ML20210Q699
| ML20210Q699 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 04/29/1986 |
| From: | Zwolinski J Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20210Q687 | List: |
| References | |
| NUDOCS 8605140223 | |
| Download: ML20210Q699 (6) | |
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7590-01 UNITED STATES NUCLEAR REGULATORY COMMISSION CONSUMERS POWER COMPANY DOCKET NO. 50-155
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ENVIRONMENTAL ASSESSMENT AND FINDING OF NO SIGNIFICANT IMPACT The U.S. Nuclear Regulatory Commission (the Comission) is considering the approval of disposal of approximately 5300 cubic feet of contaminated soil by leaving it in place proposed by Consumers Power Company (the licensee) for the Pia Rock Point Plant, located in Charlevoix County, Michigan.
ENVIRONMENTAL ASSESSMENT Identification of Proonsed Action: The proposed action by the NRC would acprove the disposal of contaminated soil by leaving it in place at the facility, as proposed by the licensee's request dated August 16, 1985. The request for aooroval is submitted pursuant to 10 CFR 20.302. The total volume of contaminated soil is estimated to be 5300 cubic feet.
The Need for the Proposed Action: In May of 1984, soil underneath the turbine buildina was contaminated by a leak of condensate from a 2-inch diameter aluminum Dipe also located under the floor of the turbine building.
The pipe normally carries condensate to the condensate storage tank.
Approximately 3x10-3Ci of Co-60, Mn-54, Cs-134 and Cs-137, plus shorter-lived radionuclides, may have been released into the soil. After removal of eicht 55-gallon drums of contaminated soil, and reduction by radioactive decay, the quantities remaining as of July 1985 are estimated by the licensee to be about 7x10-6Ci of Co-60, 2x10-5C1 of Mn-54,1.1x10-sci of Cs-134 and 1.0x10-5Ci of Cs-137, totalling about 3x10-5C1.-
Environmental Impacts of the Proposed Action: In the attachment to the letter of August 16, 1985, the licensee provided information on the geology and hydrology of the area, on behavior of currents in the adjacent waters of 8605140223 860508 DR ADOCK O QS
7590-01 Lake Michigan, and on the soil sampling done to determine the extent of the contamination. The licensee also provided an assessment of the potential radiological impacts of leaving the soil in place.
The staff has reviewed the information submitted by the licensee.
Considering the size of storage tanks involved and measured concentrations of radionuclides, the staff .iudges that the licensee's estimates of the quantity of water and the quantities of radionuclides leaked to the soil are reasonable but sub,iect to some uncertainty. The analyses of soil samples show that the concentrations of radionuclides remaining in the soil are small. The staff
.iudges the licensee's estimates of the volume of soil contaminated and of the total quantities of radionuclides remaining in the soil to be only approximate.
However, based on review of the submitted information on the site geology and hydrology and the results of soil samplino, the staff considers the concentrations of radionuclides in the soil and the potential extent of the soil contamination to be adeouately defined.
The staff has evaluated the impacts of-leaving the contaminated soil in place, and finds that the potential envirnnmental impacts are insignificant.
For conservatism, the staff based its estimates of doses from the soil on the radioactivity concentrations in the soil at the sampling point (outside of theexcavatedarea)showingthehkghestconcentrationsofcontamination.
The average concentrations of the significant radionuclides at this location, with some correction for backgroupd, are:
Mn-54 2.5 x 10~ Ci/m33 2.6x10jl Ci/g3 Co-60 3.2 x 10~ Ci/m3 7.3 x 10~ C1/m 3 Cs-134 2.0 x 10~ Ci/m3 4.3 x 10-8 Ci/m Cs-137 2.4 x 10~ Ci/m 1.9 x 10~ C1/m 3 3 5.0 x 10-6 Ci/m
- 2.0 x 10-6 Ci/m *
(July 10, 1984) (10 years from now)
- Forcomparison,radioactigeK-4 occurs naturally in soil at an average concentration of 1.6 x 10~ Ci/m
l 7590-01 For its estimates of the potential impacts of any release of the J radioactivity to the waters of Lake Michigan, the staff used the licensee's 1 ostimate of the total quantities leaked. The total quantities of the more important radionuclides leaked were estimated by the licensee to be, as of May 30, 1984:
Mn-54 1.30 x 10- Ci Co-60 2.40 x 10- C1 Cs-134 1.22 x 10- Ci Cs-137 1.74 x 10- Ci 3.33 x 10-3 Ci Results of the staff's evaluation of the impacts are provided in Table 1.
