ML20198D830
| ML20198D830 | |
| Person / Time | |
|---|---|
| Site: | Wood River Junction |
| Issue date: | 05/02/1986 |
| From: | Gregg R UNC, INC. (FORMERLY UNC RESOURCES, INC.) |
| To: | Crow W NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| 26956, NUDOCS 8605270073 | |
| Download: ML20198D830 (9) | |
Text
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Uf1C RECOVERYGYSTGm5 6
RETURN TO 396-SS Dwision of Umtec Nuclear Corporation One Narragansett Tra:t Telephone 401/364-7701 A Unc RESDURCES Compan/
Wood River Junction. Rhode Island 02834 May 2, 1986 3
f.N.
W. T.
Crow, Acting Chief Uranium Fuel Licensing Branch gQM Division of Fuel Cycle and Material Safety, NMSS 8 $86
- C United States Nuclear Regulatory Commission SI M
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Washington, D.C.
20555 C
45-3 s10 #
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Gentlemen:
Reference:
(1)
Letter, W. T. Crow to Robert J. Gregg N m
dated October 29, 1985 (2)
Letter, James D.
Berger to William Crow dated February 24, 1986 The reference (1) letter forwarded ORAU soil sample Isotopic Uranium analysis results (later modified by reference (2), as well as a request for UNC actions and schedules for completion of soil decontamination efforts.
We are currently in the process of performing additional soil removal, as requested by the NRC and agreed to in our meeting of September 6, 1985, and as further discussed with J.
Roth of Region I during his visit on March 4, 1986.
The details of that effort and the schedule for completion are included in the attachment to this letter.
In addition, we have reviewed available information, relative to Uranium isotopic ratios, and to the information provided by ORAU in their draft report, and have included our comments on those subjects in the attachment.
We would appreciate your action to obtain ORAU's reports on the remainder of their decontamination confirmation survey (i.e.,
for the buildings and the areas outside of the controlled area) so that we can finalize plans for prompt license termination.
We would be pleased to discuss these matters further with you, NRC Region I, and ORAU at your convenience.
I very truly yours, g
A bu m,i FEE ll0TrI fj[
R. 3. Greg Plant Manager k
M RC UNC Recovery Systems MAY 81986 > C cc:
J.
Roth (NRC Region I) h yg T
G.
O. Amy Docm cts K. Helgeson g
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Attachment M Letter. Ed. Grega M W.T. Crp_w. dated tiEP.L.L931 w
Additional SDRDecontamination Actions In the meeting held between UNC and the NRC on September 6,1986, the NRC, based on ORAU interim soll survey results, identified areas in which they felt that additional soll removal should be performed. UNC felt at the time and continues to feel that most of the areas identified by the NRC met the official decontamination criteria provided to us. However, we have attempted to satisfy the NRC's concerns by performing additional soil removal in all such areas. The attached plot plan and accompanying table provide specific information regarding the extent of that effort. The work being performed was reviewed with Mr. J. Roth of the NRC's Region I office during his site visit on March 4,1986. We anticipate completion of all the indicated soll removal by the end of May,1986, and request that the NRC schedule any planned confirmatory surveys for the month of June,1986 so as to minimize any additional time necessary to complete license termination activities.
Discussion, it should be apparent from a review of the attached soil removal tabulation that UNC has significantly exceeded the effort that would have been needed to specifically address the items of concern identified by the ORAU results.
- 1. The official site-specific NRC soil decontamination criteria provided to UNC relate to radiation dose rates to humans occupying the site in the forseeable future, under what are essentially worst case exposure conditions. Those criteria are for average radioactivity levels, with the exception of a local criteria for gamma dose rate. The areas of NRC concern were, for the most part, based on local measurements made by ORAU. In fact, in no case did ORAU actually determine average values, but instead measured discrete local conditions. In fact, some measurements clearly reflected discrete conditions (it is apparent in a couple of cases that the material creating the elevated reading was completely removed in ORAU's analytical sample). Nonetheless, nearly all of UNC's additional soil removal has been done on the premise that the ORAU results were representative of large areas. For example, in several cases, a local measurement by ORAU was addressed by removal of soil from a complete 30' by 30' grid block.
Attachment M Letter. &1 Grega M W.T. [Irgw. dated ti_g 1193.5 konL1
- 2. UNC had reviewed the information relative to Uranium isotopic ratios included in the reference (1) letter, and compared it with other available data. Based on that review, we had concluded that the ORAU U-234:U-235 ratio was biased high. This conclusion was subsequently substantiated by the reference (2) letter, which indicated there had been an error in ORAU's computer program. Our information indicates that the true average ratto is approximately 24:1, with a range between 16:1 and 31:1-This conclusion is based on actual material certification values for material processed at UNC Recovery Systems; on NRC measurements made of lagoon materials; and on NRC values reported in the site-specific guidelines for decontamination of the Rhode Island facility. This information, which is all from analyses of material with a much higher level of Uranium than was present in the soll taken from decontaminated areas of our facility for the ORAU analyses, is summarized in the following table:
MATERIAL u-234U23s Ratios MIN MAX AVERAGE NOTES 93% ENR. Uo2 - PRODUCT (6 Lots) 17.50 18.54 15.09 18.00 NPo MATERIAL - 93% ENR 31.00 NPD MATERIAL - 972 ENR.
