ML20135C748
| ML20135C748 | |
| Person / Time | |
|---|---|
| Issue date: | 02/21/1997 |
| From: | Joseph Holonich NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Sena R ENERGY, DEPT. OF |
| References | |
| REF-WM-39 NUDOCS 9703040260 | |
| Download: ML20135C748 (8) | |
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NUCLEAR REGULATORY COMMISSION
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i i 1 Mr. Richard Sena, Acting Director Environmental Restoration Division
!y Uranium Mill Tailings Remedial Action Project i !
U.S. Department of Energy 2155 Louisiana NE,' Suite 4000 l4 Albuquerque, NM 87110 i
SUBJECT:
STAFF TECHNICAL EVALUATION OF THE SALT LAKE CITY VITRO PROCESSING
. SITE AND VICINITY PROPERTY (SL-0675) COMPLETION REPORTS i
Dear Mr. Sena:
The U.S. Nuclear Regulatory Commission staff has reviewed the U.S. Department of Energy (DOE) response to NRC comments and the revised completion reports for the Vitro processing site and vicinity property SL-0675 in Salt Lake City,
-Utah, submitted August 13 and August 15, 1996.
Based on review of these submittals, th NRC staff is unable to concur that the U.S. Environmental
' Protection A6tacy (EPA) standards have been met at the Vitro processing site.
a A complete discussion of the issues is provided in Enclosure 1.
The NRC staff i
does concur that the vicinity property SL-0675 meets the applicable standards (see Enclosure 2).
In general, DOE needs to demonstrate that the Uranium Mill Tailings Remedial Action Project has provided for the long-term protection of public health and safety at the Vitro site. To do this, DOE needs to provide some mechanism to
.j; ensure that future owners of the property are aware of the location and amount of excess radioactive material at the Vitro site. DOE's commitment to provide this information to only the present land owner and the State does not accomplish this. The DOE land annotation rule could require that such y,
inforination become part of the public record, or require reference and access to the completion report. DOE could also add the processing site post-1 remedial data to the supplemental standards database to track remaining contamination, as described in the DOE letters of May 9 and August 23, 1995.
For that data to be useful, DOE should ensure that the information in the t
database is easily accessible to the public.
In addition, DOE could provide a \\ {
l revised Vitro Post-Remedial Action Status Report to the city / county department 1
that controls building' permits. NRC staff also requests information relative (JDI$
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to how the State of Utah proposes to fulfill its responsibility under subsection 104 (d) of the Uranium Mill Tailings Radiation Control Act.
If you have any questions, please contact the NRC roject Manager, Elaine Brummett at (301) 415-6606.
Sincerely, (Original signed by)
Joseph J. Holonich, Chief Uranium Recovery Branch i
Division of Waste Management Office of Nuclear Material Safety
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and Safeguards
Enclosures:
As stated l
cc:
L. Fahey, DOE Hqts S. Arp, DOE Alb S. Hamp, DOE Alb J. Virgona, DOE GJP0 l
E. Artiglia, TAC Alb l
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TECHNICAL EVALUATION OF THE U.S. DEPARTMENT OF ENERGY'S RESPONSE TO ISSUES ON THE COMPLETION REPORT FOR THE UMTRA PROJECT VITRO PROCESSING SITE i
SALT LAKE CITY, UTAH By letter dated August 13, 1996, the U.S. Department of Energy (DOE) provided page changes to the Vitro Processing Site Completion Report'(CR) and responses to U.S. Nuclear Regulatory Commission comments of May 9, 1996.
Based on l
review of this submittal, the NRC staff concludes that additional information is required. The evaluation of issues is provided below.
ISSUE Ic: Missing Radiological Verification Data i
- 1) provide evidence that adequate gamma data was obtained for all grids on the site (except the four under the influent collection box) that do not have Ra-226 data in the CR; j
- 4) explain why some grids in the Section 7 tables have both " actual" and
" calculated" Ra-226 values.