Table 1. Potential Impacts of Leaving the Soil in Place Estimated Occupational Radiation Exoosure a Dose Rate Workina above the contaminated soil, 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> / year 1.0 mrem Working in a hole in the soil, per week b Inhalation of contaminated dust, dose to the lung, per year c Potential Exposure of the Public Living above the contaminated soil, per year b, d Eating vegetables grown in the soil, per year c, d Shoreline recreation e Eating fish e Drinking water e a = All doses are radiation dose to the total body of an individual unless otherwise specified. Dose estimates are primarily based on the methodology of ti.S. NRC Regulatory Guide 1.109, Rev. 1, and on the concentrations of radionuclides in the soil at the maximum sampling point outside the excavated area, b = Less than 1.0 mrem.
t = Less than 0.1 mrem.
d = With 10 more years' radioactive decay, but no further removal by groundwater.
transport or other processes, e = less than 0.1 mrem to any individual if all leaked quantities were released to Lake Michigan at once; release by groundwater transport through the soil will result in smaller doses.
e 7590-01
.4-These results show that exposure rates due to leaving the contaminated soil in place are 1
at most only about 3 mrem per year to the total body. For perspective, the l radiation from the naturally occurring radionuclides in soils and rocks plus I cosmic radiation give a person in Michican a whole-body dose rate of about 89 mrem per year outdoors, which may be altered as much as 20 mrem per year by the type of construction of the person's residence (e.g., wood frame or brick) and the amount of time spent in it. The staff's estimate of about 3 mrem per year is highly conservative because the soil sampling indicates that at most only a i
few hundred square feet are so highly contaminated, and that most of the {
contamination is at depths where the overlying soil and concrete would shield people from the radioactivity more e#fectively than is assumed in the staff's calculations. It is unlikely that a member of the general public would be exposed to the contaminated soil until after the plant decommissioning, 10 years or more in the future, since most of the contaminated soil is located under the turbine buildino. The staff's estimates of potential exposures from release of the contamination to the waters of Lake Michigan are conservative because they are based on the modeling assumption of an instantaneous release of all the leaked cuantities (as of May 30, 1984) of radionuclides into Lake Michigan, with no allowance for the retention of contamination in the soil which is evidenced by the results of analysis of soil samples.
With regard to the nonradiological impacts, the staff iudges that leaving the soil in place has the smallest impact.
Based on our review and evaluation of the proposed disposal, we find that:
(1) The radiation exposures to the nuclear station workers involved in the
[ disposal are small compared to the routine occupational exposures at the Big Rock Point Plant.
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! 7590-01 i (2) The possible radiation. risks to members of the general public as a result of such disposal are well below regulatory limits and small in comparison to the doses they receive each year from natural background radiation.
(3) The nonradioloaical environmental impacts of the proposed procedure are minor.
Alternatives to the Proposed Action: The princiral alternative to leaving the contaminated soil in place would be to dig it up, packaoe it in 55-gallon l drums or other suitable containers and ship it to a disposal facility licensed to t
dispose of low level radioactive waste. This would be costly, requirino, for g
examole, the shiopino of more than 700 S5-gallon drums. It could also require the disruption of the overlyino turbine building. On the basis of the.above analysis and evaluations and after weighing the environmental, technical, and other benefit against the environmental costs, the staff concludes that the action called for under NEPA and 10 CFR Part 51 is the issuance of an approval of the oroposed waste disposal procedure.
- Alternative Use of Resources
- The principal result of this action does involve the use of resources beyond the scope used during nomal plant oper'tions; however, this new use of land is not significant, as the land involved is located, and will remain in place, underneath the floor of the turbine building. This
! action involves no other critical materials or resources.
Aoencies and Persons Consulted: The Consnission's staff reviewed the licensee's request and has not consulted other agencies or persons.
FINDING OF NO SIGNIFICANT IMPACT The Consnission has determined not to prepare an environmental impact statement for the proposed action.
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7590-01 Based upon the foregoing environmental assessment, the Commission concludes that the proposed action will not havt a significant effect on the cuality of the human environment.
For further details with respect to this action, see the licensee's request for approval dated August 16, 1985, which is available for public inspection at the Commission's Public Document Room, 1717 H Street, N. W., Washington, D. C.
20555 and at North Central Michigan College,1515 Harvard Street, Petosky, Michigan 49770.
Dated at Bethesda, Maryland, this 29th day of April 1986.
FORTHENilCLEARREGULAkbR(00 ISSION
$g John . Zwolinski, Director BWR P .iect Directorate #1 Divisi n of BWR Licensing Office of Nuclear Reactor Regulation
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