ML20024B993
| ML20024B993 | |
| Person / Time | |
|---|---|
| Site: | 07001359 |
| Issue date: | 06/16/1983 |
| From: | Book H, Grayson W, Thomas R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML20024B991 | List: |
| References | |
| 70-1359-83-01, 70-1359-83-1, NUDOCS 8307120101 | |
| Download: ML20024B993 (6) | |
Text
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U.S. NUCLEAR REGULATORY COMMISSION REGION V Report No. 70-1359/83-01 License No. SNM-1405 Licensee:
IRT Corporation 7650 Convoy: Court San'Diego, California 92138 Facility Name:
IRT Corporation Inspection at:
7070 Convoy Court Inspection Conducted: May 19, 1983 Inspector:, (dm MdAk_
(1#A (p!/393 Wm. Mark Grayson, Radiatton Specialist Dat'e Signed Approved by:
W d
d R. D. Thomas, Chief, Materials Radiation Date Signed Protection Inspection and Licensing Section Approved by:
h.
[ /!-!N H.' E. Book, Chief, Radiological Safety Branch Dat'e Signed Summary:
Inspec_ tion of March 19, 1983 (Report No. 70-1359/83-01)
The licensee in a January 25, 1983 letter to the Uranium Fuel Licensing Branch requested that SNM license be amended to delete the 7070 Convoy Court building as a use location. The Uranium Fuel Licensing Branch in a March 17, 1983 letter requested that the Region V Radiological Safety Branch perform a confirmatory survey of that use location.
On May 19, 1983, one Region V inspector conducted a confirmatory survey of the area. The survey consisted of the measurement of alpha, beta and gamma radiation exposure levels and the collection of swipes throughout facility to verify residual contamination levels were within; " Guidelines For Release Of Facilities And Equipment Prior To Their Release For Unrestricted Use", July 1982.
Based on the results of this survey, it was determined that the 7070 Convoy Court use location meets the criteria for release to unrestricted use.
This survey involved a total of five manhours on-site, utilizing one NRC inspector.
8307120101 830700' PDR ADDCK 07001359 C
l DETAILS A.
Persons Contacted Kay L. Crosbie, Radiation Safet'y Officer P. R. Maschka, Senior Health Physicist B.
Background
In correspondence to the NRC dated January. 25, 1983,' the licensee requested an amendment to delete their facilities at 7070 Convoy Court, as an authorized place of use under their SNM-1405 license. The licensee stated in their amendment request that no SNM was ever utilized at that location and that their confirmatory release survey of the building indicated that no radiation levels above background were detected. The Uranium Fuel Licensing Branch in a March 17, 1983 letter requested that the Region V, Radiological Safety Branch verify that residual contamination levels were as stated by the licensee in their January 25, 1983 letter, prior to completion of the requested licensing action.
C.
Procedure 1.
Radiation Survey Equipment An Eberline PRM-7, Micro-R-Meter, NRC No. 010839, due for calibration on August 16, 1983, was used to detect low level gamma contamination and to measure gamma exposure rates.
A Ludlum Model #12, alpha meter, NRC No. 003564, due for calibration on August 7,1983 was utilized to survey for alpha contamination and to measure alpha radiation exposure rates.
An Eberline E-520, NRC No. 008253, due for calibration on June 14, 1983 was utilized in conjunction with the HP-260 probe to detect alpha, beta, or gamma contamination and to perform a qualitative survey of swipes onsite.
Contamination swipes were counted at the Region V Office utilizing a Tennelec L13-5100, S.O. #57514, gas flow proportional counter.
2.
Survey Techniques and Sampling Locations Three separate surveys were taken of the 7070 Convoy Court location.
An initial survey was performed with the Eberline PRM-7 Micro-R-Meter, keying on the low level gamma emissicas associated with SNM, to determine whether any residual radioactive contamination was pres,ent. A detailed survey of the entire facility was performed as indicated in Attachment A.