DISCUSSION:
(1) DOE modified the last paragraph on CR page 5-6 to indicate that delta measurements were used to guide excavation and that if collection
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of a soil sample was not practical, these measurewnts were used for l
verification purposes. NRC staff does not approve of delta gamma measurement I
as a method of providing verification data because of the imprecise nature of the measurement and because DOE did not provide data establishing a correlation of Ra-226 values and delta readings. However, given the limited use of this type of measurement in lieu of Ra-226 data (9 grids), staff considers that the Ra-226 values should approximate the required levels.
(4) DOE's last sentence in response 4 indicates that it is reasonable to assume that the calculated Ra-226 value (average of adjoining grids) is a valid number for the grids where the OCS value exceeded the EPA standards.
The staff disagrees with this statement. There-is sufficient data in the UMTRA Project files to show that spotty contamination remains after the first excavation has been conducted and Ra-226 values of adjacent grids would not necessarily reflect the level in a particular grid. Given that CR page 7-5 states that at least six inches of backfill was placed in all excavated areas, only the six grids identified in Issue 2 exceed the subsurface standard by actual measurement. However, the first sentence, fourth paragraph of page 7-1 i
says that only the 5 pC1/g standard is applicable for the Vitro site.
The staff also noted that revised Table 7.1 lists 22 grids without actual Ra-226 data, but 12 of these appear on the maps to be partial grids and I grid is under the influent box.
STATUS: NRC staff accepts the CR page changes provided in response to Issue 1, but page 7-1 apparently contains an error.
Points of NRC disagreement with DOE statements are noted above. This issue is closed.
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l ISSUE 2:
Six Grids Exceed the Ra-226 Subsurface Limit DOE had indicated that the six highest Ra-226 values are bookkeeping anomalies reflecting a failure to update records to include the final verification sample analysis and that resample certification was lost for the grid that had a laboratory analysis of 28 pCi/g.- NRC staff indicated that if the missing final verification data can't be found, one approach for closing this issue is cleanup of the two grids with the highest Ra-226 levels as the others should not present a potential health hazard, based on conclusions made for other sites. Another approach is for DOE to work with the city / county / state to institute land use restrictions or land annotation, if the location and concentration i
of the remaining contamination is included in the documentation.
DISCUSSION: DOE agreed to consider the six grids as not meeting the EPA radbm.(Ra-226) cleanup criteria, but did not choose any of the suggested options for closing the issue.
Instead, DOE developed a Post-Remedial Action Status Report, including a map indicating the location of the six grids and a health risk analysis, that will be sent to the state and current property
'j owner. The report and revised CR page 7-6 conclude that the grid with 42 pCi/g Ra-226 could produce 0.02 WL in a house built over that area, but do not indicate if the radon flux was calculated assuming that 4.7 feet of backfill would remain in place for 1000 years. Also, neither document indicates that the Uranium Mill Tailings Remedh1 Action (UMTRA) Project WL limit for existing buildings is 0.02 WL (40 CFR 192.12(b)). NRC staff dose modeling using the RESRAD code, resulted in potential doses greater than 100 ares /yr, depending on the year and the amount of cover assumed to remaia.
Radon flux modeling, assuming one foot of cover over six inches of soil containing 42 pCi/g Ra-226, indicated an interior radon progeny concentration of 0.03 WL could result. Although this estimate exceeds the limit, staff realizes that the grid with elevated radium is surrounded by areas with radium below the standard and that building a habitable structure directly over this one 100 m area is unlikely. Therefore, staff concludes that of the six 8
verification girds not meeting the 15 pCi/g plus background radium standard, only the one with the highest concentration could potentially produce an unacceptable health risk under certain, but unlikely conditions.
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DOE's response also indicated that the disparate laboratory values- (23.1 versus 3.9 and 3.1 versus 50.0 pCi/g) probably are the result of aliquot i
differences and that the OCS value is the value to use.
Staff considers this a possible explanation, but some follow-up should have been done at the time the data was reviewed by the State of Utah.
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STATUS: DOE should revise the Vitro status report and CR page 7-6 to indicate the backfill depth assumed for the flux modeling, the potential consequences i
and radon mitigation procedures if a habitable structure is built on the deposit with minimal intervening fill, and that the UMTRA Project WL limit is 0.02 WL. Also, because the highest radium value could increase the potential health risk under certain conditions, staff recommends that DOE take steps to enable future owners of the property to be aware of this residual contamination.
