ML20206L823

Special Rept 88-18:on 881025 & 26,failure to Maintain Specific Activity of Primary Sys within Administrative Limits Occurred.Alternate Letdown Sys Purification Demineralizer Placed in Svc

ML20206L823
Person / Time
Site:	Rancho Seco
Issue date:	11/23/1988
From:	Keuter D SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:	Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
88-18, AGM-NPP-88-601, GL-85-02, GL-85-2, NUDOCS 8811300256
Download: ML20206L823 (5)

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SACRt.MENTo MUNICIPAL UT)dTY DISTRICT C 6201 S Street. P.o. Box 15830. Sacramento CA 958521830.(916) 452 3211 AN ELECTRIC SYSTEM SERVING THE HEART OF CALIFORNIA AGM/NPP 88 601 N0Y 2 31988 U.S. Nuclear Regulatcry Co.amission Attn: J. B. Martin, Regional Administrator Region V 1450 Maria Lane, Suite 210 Halnut Creek, CA 94596 Docket No. 50-312 Rancho Seco Nuclear Generating Station License No. DPR-54 SPECIAL REPORT NUMBER 88-18: FAILURE TO MAINYAIN SPECIFIC ACTIVITY OF THE PRIMARY SYSTEM HITHIN ADMINISTRATIVE LIMITS

Dear Mr. Hartin:

The specific activity of the primary tystem exceedsd administrative limits specified in Rancho Seco Administrative Procedure RSAP-0222 and as committed to in our response to Generic Letter 85-02. The bacr&miento Municipal Utility District hereby submi c Special Report No. 38-18 in accordance with Rancho Seco administrative controls.

Members of your staff with questions requiring additional information or clarification may contact Mr. r icr Yochheim at (209) 333-2935, extension 4378.

Sincerely, C- m i

- -% v Dan R. Keuter A;51stant General Manager Nuclear Power Production Attachment cc w/atch: . D'Angelo, NRC, Rancho Seco Document Control Desk, Washington DC

$k OObbk RANCHO SECO NUCLEAR GENERATING STATION D 1444o Twin Cities Road. Herald, CA 95638 9799.(209) 333 2935

.. 1 SPECIAL REPORT NUM8ER 88-18 ,

Failure to Flintain Specific Activity of the l Primary Sy: tem Hithin Administrative Limits 1 Date of Occurrence Oct'ober 25-26,'1988 Plant Conditions at Time of Occurrence Due to a Technical Specification requirement, the Control Room Operators ,

began a controlled shutdown of the plant on October 25 at 0402 hours0.00465 days <br />0.112 hours <br />6.646825e-4 weeks <br />1.52961e-4 months <br />.

The plant reached hot shutdown conditions at 0843 hours0.00976 days <br />0.234 hours <br />0.00139 weeks <br />3.207615e-4 months <br />. The react r remained in hot shutdown untti restart on October 29.

Identification of Occurrence The specific activity of the primary system exceeded administrative ,

limits specified in Rancho Seco Administrative Procedure RSAP-0222 Rancho Seco Chemistry Control Commitment. The procedure requires the submission of a Special Report if the specific activity of the primary coolant is either greater than 0.8 pCi/ml I-131 or 43/E pCi/ml.

Descriotion of Occurrence -

For the period from approximately 1305 hours0.0151 days <br />0.363 hours <br />0.00216 weeks <br />4.965525e-4 months <br /> on October 25 to 1727 hours0.02 days <br />0.48 hours <br />0.00286 weeks <br />6.571235e-4 months <br /> on October 26, while in a hot shutdown condition, Reactor Coolant System

, sample data indicated that specific activity was above 0.8 pCi/ml .

I-131; the 43/E limit was not exceeded. It is normal for Iodine activity '

to increase for a short period of time after a power reduction. The District had committed to the 0.8 pCi/mi I-131 limit via letter dated June 11, 1985, in response to Generic Letter 85-02.

Corrective Action Taken In accordance with RSAP-0222, on detection of the unusual condition, '

isotopic analysis continued until restoration of specific activity to within limits. Control Room Operators placed the alternate Letdown System purification demineralizer in service at 1028 hours0.0119 days <br />0.286 hours <br />0.0017 weeks <br />3.91154e-4 months <br /> on ,

October 26. The analysis performed on October 26 at 1727 hours0.02 days <br />0.48 hours <br />0.00286 weeks <br />6.571235e-4 months <br /> -

indicated that specific activity was below 0.8 pC1/ml I-131.  ;

Per RSAP-0222 the following information is enclosed: {

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• Primary coolant specific activity and time duration when the activity exceeded 0.8 pC1/ml I-131 (Attachment 1).

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• Reactor power history starting 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> prior to the first samp . in which the limit was exceeded (Attachment 1).

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• Cleanup flow history starting 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> prior to the first samale in  !

which the limit was exceeded (Attachment 2).  !

• History of degassing operations, if any, starting 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> , to '

l the first sample in which the limit was exceeded. (No data -

enclosed for this item because degassing o;,erations were not performed t during the period I-131 specific activity exceeded the limit.)  ;

• Fu91 burnup by core region (Attachment 3).

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SPECIAL REPORT 88-18 Attachment 1 .

Failure to Maintain Specific Activity of the Primary System Within Administrative Limits P0HER '

LEVEL PARAMETER DATE/ TIME (% Full Paul VALUE I-131 22-Oct-88 02*.00 92.0 7.81E-2 pC1/ml 23-Oct-88 00:15 92.0 9.62E-2 pCl/ml 24-Oct-88 00:20 93.0 8.92E-2 pCi/mi 25-Oct-88 07:20 12.0 2.30E-1 pC1/mi 25-Oct-88 09:00 0.0 3.91E-1 pC1/mi 25-Oct-88 13:05 0.0 9.9E-1 pCi/ml*

25-Oct-88 14:10 0.0 9.35E-1 pC1/m1' 25-Oct-88 16:10 0.0 9.33E-1 pC1/m1' 25-Oct-88 18:10 0.0 1.090 pC1/m1' j 25-Oct-88 22:00 0.0 1.1 pC1/m1' I 26-Oct-88 02:00 0.0 1.04 pCi/m1' 26-Oct-88 06:00 0.0 9.62E-l pC1/mi' '

26-Oct-98 10:40 0.0 9.57E-1 pC1/m12*

26-Oct-88 17:27 0.0 6.9E-1 pC1/ml i

• Indicates an administrative limit has been exceeded

• • Alternate Letdown System purification demineralizer placed in service l at 1028 hours0.0119 days <br />0.286 hours <br />0.0017 weeks <br />3.91154e-4 months <br /> i

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SPECIAL REIOtT 88-18 Attachment 2 l Failure to Maintain Specific Activity of the l Primary System Nithin Administrative Limits '

PARAMETER DATE/ TIME VALUE-. l LETDOHh 22-Oct-88 02:00 70 GPM FLOW 23-Oct-88 00:15 75 GPM 24-Oct-88 00:20 70 GPM 25-Oct-88 05:40 75 GPH 26-Oct-88 02:00 70 GPH l

27-Oct-88 02:00 75 GPM 28-Oct-88 02:00 75 GPH 2 i k

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lo.o SPECIAL REPORT 88-18 Attachment 3 Failure to Maintain Specific Activity of the Primary Systen Within Administrative Limits BURNUP BATCH # # OF ASSEMBLES (MHD/MTU)

IE 1 20,800  !

SC 8 27,765 6B 16 28,183 7 32 24,214 i

8A 24 18.317 8B 40 17,767 f 9 56 5,812 i Note:. Core Average Burnup - 16,635 MHD/HTU l i

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