ML20210P380
| ML20210P380 | |
| Person / Time | |
|---|---|
| Site: | 07000824 |
| Issue date: | 03/25/1986 |
| From: | Olsen A BABCOCK & WILCOX CO. |
| To: | NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| 26722, NUDOCS 8605130347 | |
| Download: ML20210P380 (12) | |
Text
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337ug3 To 396-ss PD Research & Development Division Babcock & Wilcox tynenburo n....rch c.ni.,
P. O. Box 11165 March 25, 1986
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URANIUM PROCESS LICENSING SECTION E
APR 1M IUM FUEL LICENSING BRANCH u.s NUCL
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Reference:
Report No. 70-824/85 Gentlemen:
This submittal contains information in response to findirgs by Region _II inspectors as a result of a closeout inspection and confirmatory survey as listed in Section 7 of the referenced report. The responses are presented in the attached Appendix A.
These responses were discussed with Mr. Ketzlach at a meeting at our facility on March 13, 1986.
Appendix B is a floor plan of Building C, showing the decommissioning phase boundries.
Appendix C contains a listing of action items that the Lynchburg Research Center feels are necessary to close out the refc.renced findings.
Prompt resolution of these action items is needed to atsure us that we can proceed with the refurbishment of Phase I with confidence that further surveys of this area are unnecessary.
If you have questions regarding any of the information provided, please don't hesitate to phone me or Mr. Gary S. Hoovler.
Very truly yours, BABC0CK & WILC0X Lynchburg Research Center L A 0%
Arne F. Olsen m
Senior License Administrator
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-ATTACHMENT A
-LRC RESPONSE TO NRC' FINDINGS IN REPORT NO. 70-824/85-08 FORWARDED BY 2/13/86 LETTER FROM J. PHILLIP ST0HR TO T. C. ENGELDER March 18, 1986 e
a
NRC Finding a:
"The site gaseous effluent stack is located adjacent to the fan room in the south-west portion of Phase I and penetrates through the building roof. The stack is still in service. The off gas ducting from Building B (hot cells) runs along the ceiling in Phase I to the stack.
Figure 2-4 of the licensee's May 28, 1985 final survey report (Appendix A) indicated that the stack was to be included in the area to be released under Phase I.
The inspector stated that the off gas system and stack could not be released if it was still in service. Additionally, releasing Building C for unrestricted use would cause the site gaseous effluent release point to be outside the re-stricted area boundary."
LRC Response:
Several misunderstandings need to be clarified.
- 1) The off-gas ducts from al.c 3uilding B hot cells do not run through Phase I.
The off-gas ductwork in the ceiling of Phase I services Phase 3 of Building C.
This ductwork will be removed when decontamination in Phase 3_is complete. No off-gas ducts will run through any released portion of Building C af ter the decontami-nation project is finished.
- 2) The stack and its fan room will continue to serve the Building B hot cells. Release of this area is there-fore not being sought at this time. However, LRC is seeking NRC concurrence that the excavation beneath the fan room has been decontaminated to release levels and' can be permanently refilled.
LRC recognizes that the stack and fan room must be physically isolated from all non-use areas. How this will be accomplished (e.g., moving stack or constructing a wall to isolate the fan room and stack from the inside of Building C) remains an open issue. This issue will be resolved as the license conditions for reoccupation of Buf1 ding C are clarified.
NRC Finding b:
"The background gamma radiation levels from sources outside t
of Building C may cause unmonitored personnel occupying Phase I, if it were released, to receive an exposure in excess of 500 millirem in a year (Appendix F). The licensee had not evaluated the occupancy time and potential exposures for future Building C occupants."
i LRC Response:
The primary source of extraneous gamma background in Building C is shine from the nearby Building J Annex. A lid shield has been designed and is being built for this facility.
It is expected that the gamma backgrounds will be well below the 500 mr/yr limit. This will be confirmed by surveying all of Building C, and will be reported to NRC in the Phase 3 report.
Page A-2
F NRC Finding c:
"The' licensee did not' perform any surveys in the. fire i
equipment room (room with outside entrance in extreme south-east corner of Phase I) on the basis that no licensed i
material had ever been in the room.. The only. surveys performed in the front portion of the Old Central Stores (currently ceramics area) were fifteen alpha contamination-i smears. Beta-gamma contamination and direct radiation -
surveys were performed only cn the. floor on the basis that the floor was the most'likely place to have.been contaminated in the event ~of a spill. However, Section 5.1.1 of the licensee's final survey report stated that, for the alpha surveys, 70% of the grids initially found.
above the release limit were on the walls."
[
i LRC Response:
The fire equipment room will be surveyed and reported in the Phase 3 report..See Attachment B.
