquent lab analysis indicated a grosa radioactivity in "A"FDST of 192x 107 pCi/1. This combination of radioactivity and tank volume placed the total radioactivity in "A"FDST at 0.94 Curic. Due to limited underground tank ctorage capacity, "A"FDST was diccharged on a controlled bacio to the river at 2.25 GFM beginninr; at 0910 hours0.0105 days <br />0.253 hours <br />0.0015 weeks <br />3.46255e-4 months <br /> on 9/25/74. Thic controlled dis-charge on an unidentified radienuclide basis added 50.4 pico curica per liter to the dischart;e canal. This incidtnt uas clacsified an a station deviation at 0800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br /> on 9/26/74 at which time the level in "A"FDST was 425 and belcw 0.7 Curie, thus terminating the abnarml occurrence. "A"FDST was alloucd to continue discharging, finiching at 1800 hours0.0208 days <br />0.5 hours <br />0.00298 weeks <br />6.849e-4 months <br /> on 9/27/74. Further investira-tion revealed that the activity content in "A"FDST was f 0.7 Curie for approx-imately 30 houro. This incident was reclacaified as an abnormal occurrence at 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> on 10/2/74 DESIG'iTION OF ATPfliF2:P CAUSP OF OCCURRU!CE (Design Deficiency)

The single cause of the occurrence was the inability of the floor drain system to process the volume of water cntering the system. Uater in the floor drain col)ector tank was processed to the floor drain sample tank to mke room for inconing water. There was no roca in eithcr the uacto collector or "A" or "B" war.ta neutralizer tanks (tc:durgrotmd bnks) to proceca the water frca "A"FDST.

"A' 5Ef was allcued to cmpty to the river at a controlled rato of discharge.

Contributini; to the o' cove cauce was the failure to obtain an analycis of cross activity in the floor drain collector tank prior to procecains water to above ground storage. This action was nece. vary due to the inability of the floor drain cyotea to process the volume of water entering the cystem.

AUlHS1S OF OCCURE:CE The precence cf 0 94 Curies of radioactivity in "A" floor drain cample tank did not present a hazard to the public. Had a rupture of the tank occurred and the radioactivity contained in the cemple tank been relcaced to the aquatic enviro =ent, the limita of 10 CFR 20.106, for relcaae of liquida containing radioactive caterial to unrestricted areas when averaged over one year, vould not h2ve been approached. Also, the controlled diccharge of "A"FDST did not present a hazard to the public since this discharge was only 50.4 percent of the Technical Specification limit for liquid discharges on an unidentified radionuclide bacio.

1 CORRFfTIVE ACTION We believe the corrective action t4tken to bring the condition into compliance with Technical Specifications in the shortest poscible time was appropricto considering the limited tank volurre available in Raduaste.

, s Mr. James G. Keppler N, lober 8, 1974 , , , , ,

Two major corrective actions are in progress at this time. The maximum recycle radwaste system which will provide additional means to treating liquid radioactive waste iu under construction. Also, the Drecden Unit 1 Technical Specificaticna allow 90 curies in all above ground liquid storage tanks. This Unit 1 Tecimical Specification limit in being revieued for applicability to the Unit 2 and 3 Technical Specifications.

Sincerely, f}l. s e n/f, B. B. Stephenson Superintendent BBS:GWB:do