ML20036A231
| ML20036A231 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 05/04/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20036A230 | List: |
| References | |
| NUDOCS 9305100283 | |
| Download: ML20036A231 (4) | |
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Enclosure 1.-
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UNITED STATES b^
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j NUCLEAR REGULATORY. COMMISSION
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WASHINGTON, D.C. 20666-0001 o
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION-i RELATED TO ONSITE DISPOSAL OF CONTAMINATED RADI0 ACTIVE CONSTRUCTION S0ll AT THE PILGRIM NUCLEAR POWER STATION t
BOSTON EDISON COMPANY l
DOCKET NO. 50-293 i
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1.0 INTRODUCTION
By letter' dated January 15, IP93, Boston Edison Company (BEco) requested approval pursuant to Section 20.302 of Title 10 of the Code of Federal Regulations (CFR) for the disposal of'l.icensed material not previously j
considered in the Pilgrim Nuclear Power Station (PNPS) Final Environmental 1
Statement (FES), dated May 1972. The BECo request contains-a detailed description of the' licensed material-_(i.e, backfill construction soil) subject l
to this 10 CFR 20.302-request, based on.. traces of residual radioactivi.ty due to' natural fallout,- plant modification and operational / activities. :The -79,000 l
cubic feet (2,23B cubic meter) of construction soilicontainsja total radionuclides inventory of 0.636 millicuries (mci) of Cobalt-60 and. Cesium-i
- 137, i
Initssubmittal5'theBECoaddressed~specificinformation-requestedLn.
i accordance with 10 CFR.20.302(a),- provided a detailed description of:the licensed material, thoroughly analyzed and evaluated the information pertinent to the effects on the environment of the proposed disposalLof licensed 1
material, and committed to follow specific procedures to minimize the risk of unexpected exposures..
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2.0 DESCRIPTION
OF WASTf
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The material was contaminated by several events involving releases:of j
radioactive materials to onsite locations where excavations were subsequently j
made.
Theseeventswerereportedgoandinspected-bythe_, staff Some of the t*g and the~
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3 events were the Resin Earess Event, Radwaste Trucklock Soill spill from the-Condensate Demineralizer Resin' Addition Room'
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',BEco letter from E.T. Boulette to' the NRC Document Control Desk, 7
January 15,.1993.
-1 2 Licensee Event Report 82-19/032.
3' Licensee Event Report 77-29/IP.
' Licensee Event Report 88-026.
5 NRC Inspection Report 50-293/81-04.
9305100283 930504
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.' PDR. ADOCK.05000293.
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The contaminated material for disposal consists of approximately 79,000 cubic i
feet of controlled backfill grading soil placed during plant construction.
The mass of this material has been estimated to be 4.0 million kilograms.
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Four projects contributed to the majority of the material:
(1) installation of a third diesel generator; (2) 10 CFR Part 50, Appendix R fire protection modification; (3) excavation of the foundation of the hydrogen. water chemistry injection building; and (4) physical security modifications.
The material contains sand, silt, and rough stone (concrete rubble).
There are no hazardous material mixed in the soil.
3.0 PROPOSED DISPOSAL METHOD i
BECo plans to dispose of the 79,000 cubic feet of contaminated construction soil onsite pursuant to 10 CFR 20.302.
The contaminated material was moved to 1
its current. location in August 1988 to locate it further away from the we tl and. The disposal of the soil will be land application to an area located i
onsite 1200 feet south west of the plant, in an area between the Off Gas Stack access road, and the main parking lot access road within the owners controlled.
The proposed storage area is a natural depression in the ground area.
(kettle). After placement and compacting, the material will be covered with topsoil and conservation mix grass seeding to help prevent erosion.
Any remaining drainage and surface runoff will be entirely-'within the BEco own'er
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controlled area. The disposal location is approximately 150 feet from the nearest wetland, and approximately 1000 to 1500 feet from Cape Cod Bay.
The area is not.available for public use.
Upon completing the disposal, no active co.,trols will be employed since the area is within the BECo PNPS owner controlled area.
Table 1 lists the principal nuclides identified in the 4.0 million kilograms-of material.
TABLE 1 Nuclide Total Activity mci Cs-137 0.442 Co-60 0.194 Total:
0.636 4.0 RADIOLOGICAL IMPACTS 4
BECo has evaluated the' following potential exposure pathways to members of the general public from the radionuclides in the-soil:
(1) external exposure caused by groundshine from the disposal site; (2) internal exposure caused by i
inhalation of re-suspended radionuclides; and (3) internal exposure from ingesting ground water.
The ' staff has reviewed BECo's calculational methods and assumptions and find that they are acceptable.
The dose assessments are-based on the following:
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- 1. 0.636 mci of contaminated construction soil distributed over 79,000 square feet.
- 2. Direct radiation exposure of 2000. hours per year.
- 3. Inhalation exposure based on 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> per year is minimized due to 6-inch layer of gravel (which inhibits wind erosion).
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- 4. Groundwater not considered because there are.no domestic wells in the area down-gradient from the plant.
j Doses calculated from these pathways are shown in Table 2.
The total dose of 0.075 is within the staff's guideline of 1 mrem per year.
Such a dose is a
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small fraction of the 300 mrem received annually by members of the general public from sources of natural background.
t TABLE 2 i
Whole Body Dose Received.
by Maximally Exposed. Individual Pathway (mrem /vr)
Groundshine 0.025 Inhalation 0.050 Groundwater Ingestion
'0.000 Total 0.075 The guidelines used by the NRC staff for onsite disposal of licensed material are presented in Table 3, along with the staff's evaluation of how each guidelines has-been satisfied.
BEco's procedures and commitments as documented in the submittal are acceptable, provided that they are permanently incorporated into BECo's Offsite Dose Calculation Manual (0DCM) as an Appendix, and that future.
I modifications be reported to NRC in accordance with the applicable ODCM change protocol.
Based on the above findings, the staff finds BECo's proposal to dispose' of the ~
low level radioactive waste soil onsite in the manner described in the BECo letter dated January 15, 1993, to be acceptable.
t Principal Contributor:
J. Minns
.Date:
April 26, 1993 k
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"20.302TGUIDELINE FORl LSTAFF'S EVALUATION!
tONSITE DISPOSAE l.
The radioactive material 1.
Due to the nature of the should be disposed of in a disposed material, recycling to manner that it is unlikely that the general public is not i
the material would be recycled, considered likely.
i 2.
Doses to the total body'and any 2.
This guideline is addressed in body organ of a minimally Table 2.
exposed individuals ( a member of the general public or a' non-occupationally exposed worker) from the probable pathways of exposure to the disposed material should be less than 1 mrem / year 3.
Doses to the total body and.any 3.
Because the material will be body organ of an inadvertent land-spread,.the staff intruder from the probable considers the maximally exposed pathways of exposure should be individual scenario to also i
less than 5 mrem / year.
address the intruder scenario.
r 4.
Doses to the total body and any 4.
Even-if recycling were to occur j
body organ of an individual after release from regulatory
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from assumed recycling of the control, the dose to maximally.
3 disposed material at the time exposed member of the public is
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the disposal site is released not expected to exceed 1 f
from regulatory control from mrem / year, based on exposure-i all likely pathways of exposure scenarios considered inLthis 3
should be less than 1 mrem, analysis.
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