ML20129B795

Provides Comments Resulting from 960827-28 Insp Activities of ISFSI Site Survey to Verify Survey Adequate to Demonstrate Planned Site Can Meet Council Free Release Criteria Prior to Transfer of Spent Fuel to Dry Storage

ML20129B795
Person / Time
Site:	Trojan  File:Portland General Electric icon.png
Issue date:	09/11/1996
From:	Stewartsmith D OREGON, STATE OF
To:	Megehee M PORTLAND GENERAL ELECTRIC CO.
References
NUDOCS 9609230265
Download: ML20129B795 (2)

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DEPARTMENT OF September 11,1996 ENERGY dk R, -o/M Margaret Megehee Trojan Nuclear Plant 71760 Columbia River highway Rainier, OR 97048

Dear Ms. Megehee,

On August 27 and 28,1996, the Oregon Offlice of Energy and Oregon Health Division, Radiation Protection Services, perfomed ajoint inspection of the Independent Spent Fuel Storage Installation (ISFSI) site survey. The inspection reviewed survey practices and procedures, and '

samples were taken to verify that your survey was adequate to demonstrate that the planned ISFSI site can meet the Council's free release criteria prior to the transfer of spent fuel to dry storage. As a result of our inspection activities, we have the following comments:

1. In the Affected area (the area formerly occupied by the Radwaste Storage Annex),100%

surface scans were performed using a'CM-11 detector. The detector used bottled P-10 gas. The detector was calibrated at approximately 20 degrees centrigrade prior to the survey, and a source check was performed every morning. Since the operating temp ature j during the survey, which was in the direct sunlight, was up to 15 degrees centigrade -

greater than the temprature at which the calibrations were done in the laboratory, and there was no calibration check with a radiation source in the field, did the heating effect in l the gas bottles affect the efficiency of the CM-11 detectors?

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2. We noted that the soil sample locations are identified according to their location on the site survey map (page 3 of the survey plan). Pursuant to the plan, there are only indirect ways to identify the absloute location (i.e., by Township, Range, minutes and seconds)' of samples. Your system ofidentifying soil sample locations is acceptable, but does not provide an absolute location, which could be helpful in the future, 9

particularly if the survey's validity is challenged. We suggest you consider some method ofproviding an absloute location for soil samples and survey measurements.

M@ f4 John A. Kdzhaber Governor

3. We reviewed calibration procedures for the intrinsic Germanium detector and gamma spectroscopy system. The calibration standard  ? 'y used to calibrate this system is lower in density (1.15 g/cc) than the N /

soil that is being analyzed (over 2 g/cc). This will result in reduced 625 Manon Street NE l IrFNSING satem. on 97310 a e,a ne7, vg

~vvU (503) 378-4040 FAX (503) 373 7806

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September 11,1996 Page 2 I 1

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detector efficiency, expecially at low energy levels. Does this have any significant effect i on the samples you are analyzing, and ifnot, why not? The inspection also noted that a~ i

' daily check of the energy calibration and the peak resolution (FWHM) was being l

. performed. You should consider allowing the gamma analysis system to go through the '

quantificadon of radionuclides in the standard on some frequency as well. This will serve as a more complete system check. We noted that when the system was recalibrated with a new gamma standard in the spring of 1996, the apparent detector efficiency at very low

. energies (Co-57) was considerably different that three years earlier. This may be due to detector instability after not being used for nearly three years. If detector efficiency has drified in the meantime, such a periodic analysis of the standard will pinpoint the problem.

4. The Health Division survey showed that there appeared to be a significant mcrease m background (up to 2 times) at the corner of the fenced area opposite the corner of the spent fuel building. This is not unexpected. However, using the decommissioning plan . ,

criteria and current waste inventory, there should be a correction calculated. This would

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show that survey measurements in this area are in part due to the influence of waste storage, and will not be co'nsidered the background against which final site release will be

• based.

Please respond to these comments. Ifyou have any questions regarding this inspection, I would be happy to discuss them with you.

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Sinply, 0,- -

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end i My wa l

' David A. St wa -Smith '

Administrator, Energy Resources cc: Larry Rocha, PGE Steve Quenoz, PGE Vince Everett, NRC Region IV l Mike Masnick, NRC NRR Richard Bangart, NRC Office of State Programs Martha Dibblee, Health Division Tom Johnson, Health Division I

. EFSC Members j i

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