ML20205E971
| ML20205E971 | |
| Person / Time | |
|---|---|
| Site: | Wood River Junction |
| Issue date: | 03/16/1987 |
| From: | Velasquez J UNITED NUCLEAR CORP. (SUBS. OF UNC, INC.) |
| To: | Crow W NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| 27985, NUDOCS 8703310056 | |
| Download: ML20205E971 (6) | |
Text
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RETURN TO 396-SS PDR/LPDR
.4 UnC mining AnD MILLING Unc o*oa o' un. tea nuciear corporation e o. 80,848o A UnC RESOURCES Company Santa Fe, New Mexico A75 4480 Telephone 505/988-9208 o~
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March 16, 1987 8
m Mr.
W.J.
Crow, Acting Chief to" /
Uranium Fuel Licensing Branch l'N Division of Fuel Cycle and Materials SMe'ty,_NWQ 9;
MAR 191987-) -Q U.S.
Nuclear Regulatory Commission
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Dear Mr. Crow,
y co Regarding continued decommissioning efforts at our facility at Wood River Junction, Rhode Island, this letter serves to notify you of our proposed activities to review and as necessary to further decontaminate the grid blocks identified by your staff at our February meeting.
By way of confirmation, it is our understanding that NRC continues to be concerned about the status of grid blocks D-069, D-070, D-072, D-078, D-085, D-094, D-096 and B-126.
NRC's concerns arise from the results of soils analyses obtained by NRC's contractor, ORAU.
PROTOCOL DIFFERENCES Before delineating our proposed actions I would like to discuss our view of ORAU's results and their implication for our facility. As you are aware, we continue to be concerned that the procedures ORAU has used in conducting its confirmatory survey sampling oresent a problem in determining dose commitment data per target criteria and cleanup requirements as prescribed for this site by NRC. We have expressed our concern in the past regarding the differences in protocols used by ORAU and UNC's vendor laboratory,
- CEP, in sample gathering, preparation and analysis. We believe that procedures used by ORAU have caused some samples to be biased high and do not represent the true radiological condition of the grid block per the soil decontamination criteria. For instance, in gathering its samples ORAU did not appear to use a systematic methodology. In addition, some of the samples were taken based on meter readings. Also, ORAU has analyzed its samples using gamma spectrometry rather than alpha spectrometry which had previously been agreed to. Use of gamma spectrometry can lead to generally higher results and is less sensitive (e.g. the limits of error can equal or exceed the stated sample value). Also complicating the interpretation of the results of our respective labs is.the problem of non-homogeneity
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. The results of the ORAU sampling and analytic methods have been interpreted in many cases to represent the condition of the entire grid block causing the whole block to be suspected of being contaminated.
We believe that if ORAU had used methods identical to those used by UNC's vendor laboratory, thus generating average values for the soils within the grid blocks, their results would have allowed them to conclude that the soil at the site met NRC's criteria. Unfortunately, the difference in protocols used by UNC in conducting its survey and those used by ORAU in performing the confirmatory surveys have resulted in disagreement concerning the contamination status of particular grid blocks. The difference in analytical results can be attributed in the difference in protocols and does not reflect " good" or " bad" results.
In an effort to resolve these differences we are willing to conduct certain additional cleanup activity in the grid blocks of concern. However, we would like to ensure that the evaluation methods used by ORAU and our laboratory are identical in order to minimize the possibility of widely varying results.
It is important, in our view, that ORAU and our vendor laboratory use the same protocol.
Therefore, per our discussions during our February meeting, we propose the following procedures to resolve our respective concerns.
- 1. UNC will review each block and determine what remedial action it will undertake.
- 2. After the action has been completed, UNC and NRC (ORAU) will jointly gather representative samples from each grid block where this is possible (with NRC Region I assistance).
- 3. UNC and NRC will work with their respective contractors (CEP and ORAU) to develop an agreed upon protocol for sample preparation and analysis. The samples will be split three ways after preparation and analyzed independently using the agreed upon methodology.
4.
The third split of each sample will be archived pending the comparison of results from ORAU and CEP.
If widely divergent results occur the differences will be resolved by using a mutually agreed upon referee laboratory to whom the third split of the sample (s) will be submitted for analysis.
UNC is already in contact with ORAU and CEP. We hope to effect this procedure as soon as weather permits.
REVIEW OF SPECIFIC GRID BLOCKS Following is a discussion of our review of the grids of continued concern as identified in our February meeting.
We include a discussion of our proposed action where appropriate.
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. D-069 & D-070 These grid blocks are in an area largely covered by macadam.
They.also contain the concrete loading dock well and an office trailer. Discussions with Mr. Berger of ORAU indicate that he took his samples from a long narrow three feet wide strip of soil between the trailer and concrete block wall, the only exposed soil in these blocks. Such samples should_be treated as locally biased samples not representative of average concentrations within in the 30 ft, by 30 ft. grid block.