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ISSUE 3f: Elevated Th-230 RAP MOD 4 indicates that the projected radon flux from the two areas of Th-230 contamination is low,....
This issue is open until the supplemental standard application for Th-230 in the saturated zone i
includes sufficient justification to demonstrate that the potential long-term health risk due to the Th-230 is acceptable.
BACKGROUND: DOE should be aware that NRC staff raised the issue of the 1000-year Ra-226 level due to decay of excess Th-230, as ea;rly as 1983 for the j
Canonsburg site (letter to the Uranium Nill Tailings Project Office Project Manager, dated September 15,1983).
If the State of Utah had been'made aware of this concern, or if the NRC had been provided with the supplemental standard application for Th-230 before the last tailings were removed from the 1
Vitro site (November 1987), this issue may have been easier to resolve. Also, NRC acceptance of the DOE UMTRA Project policy on Th-230 (July 5,1994) was
- contingent upon additional measures to reduce Th-230 to as low as reasonably 1
achievable (ALARA). NRC recommended health risk analysis, considering all j
residual contamination, because the 35 pCi/g level, or unlimited Th 230 in the water table is not protective of human health under all reasonably possible situations. DOE should not assume that 35 pC1/g Th-230 is always ALARA because other federal programs require cleanup to as lou as 5 pCi/g.
MEETING THE EPA STANDARD: The revised CR Sectic;i 6 only mentions the 35 pCi/g j
standard for Th-230, and does not indicate how leaving Th-230 levels to l
650 pCi/g complies with 40 CFR 192.22 (b), i.e., levels reduced to as low as j
reasonably achievable (ALARA). The top of page 6-7 does indicate that the elevated Th-230 levels are assumed to be in areas where excavation extended to
'the water table, but does not indicate why higher levels of Th-230 in the water table is acceptable and what, if any, level is not acceptable.
In contrast, the March 1995 CR (pages 6-5 to 6-7) discussed compliance with the EPA standards, indicating that leaving the thorium in saturated soil (suppresses radon emission) would result in insignificant present and future hazards and, therefore, the costs of excavation and transport of the materials were not justified.
If DOE has documentation that all the elevated thorium grids were excavated to the water table (saturated soil), and the water table is likely to remain stable long-term, this needs to be discussed as supporting the ALARA determination. Such documentation seems unlikely because CR Table 6.1 indicates that one grid with 400 pCi/g Th-230, had 6 inches of backfill while nearby grids in Area 3 had 2 to 5 feet of backfill.
The ALARA determination should also include justification of the amount of backfill used in the dose or radon flux modeling as the amount likely to remain in place long-term.
In' revised CC Table 6.1, the last column indicates the potential ~ radon flux (not WL as stated in the response), in a 1000 years, from each grid with known elevated Th-230. DOE considers that a radon flux of 3.9 pC1/m's could result in a radon progeny level of 0.02 WL in a house built over that area. The table indicates that Th-230 contamination in 20 of the 24 grids could cause radon progeny concentrations that exceed the recommended levei. The staff notes that the flux modeling includes backfill depths up to 3
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l 8.5 feet, but maintenance of the current backfill depth for 1000 years cannot be assumed in areas to be released for unrestricted use.
I The staff noted that neither revised CR page 6-4 nor 6-8 indicate that the UMTRA Project WL limit for structures is 0.02 WL. Also, DOE compared its calculated dose levels to the probably background radiation level (400 mren/yr), but failed to mention the 100 mres/yr dose limit to the public.
L Page 6-9 of the revised CR contains Table 6.2 indicating that the dose (in l
1000 years) for-people working in buildings built over the saturated Th-230 material could result in 83 to 2119 mren/yr (assuming backfill depths of 0 to 6 feet). The NRC staff performed dose modeling using the RESRAD code.
Depending on the amount of cover assumed to be present and the thorium level, the potential dose within the next 1000 years varied from 45 to 2400 mren/yr, i
mainly from radon.
Given the proposed land use for expansion of the water treatment facility, there is little health risk. However, if an office
!- a building were placed on a thorium deposit, or if the thorium material was excavated and placed on another property, the contaminnion could result in an unacceptable health risk, during the next 1000 years. This risk, primarily due to radon would increase if the water table were to be lowered, as is i
likely given current water use trends.