NRC ANALYSES 0F LAGo0N MAT 1. (9) 16.33 31.24 23.48 (1)
NRC ANALYSES OF LAGo0N LIQUIDS (4) 23.81 30.23 27.s7 (2)
NRC ANALYSES OF TEST WELLS (2) 2s.00 29.58 27.29 (2)
GRAND AVERAGE (23 ITENs) 23.21 NOTES:
(1) REF. NRC INSPECTION REPORT 70-820/80-19 DATED MAY 26,198 I (2) REF. APPENDIX C To NRC soll DECONTAMINATION CRITERIA FOR THE DECOMMISSIONING l
OF THE UNCS FACILITY (SCRAP RECOVERY FACILITY; Wo0D RIVER JUNCTION, R.I.)
l It is particularly interesting to note the consistency of results obtained from-the higher concentration materials, both within a series of analyses i
and between the NRC and UNC, as opposed to the large variability between analyses of lower concentration materials taken from decontaminated areas of the site.
This is no doubt a result of the ability of the analytical technique to more precisely quantify Uranium levels when they exist as a l
higher percentage of the total sample content.
2
Attachment [q Lqttin R J. Greaa tq W.T. Crow dated May 2 1986 (cont.)
Since the areas identified by the NRC as needing additional soil removal were in part selected based on ORAU's erroneous U-234.U-235 ratio of 35:1, and since UNC performed additional soil removal in all of those areas, it is again apparent that the additional work performed by UNC exceeds the minimum that would have been needed to satisfy the NRC's concerns.
With respect to the ORAU araf t report, there are some specific items which merit discussion.
First, the NRC soil decontamination criteria specifically relate to readings above background. The ORAU report does not consider background levels. For example, in the first paragraph of their discussion of results, ORAU talks about a 10 pR/h limit for gamma exposure, and mentions isolated locations which exceed that limit. Including the 11.33 pR/h background, the actual limit would be 21.33.
Second, in addition to ORAU's failure to consider background, the 10 pR/h limit is for a diffuse cource (a contaminated area greater than 30' by 30'),
and the local limit is 10pR/h higher. Since no diffuse source calculations were made by ORAU, the use of that limit is inappropriate. Of all of the local readings taken by ORAU, only one exceeded the 31.33 local limit (33 in grid block D078), and that was founo during a walkover scan which was directed at finding the highest discrete location readings in the whole survey area.
Therefore, while the radiation data in the draft report support the fact the UNC had met the NRC's decontamination criteria, the treatment of that data indicates the opposite.
UNC assumes that these and any other discrepancies will be corrected in the final report.
3
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Uf1C Attachment to Letter, R.J.
Grecq to W.T.
Crow dated May 2, 1986 (Conti UNC RECOVERX_ SYSTEMS SOIL DECONTAMINATION GRID BLOCK #
DESCRIPTION OF ADDITIONAL SOIL REMOVAL D-064 l'
of soil removed from strip between the D-072 warehouse and macadam area D-066 As above D-067 As above D-068 l' of soil removed from small soil area near fence and drain (remainder of block is macadam)
D-078 Swept up and removed soil on macadam near bottle rack (whole block is macadam)
D-081 Removed soil from macadam near drain (whole block is macadam)
D-089-Removed 6" of soil from complete area not covered by macadam D-092 Removed 6" of soil from a 10' by 10' square centered on the grid block center D-094 Removed strip of soil 2' wide by 3' deep around the incinerator pad D-096 Removed l' soil from a 10' by 10' square centered on a spot 4' S and 4' W of the grid block center B-002 Cdntamination removed immediately after ORAU walkover survey B-021 Removed 6" of soil from the complete grid block B-023 Removed 6" of soil from a 10' by 10' square centered on the grid block centerline 5
AC Attachment to Letter. R.J. Greca to W.T.
Crow dated May 2.
1986 (Cont)
' GRID BLOCE._f.
DESCRIPTION OF ADDITIONAL SOIL REMOVAL B-027 Removed 6" soil from a 10' by 10' square centered on a spot 9' N and 12' W of the grid block center B-028 Removed 6" of soil from the complete grid block B-037 Removed 6" of soil from a 10' by 10' square centered on a spot 4' N and l' E of the grid block center B-050 Removed 6" of soil from a 10' by 10' square centered on a spot 7' N and 12' E of the grid block center B-055 Removed 6" of soil from the complete' grid block B-064 As above B-082 Removed 6" of soil from a 10' by 10' square centered-on a spot 6' S and 7' W of the grid block center B-083 Removed 6" of soil from the complete grid block B-084 Removed 6" of soil from the complete grid block B-085 Removed l' of soil from the complete grid block B-126 Removed 6" of soil from block area not covered by macadam.
Then at a spot l' S and 8' E of -
the grid block center, removed 4' of soil from a 4 ' by 4 ' square, centered on the above coordinates.
B-130 Removed 6" of soil from a 10' by 10' square centered on the center of the grid block 6
1
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OC Attachment to Letter. R.J. Greca to W.T.
Crow dated May 2.
1986 (Cont)
GRID BLO_QJLJ
. DESCRIPTION OF ADDITIONAL SOIL REMO_yAL B-134 Removed 6" of soil from the complete grid block B-135 As above B-137 Removed 6" of soil from a 10' by 10' square centered on a spot 6' S and 7' E of the grid block center B-138 Removed 6" of. soil'from the complete grid block.. Removed 4' of soil from a spot 10' by 10.' square, centered on a spot 18' N on the centerline of the grid block B-139 Removed'4' of soil'from a 10' by 10' square centered on a spot 3' N and 4' E of the center of.the grid block B-140 Removed 2' of soil from a 10' by 10' square centered on a spot.2' N and 10' W of the center of the grid block.
B-141 Removed 6" of soil from a 10' by 10' square centered.on a spot *'3' S and 10' E of the grid block center l
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