Additional, random direct and removable beta / alpha. surveys i
will be performed in the' front portion' of the Old Central l
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Stores. These surveys will be done on floors and walls.
When these surveys are complete, the results will be for-warded to NRC as a supplement-to -the Phase-I report.
~
j Two more points need to be made regarding NRC finding 7.c.
NRC correctly quoted our Phase.I report as stating that 70% '
l of the initial alpha surveys above release limits were
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found on walls.
In the same paragraph, however, the report also says that this average is skewed by the-pit wall-surveys. Contamination on pit walls would occur from water l
collected in the sump or from. contaminated -liquid running off the floor and down the pit walls. This is clearly very
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different from the mechanism for contaminating a _ laboratory wall. The sump pit walls are therefore more properly -
considered part' of the floor stratum than part of the wall stratum.
If the pit walls are included in the floor stratum, 96% of the grids initially found.above release levels were floor grids, and _4% were' wall grids.
i i
Secon'dly, all surveys reading above release limits were; l
alpha surveys. Of-the -242 direct beta surveys, not one was above background. Of the 242 smearable beta surveys,'only l
one read above background. This smear exceeded background j
by 6% of the smearable beta release limit.
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The survey plan in Building C called for 100% alpha survey l
of floors, walls, and ceilings _in laboratories, and for beta surveys. of about 1/3 of floor grids..LRC concludes from the data cited in the two_ paragraphs above that this J
plan provides a sound basis for _the Building C release surveys.
Page A-3
. -._~_ _.
NRC Finding d:
"The licensee did not remove paint from surfaces containing-the original coat of paint or in areas where special nuclear material had not been. handled '(Labs 25, 26, 27, and Old Central Stores). The inspector determined.that this criteria failed-to address the potential for contaminants leaching into the painted surfaces and being masked during the scan surveys. Section 3.3 of the licensee's final.
survey report, in the third paragraph, stated _.that contamination had been found under the original coat of' epoxy paint on the floor and in the surface of the concrete -
in Lab 44 after the. final release surveys had been -
performed. The licensee did not sample other Loriginal painted areas as a result of this finding."
LRC Response:
The Lab 44 floor is not analogous to the laboratory walls.
The painted floor was inundated by a massive spill of contaminated liquid. Cleanup operations, traffic, and.
gravity would all help to drive residual contamination into the paint and.the concrete. More importantly, tha contaminated region was found during a routine re-survey of Phase I surfaces; contamination was evidenced by surveys on the painted surface before the paint was removed to reveal contamination on the concrete floor underneath. Note that as a result of this finding, all epoxy coated floors were stripped before the release survey was performed.
In discussing this issue,.it is useful to review the ba' sic survey plan used in Building C.
The approach for surveying laboratories was to alpha survey 100% of original building surfaces.
" Original building surface" means the surface or surface coating present when licensed materials were:first introduced into an area.
In some cases, this meant removing all paint (including the original coat) to reveal-the bare wall or floor. :In these cases the wall or floor.
was cleaned to the bare surface only because it would have been impractical to. remove several layers of paint and leave just the original -layer behind.
If no paint was applied on top of an original coat,' that surface was surveyed directly without paint removal. : Any areas with readings above release limits were stripped and re-surveyed. Typically, even areas with readings below release limits but above background were also decontami-nated in the interest of ALARA. This approach successfully identified the (isolated) case on the floor of Lab 44 where.
some contamination was found on the concrete.beneath the original layer of epoxy paint. There is no evidence from the subject finding.in Lab 44, from the building history, or from the survey of original paint surfaces to suggest that the approach discussed above is flawed, and that paint chip sampling on the un-stripped walls of Labs 25, 26, 27, or Old Central Stores is warranted.
Page A-4
NRC Finding e:
"As discussed in paragraph 4.d of this report, a smear reading of 1612 dpm of alpha contamination was found on the inside of a pipe in Lab 44. The possibility of residual contamination elsewhere in the pipe and its removal should be evaluated."
LRC Response:
The electrical conduit referred to here is in the wall isolating Lab 44 from the front offices.
It runs from just below the ceiling in Lab 44 to an outlet box just above the floor, and is 9-1/2 feet long. After being notified by NRC that a smear from this conduit read above background, LRC smeared the entire length of conduit. A 24 in. by 6 in, cloth was pulled through the conduit with a fish tape. The cloth was cut into pieces and each piece was counted on a gas-flow proportional smear counter. The ag yielded less than 60 dpm, or <4 dpm/100 cm2,gregate counts To supplement the above, conventional small area smears were taken at each end of the conduit. Two inch filters were used to smear the inside circumference of the conduit for a distance of about seven inches into each end. One 2
smear read 3 dpm/100 cm2, and the other read 0 dpm/100 cm,
Based on these findings, LRC does not believe removal of the conduit is necessary.