An additional concern that is mentioned ir, the CR, is that soil from the most likely areas for elevated Th-230 was analyzed, but the deposits were not i
delineated. Therefore, probably many more than 24 grids contain elevated Th-230. The staff also noted that data in CR Appendix B indicates some Th-230 values of <50 pCi/g, so there could be additional areas with elevated Th-230.
PROTECTING THE PUBLIC: The long-term potential health risk from Th-230 and its decay products could be controlled, depending on how DOE implements the UMTRA Project land annotation. The Uranium Mill Tailings Radiation Control i
Act, Section 104(d), states.that the DOE "... shall issue appropriate rules and regulations to require notice in the local land records of the residual radioactive materials which were located at any processing site..."
It also indicates that the State shall take action to notify any person, prior to purchase of the site, of the condition of such site after remedial action.
Therefore, the NRC staff considers it appropriate for DOE and the State to provide a mechanism that allows future owners of the site to know where the deposits are and to know that potential health risks due to the residual material can be avoided.
STATUS: This issue will be closed when the CR is revised to demonstrate that the elevated Th-230 remaining on site is in compliance with the EPA standards.
Alternatively, since a convincing ALARA determination for the Th-230 is unlikely, DOE should demonstrate that long-term protection of the public health will be provided for in the land annotation rule.
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f TECHNICAL EVALUATION OF THE VICINITY PROPERTY COMPLETION REPORT FOR SL-067S CENTRAL VALLEY WATER RECLAMATION FACILITY SALT LAKE CITY, UTAH BACKGROUND:
NRC concurrence is required in the Completion Report (CR) for Vicinity Property-(VP) SL-067S because supplemental standards (leaving residual radioactive material) were applied to three distribution boxes that were not identified in the Radiological Engineering Assessment. The VP is owned and occupied by a municipal sewage treatment operation, the Central Valley Water R9clamation Facility.
On September 13, 1995, NRC staff provided comments (open issues) concerning the April 1995 version of the VP CR for this property and DOE provided a revised CR December 5, 1995. The results of our review of the revised CR were submitted May 9, 1996.
DOE provided a revised CR and response to comments by letter dated August 15, 1996.
Staff review of these documents has resulted in the determination that one issue was not fully addressed.
ISSUE 5: DOE should provide the property owner with an updated map indicating all grid areas included in the application of supplemental standards. DOE also should ensure that land annotation for this property will include locations, quantity, and concentration of remaining contamination and that this information is easily accessible to the public.
DISCUSSION:
DOE indicated that a copy of _the VP CR will be sent to the state and current property owner, but the portion of the issue on land annotation cannot be addressed until DOE issues the final rule on land annotation.
However, DOE has agreed (May 9,'1995) to prepare a database to track contamination remaining on VPs due to the application of supplemental standards.
STATUS: Staff recommends that DOE take steps to make the information in the supplemental standards database accessible to the public and provide access to the completion report via the land annotation rule. This issue is closed and the signed NRC Review Form is attached.
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VP No.: SL-067 NRC Review Form for Supplemental Certification of Vicinity Properties The Department of Energy (DOE) has determined that the remedial action at the following vicinity property (VP) has been completed and thereby complies with supplemental standarris invoked by DOE under 40 CFR, Subpart C, specifically Subsections 192.21 and 192.22.
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NRC concurrence for the Radiological Engineering Assessment (REA) was given on:
Santember 25,1985 j
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Supplemental standards were not in the REA, special circumstances required that i
als ds be involved during remedial action.
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/-23-97 Gaeton Falance, DOE Certification Officer Date l
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Based on the information and certification provided by the DOE, the NRC:
1 concurs that the remedial action at the subject VP has been completed under its authority provided by the Uranium Mill Tailings Radiation Control Act (UMTRCA), Section i
104(f)(1) and as described in the Memorandum of Understanding (MOU), Appendix A, Section 3.4.
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concurs, as above, except for the following conditions:
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[ } See attached sheets for any additional provisions.
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needs additional information to make a concurrence decision. This information consists of:
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[ ] See attached sheets for any additional informational needs.
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NRC Concumng Official and Title Date
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