ML20247F360

Rept of Interview W/Dr Mixa Re Knowledge of Alteration of Counting Times on Analysis for Radioactivity in Water Contained in Regenerate Holdup Tank

ML20247F360
Person / Time
Site:	Rancho Seco
Issue date:	01/26/1987
From:	Mixa D SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:
Shared Package
ML20247F042	List: IR 05000312/1986015 ML20247F039 ML20247F045 ML20247F082 ML20247F096 ML20247F107 ML20247F115 ML20247F133 ML20247F205 ML20247F262 ML20247F271 ML20247F287 ML20247F302 ML20247F327 ML20247F338 ML20247F341 ML20247F354 ML20247F360 ML20247F372 ML20247F380 ML20247F395 ML20247F413 ML20247F418 ML20247F438 ML20247F462 ML20247F469 ML20247F476 ML20247F487
References
FOIA-89-2, FOIA-89-A-7 NUDOCS 8905300062
Download: ML20247F360 (2)

Text

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f REPORT OF INTERVIEW WITH DAVID R. MIXA Date Interviewed: January 26, 1987 Date Dictated: February 5, 1987 01:RV Case Number: 5-Q&-010 On January 26, 1987, David R. MIXA, a Contract Analyst for Nuclear Support l

Services at the Sacramento Municipal Utility District's (SMUD) Rancho Seco Nuclear Generating Station (Rancho Seco), was interviewed by Senior Investigator, Ronald A. Meeks. MIXA was interviewed at NRC's Resident Inspector office at Rancho Secc. MIXA's business telephene is (209)333-2935.

MIXA was interviewed relative to his knowledge of the alteration of counting times on anal l Holdup Tank RHUT)

(ysis for radioactivity at Rancho Seco. in water contained in the Regenerate l With respect to the alteration of counting time, MIXA stated: ,

l ~

1. MIXA, from April 1984 to October 1985, was a Chemical and Radiation Protection Technician at Rancho Seco.

2. When MIXA started work in 1984, he recalled instructions on the bul.letin board in the Chem. Lab regarding the counting time. When the Canberra Computer Program was implemented in the first part of 1985, the program was set up on a 3000 second count. It was realized that Rancho Seco could meet the Lower Limits of Detection (LLD) with a 2000 second count then the switch was made to 2000 seconds, i 3. There were no procedures or documented instructions concerning the 2000 l

second count but information was written on the bulletin board in the Chem. Lab regarding the 2000 second count.

4 MIXA had the impression that the muligcti.vits detected at 2000 seconds on March 29 19856 might have been the catalys$ for instituting a lower 1000-second soun$. MIXA made the activity entry into the radiation log l book and reported to the Control Room Operator that the RHUT could not be released because of the indication of radioactivity. MIXA believes that possibly the Control Room Operator was Al FRAZIER'.

5. After reporting the peak to the Control Room, MIXA was contacted by KELLEY, who inquired about the activity. MIXA recalled that the water was backed up in the plant and needed to be released. KELLEY instructed MIXA to redo the analysis on the RHUT using a counting time of 1000

\ seconds 6nd if no peaks were identified, then proceed with the release.

g KELLEY's basis for doing this was the need to release the waten

\

6. Steve MANOFSKY later reviewed the situation and concurred with KELLEY concerning a 1000 second count in order to preclude the peaks of radio-activity detected at 2000 seconds. ,

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7 MIXA felt uncomfortable in lowering the counting time to 100'O seconds and reporting to the Control Room that there was no activity when in fact de knew there was activity'regardless of the LLD being below Rancho t

Seco's required LLD.

- 8. It was MIXA's understanding.that the reduction in'the count time was done so that SMUD could maintain their public commitment of not releasing any radioactive isotooes to the environment. .

9. Bil1. WILSON was not involved in the March 20, 1985, 2000/1000 second count times but he did concur with KELLEY and MANOFSKY concerning the alteration of counting time on other occasions.

10. The pressure.from tne. Control Room sometimes~was excessive in that the Control Room Operators were anxious to have the water released as soon as possible. - At times, the Control Room Operator.would notify MIXAi during the middle of his analysis inquirino if it appeared the water would be able to be released. MIXA recalls specifically talking to Al FRAZIER several times concerning the release of water in conjunction with MIXA'sLanalysis..

11. MIXA explained when radioactivity peaks were identkfied at a 2000 second count, then a second count was run. If peaks were still identified on' the second 2000 count, then the water was returned back to the system.

If the second count was negative regarding detected peaks, then a third count was conducted and any positive indications caused the water to be sent back and any negative indications allowed the water to be released.

12. If peaks were identified on 1000 second counts, then the water was returned to the system. It was nec u:rommon to return water for reprocessing during 1000 second count ar.alyses.

13. MIXA stated that he always notified the Control Room of identified

' activity during 2000 second counts.

14 MIXA explained that the detection equipment is very sensitive and any f changes such as replacing the RHUT liners or receiving water from the secondary systems sumps could cause indications of higher radioactivity.

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