UNC does not agree that these blocks require additional cleaning. Nonetheless, UNC will skim and remove the surface soil from the area in question to allow samples to be taken for comparison.
D-072 This grid block is entirely covered by macadam.
It is i
unclear to us where ORAU took its soils sample as there is no soil-exposed. There may have been some blow sand deposits in a l
depression in the macadam.
- However, such a sample would not j
constitute a representative sample of the grid block. It is also possible that the sampling procedure removed whatever contamination was present. UNC will sweep up any visible deposits of soil.on the macadam such that no additional sampling will be l'
necessary.
D-078 & D-085 These grid blocks are also almost completely covered by i-macadam with the exception of a ten ft. by ten ft.,
- fenced, transformer enclosure. Construction of this specialized enclosure includes a concrete pad supporting the transformer with about I
three feet of trap rock surrounding the pad out to the fence. The layer of trap rock is about thirty inches deep to act as a water diverting dry well to protect the transformer from submersion. In discussions with Mr. Berger at the February meeting and later by telephone, it was his recollection that he scooped his samples from dirt that had been deposited around the bottom of the fence and from joints between the macadam and the concrete retaining wall of the truck well. These are not representative samples and UNC cannot agree that these grid blocks are contaminated.
Nonetheless, UNC will skim and remove as much soil as is evident and sweep up the macadam.
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, -l D-094 This grid block contains.a macadam surface with an excavated hole approximately 10ft by 10ft by 4ft(deep). The' hole resulted from excavation and removal of materials identified by ORAU as being contaminated based on ORAU's meter readings, indicating elevated levels. of contamination 1 inside a four inch diameter conduit..UNC removed the incinerator pad, the conduit, and a
- sizeable amount of soil under the pad. An additional.one foot of soil wari then removed from the' entire excavation. Thus, ORAU's sample indicating contamination in the area around the old incinerator pad was taken prior to UNC's final act of decontamination. UNC's subsequent sample analysis indicates that this area is now free of contamination, and we plan no further action on this block.
D-096 This grid block contains an area that is approximately one-third covered with macadam,- an area of soil at a_ surface level even with the macadam approximately 100 feet square, and an area approximately 500 feet square that has already been excavated to a depth of 4 ft. Both UNC and ORAU are uncertain as to where ORAU took their_ samples. However, comments at the February meeting leads us to-believe that they were taken on the slope between the original surface and the bottom of the excavation. If so, UNC does not believe such a sample is representative of the average conditions within the grid. Nonetheless, UNC will sample this grid block in accordance with the decommissioning criteria and determine if it is necessary to conduct additional remedial action. If so, UNC will skim and remove additional soil.
B-126 This grid block is approximately half covered by macadam.
The balance of this block has already been excavated, early in the program, to a depth of over two feet and backfilled with soil. Additionally, in response to a previous NRC contamination
- concern, an area of approximately sixteen feet square was excavated to a depth of three feet.
Both UNC and ORAU are uncertain as to where ORAU took their samples and we question whether the ORAU sample is representative of the entire block.
Nevertheless, UNC will resample the soil in the block in accordance with the decommissioning protocol and determine if additional remedial action is necessary. If so, UNC will skim and remove soil from the area not covered with macadam.
e Upon completion of the work as described above, UNC will contact Mr.
Roth of NRC's Region I,
the site's principal investigator, and request that he and Mr. Berger schedule a site visit for the purpose of acquiring verification samples in accordance with the agreed upon protocol we discussed at our February meeting and described above.
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. CONCLUSION It is important to reiterate that UNC considers that the soils at the site have been decontaminated to well within the criteria as set forth in NRC's document titled, " Soil Decontam-ination Criteria for the Decomissioning of UNC's Facility", in accordance with the ALARA concept. We have decommissioned and decontaminated the site in accordance with regulatory mandate using NRC's guidance.
We believe that the dose commitment attributable to this site is sufficiently low so as to warrant release of the site for unrestricted use and termination of the NRC license once the drummed waste has been removed from the site.
At the February meeting members of your staff made note that the regulatory goal of decommissioning and decontamination is to ensure protection of the public by keeping radiation exposures to within criteria determined as applicable for unrestricted use and keeping exposures as low as reasonably achievable. UNC believes it has accomplished D&D well within this framework.
We will conduct the additional work described herein to demonstrate our commitment to the ALARA principle as it is our hope that once this its work is concluded, we can proceed with termination of the license.
Sincerely rs, sm Juan R. Velasque Manager, Environmenta ffairs JRV/mn UNCALO2Q 1
JerryRoth-NRCReg{onI cc:
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