The grid utilized for this survey was to take the facility and divide it systematically into three foot strips. These three foot strips were then surveyed at ground level in a zig-zag pattern to assure better then 90%
coverage of all floor surface area. Surveys were
2 also taken of walls, light switches, pipes, restrooms, door knobs, fixtures, trash containers, and equipment still present inside the facility.
In addition, selected floor locations, entrances into the bathrooms, bathroom fixtures, trash cans, some walls, a. drain, and several electrical outlets were also surveyed with an Eberline E-520 with the HP-260 pancake probe, as a cross check for alpha and gamma contamination and to assure that beta contamination was also absent from these locations. A secondary survey for.SNM or other alpha emitters was conducted using the Ludlum Model 12, Alpha Meter.
Prior to use, the instrument was checked with a Pu-239 alpha source.
The instrument was found to be operating at a 46% efficiency and registered approximately 4300 cpm.
Since this was the same efficiency found for that source-instrument combination before transport to the licensee, the instrument was found to be operating properly. The grid used for these surveys was to divide the facility up into approximately six foot wide rows, detailed spot surveys of the surface of the floor were t'aken at two locations on each row. Floor coverage was estimated to be between 15% to 20% of the total' building floor area. A third survey was performed utilizing swipes to detect removable alpha, beta, or gamma contamination. A survey map similar to that used by the licensee, with the exception of additional swipes, is provided as Attachment B.
An estimated 8% to 10% of the total floor space was covered during this third survey.
C.
Results 1.
Background radiation level measurements taken with the Eberline PRM-7 Micre 2-Meter, outside the 7070 Convoy Court facility, ranged from 8 ur/hr to 12 ur/hr. An average value of 10 ur/hr was used to evaluate the interior survey results. The interior survey results fluctuated very little with no readings significantly above background for any of the areas surveyed. Survey results using the Eberline E-520 with the HP 260 pancake probe as a crosscheck also indicated that no surface contamination was present.
2.
Background alpha contamination levels measured with the Ludlum Model
- 12 alpha instrument were determined by measuring several spots i
outside the building as well as the lowest values found in accessible interior locations. Thus, the background level selected would take into account the potential differences associated with l
the interior concrete versus the asphalt surveyed outside. A value of 10 dpm was determined to be representative based on review of the survey meter results at these locations. Alpha contamination levels j
fluctuated very little from the background measurement and were not considered to be statistically significant.
l l
3.
The swipe survey results are summarized below. Each area smeared j
consisted of approximately 100 square centimeters. The efficiency of the Tennelec L13-5100 for alpha counting, was 38%, the efficiency utilized for beta / gamma counting was 10%.
The background count rate of the Tennelec L13-5100 for alpha radiation was determined to be
.15 dpm, and 9.9 dpm for beta gamma radiation.
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The maximum amount of alpha contamination found during this survey, afterbackgroungandefficiencycorrections,wasdeterminedtobe 1.18 dpe/100 cm. LThe maximum amount of beta gamma contamination found during this survey, after background and effjciency corrections, was determined to be 11.10 dpm/100 cm.
D. ' Conclusions-U$111zingjhefsurfacecontaminationlevel'guidelinesof1000 alpha
.- dpm/100- cm ' and 1000 beta-gamma dpm/100 cm contained in " Guidelines'for Deco'ntamination of Facilities and Equipment Prior to Release for Unrestricted Us':or, Termination of Licensees for Byproduct, Source, or e
.Special Nuclear Material," July 1982, the results of this survey showed alpha. contamination. levels to be.1% of the release limit and beta-gamma contamination levels to b'e 1.1% of the acceptable release limit. Based
-_'on the'results of the three radiation level surveys and the contamination survey it is. concluded that the licensee's 7070 Convo= Court location is a
within acceptable guidelines and can be released for cz..astricted use.
l
ATTACHMENT A CONFIRMATORY SURVEY GRIDS Initial gamma survey with Eberline PRfi-7 (Rows on approximately 3' centers)
Alpha survey with Ludlum tiodel #12 (Rows on approximately 6' centers)
At least 2 locations per row were surveyed in detail
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