ML20197D663

Special Rept:Min Lower Limits of Detectability in Lake Water Sampling & Drinking Water Stations Exceeded Limits of Tech Specs.Caused by Inefficient Radiochemistry Counting Equipment.Water Samples Sent to Contractor

ML20197D663
Person / Time
Site:	Cook
Issue date:	05/01/1986
From:	Will Smith INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
NUDOCS 8605150012
Download: ML20197D663 (3)

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$ INDIANA & MICHIGAN EUCTRIC COMPANY DONALD C. COOK NUCLEAR PLANT P.O. Box 458, Bridgman, Michigan 49106 .

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FILE g Donald C. Cook Nuclear Plant Unit Nos. I and 2 Docket Nos. 50-315 and 50-316 e License Nos. DPR-58 and DPR-74 Mr. J. G. Keppler, Regional Administrator United States Nuclear Regulatory Commission Office of Inspection and Enforcement Region iIl 799 Roosevelt Road Glen Ellyn, IL 60137

Dear Mr. Keppler,

in accordance with Technical Specification 3.12.1 we are submitting this special report to advise you that the minimum lower limits of detectability in the lake water sampiing stations and the drinking water stations exceeded..the limits of Table 4-12.1. /'

During 1985 samples of water from Lake Michigan were composited by three (3) indicator and three (3) background stations. Samples collected throughout the year for the three (3) background stations were composited on a monthly basis and analyzed for gamma emitters and gross beta. Samples for 4he three (3) indicator stations were composited on a bi-monthly basis and analyzed for gamma emitters and gross beta. The results were included in the Annual Environmer.tal Operations Report for 1985 which was submitted on May 1, 1986.

It was identified by plant personnel th'at the radiochemistry counting equipment was unable to meet the required technical specification Lower Limits of Detection (LLD of T/S 4-12.1) and that the Minimum Detectable Activity (MDA) in some. cases exceeded the reporting values as specified in T/S 3.12.1. The LLD is defined as the detection capability for the instrument only using the equation in T/S Table 4.12-1 and the MDA, as the detection capability for a given instrument, procedure and type of sample.

This was not previously identified because the LLD values were never compared to the maximum values for LLD in Table 4.12-1 or the reporting levels required by T/S 3.12.1, We do not have the data to prove compilance with the LLD values frequired by T/S 4.12-1 since April 15, 1983 when the. Radiological Environmental Technical Specifications went into effect. However, the system backgrounds would have increased with time and efficiency reduced, both of which we believe, would generate LLD values equal to or lower than those presently obtainable. Prior to this date, no maximum values for LLD were requi red.

In two instances for Cs-134 and 1-131 the MDA values obtained exceeded the reporting i

levels in Technical Specification Table 3.12-2. The following is a comparison of the D. C. Cook Plant MDA, the Technical Specifications maximum value for the LLD (Table 4.12-1), Cook LLD limits, and the reporting levels required by Table 3.12.2.

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MAY 7 1986

Mr. J. G. K::ppler Mry 1,1986

- l' age 2 MAXIMUM LLD pCl/l COOK MDA VALUE- COOK LLD LIMITS REPORTING LEVEL pCI/I~

RADIONUCLIDE (T/S TABLE 4.12-1) pCi/l pCi/l (T/S TABLE 3.12-2)

Gross Beta 4 2700 - 3540 2700 - 3540 N/A-H-3 2000 500 - 610 500 - 610 20,000 Mn-54 15 29 2.8 1,000 Fe-59 30 57 15.4 400~

Co-58, 60 15 58, 49 15.8, 18.6 1,000 - 300 zn-65 30 40 15.6 300 zr-95 30 75 10.6 400 Nb-95 15 75 10.7 400

• l-131 1 48 4.9 2

• Cs-134 15 50 8.h 30 Cs-137 18 45 12.8 50 Ba-140 60 196 12.6 200 La-140 15 196 21.8 200~

• LLD > Reporting Level

• MDA > Reporting Level in addition to the cases of Cs-134 and 1-131 MDA values exceeding the reporting level, there was one instance where although the LLD value was less than the reporting level, the quarterly average concentration exceeded the reporting level. This occurred during the first quarter of 1985 for the lake water sample station L1 for Cs-137 The cause of this occurrence has been determined to be the elevated MDA values for two (2) months of the quarter when combined with the somewhat higher results for the third month of.the quarter.

' No elevated releases which would have been expected to increase the environmental

. sampling radioactivity levels above the maximum LLD were made at anytime. It is believed that the MDA being over'the required reporting level is an analytical problem and not a result of plant operations. These findings are summarized below:

RADIONUCLIDE SAMPLE STATION CALENDAR QUARTER -CAUSE Cs-134, 1-131 L1, L2, L3 1,2,3,4 MDA > Reporting Level St. Joseph 1, 2, 3, 4 MDA > Reporting Level Lake Township 1, 2, 3, 4 MDA > Reporting Level -l New Buffalo 1, 2, 3, 4 MDA > Reporting Level l l

Cs-137 L1' 1 Elevated MDA caused average l quarterly concentration to exceed reporting level.  ;

Mr. J. G. K;ppler -

p y 1, 1986 Page 3 ,

To prevent recurrence we have Started and wilI continue sending. the lake and drinking water samples to the radiological environmental monitoring program contractor, Control s for Envi ronmental Pollution, . In.c. (CEP), or another qualified laboratory with the capability to reach the required limits, in addition, a plant procedure now directs the review and compai'ison of the Radiological Environmental Monitoring Program Data to Technical Specification requirements.

The required LLD values currently achievable by CEP are summarized below:

t CEP DETECTION MAXIhUM LLD pCi/l RADIONUCLIDE ' LIMITS - OCi/1 (T/S TABLE 4.12-1)

Gross Beta 3 4 H-3 500 2000 Mn-54 2 15 Fe-59 3 30 Co-58, 60 5 15 l'

Zn-65 15 30 l Zr-95 5 30 Nb-95 5 15 l-131 1 1 Cs-134 7 15 -

Cs-137 2 18 Ba-140 4 60 La-140 4 15 Sincerely, '

W. G. Smith, Jr. h[ +

Plant Manager '

/sg cc: John E. Dolan R. C. Callen, EPSC B. A. Svensson M. P. Alexich G. Charnoff, Esq. 'A. A. Blind R. F. Kroeger D. Hahn Dottle Sherman, ANI Library C. A. Erikson INPO T. A. Kriesel R. W. Jurgensen PNSRC ,

R. J. Clendenning J. F. Stietzel S. R. Brewer NRC Resident inspector 6

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