NRC Finding f:
" Soil and concrete samples collected in the U-233 process area were not analyzed by the licensee for U-233 content."
LRC Response:
Since all potentially contaminated building debris (such as concrete samples) were disposed of as radioactive waste, this comment should be directed only at the question of U-233 contamination in soil. In LRC's discussions with the NRC inspection team in November 1985, the handling of potential U-233 contamination in soil was discussed, but apparently not in enough detail to clarify how this issue was approached.
I The analytical program for assay of contaminated soil was formulated on the basis that Building C was primarily a plutonium and thorium fuels development laboratory. Large quantities of U-235 of varying enrichments were also used in numerous pregrams. The soil assay program therefore focused on finling these materials and their associated isotopes.
It was expected that because of the quantities used and its relatively high specific activity, plutonium would be the decisive contaminant in determining extent of excavation. Experience bore this out; when a ditch was
" clean" with respect to plutonium contamination,. it was also " clean" with respect to thorium and uranium contamination.
Page A-5
e Although plutonium, thorium, and natural / enriched uranium were the primary materials used in Building C, it was determined that one program using U-233 -had also been performed there. This material was -used in only one _ program over a ' span of only a few-months. The material was obtained just before the program. started, and was. shipped off site soon af ter the program' ended, so. that there was no prolonged storage in Building C.
.Thre is no historical indication of any loss or spills of this material. The amount of U-233 used (2.3 kg) was small compared to the amounts of plutonium handled in Building C.
The. limited usage of U-233 and its low specific activity compared to plutonium (U-233 has a specific activity about seven times less than the Pu-239, -240 used.in Building C) suggested that U-233 would not be a decisive ~ contaminant.in the Building C soil. Nevertheless, LRC developed a method. for assaying soil for U-233 activity and screened all release samples from Phase I for U-233 content.
The analytical method used was based on the-presence of = the U-232 impurity in U-233. The U-232 daughter used to assay _
for U-232 (and hence U-233) was Pb-212. Since Pb-212 is also a Th-232 daughter, a means was needed to distinguish:
thorium-daughter activity from U-232 daughter. activity.
This was done with Ac-228, which is a daughter of Th-232 but not of U-232. As mentioned above, all release soil samples from Phase I were screened for~ U-233_ contamination; no significant evidence of U-233 contamination was found.
I I
-J Page A-6' i
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ATTACHMENT B REVISED BUILDING C PHASE B0UNDARIES March 18, 1986
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- Soil excavation in this area is included in Phase I.
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4 ATTACHMENT C ACTION ITEMS March 18, 1986
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l ACTION ITEMS 3
NRC l
Findingl kRC Action LRC Action (a)
- 1) Certify ditch beneath fan room
- 1) Recommend disposition of as decontaminated to release stack for NRC approval by limits time Phase 3 report is issued (b)
- 1) None
- 1) Install lid shield on Bldg J Annex
- 2) None
- 2) Perform gamma surveys throughout Bldg C,
- 3) Concur (or not co'ncur) that re-3) Forward results to NRC in vised gamma levels in Bldg C are Phase 3 reporti below unrestricted levels (c)
- 1) None
- 1) Survey fire equipment room as part of Phase 3 survey
- 2) None
- 2) Perform random survey in
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old Central Stores (direct alpha, direct beta, removable alpha and beta, floors a walls)
- 3) Concur (or not concur) that
- 3) Forward, survey results ;to surfaces in old Central Stores NRC as Phase 1 report supple-are below release limits ment (by 4/15/86)
4) Evaluate LRC response for-
- 4) None warded herewith and concur or-(not concur) that beta surverys per-formed in Bldg C wepe 'a'dequate (d)
- 1) Evaluate LRC response for-
- 1) None warded herewith and cont'ur (or not concur) that strip-L z
ping of original paint sur-faces fa Labs 25, 26, 27, and old Central Stores is anwarranted 4
(e) i) Evaluate LRC response for-
- 1) None
. warded herewith and concur (or not concur) that' reference.
pipe need not be removed i:
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Page C-2
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ACTION ITEMS (Cont'd)
NRC Findingl NRC Action LRC Action (f)
- 1) Evaluate LRC response for-
- 1) None warded herewith and concur (or i
not concur) that analytical program adequately accounted for potential U-233 contamination 4
1Refers to NRC findings in Section 7 of Report No. 70-824/85-08 forwarded by 2/13/86 letter from J. Phillip,,SDjif_ to T., C.,Engelder.T G'
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