ML19347C829
| ML19347C829 | |
| Person / Time | |
|---|---|
| Site: | Wood River Junction |
| Issue date: | 02/17/1981 |
| From: | Shum E NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Orton C RHODE ISLAND, STATE OF |
| References | |
| NUDOCS 8103060517 | |
| Download: ML19347C829 (4) | |
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FEB 171981 Distr:
Docket 70-820 rm ElHF
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DCS Dr. Colin G. Orton GPage FCUF EE Vice Chairman WTCrow M
Rhode Island State Radiath,n Comission RWi?de
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Rhode Island Hospital RStevenson E.-5 Department of Radiation Oncology
=pEShum g24 Eddy Street
.LTyson G
Providence, Rhode Island S290%
PMagno(EPA) e JEHickey (Rhode Island Dept.
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Dear Dr. Orton:
of Rad. Health)
E=d Thank you very much for your letter dated December 29, 1980, conennting m='
on the NRC's draft " Proposed Soil Decontamination Criteria," forAe
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decommissioning of the United Nuclear Corporation's facility at Wood River
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Junction, Rhode Island. The following are discussions and responses to your conments with regard to (1) NRC's proposed radim criteria, (2) health
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m risk on inhalation of radon and-its decay products, and (3) parameters used
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1.
NRC's Proposed 3 pC1/g Ra-226 Soil Limit
.' ra.P The roposed 3 pCi/g Ra-226 soil limit for open land cleanup at the UNC site represents the target criteria consistent with the criteria iff currently established by EPA for similar-type situations. The EPA's J:2 interim standard for Ra-226 contaminated land is 5 pC1/g Ra-226,
.L including background. The NRC's proposed limit does not include EZ background. The background concentrations of uranius, obtained from the e'
licensee's (UNC) preliminary preoperatior:al data, indicate that the 3
Ra-226 concentration (assuning uraniun and radiun are in secular equilibriun) at the UNC site is rather low (i pC1/g Ra-226). Therefore, l
=W the total limit is expected tu be at or less than 4 pC1/g Ra-226. As Z
stated in the Federal Register (Vol. 45 No. 79 April 22,1980), the proposed cleanup criteria of 5 pC1/g Ra-226 is EPA's judgaent of the
- =d most stringent uniform cleanup condition that may reasona51y be required for all the inactive mill sites. According to EPA, lowerhg the standard 95 to less than 5 pC1/g would provide very little gain in health protection, 2'
since such slightly contaminated soil is psually thin layers containing little total radium. (This situation should apply to the UNC site.)
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5 is also noted that radfun level in soil in some areas in the United G
States could be as high as 3 pCi/g; therefore, lowering the soil limit e
of Ra-226 to less than 3 pCf/g is judged by the staff not to be cost-EZ,j effective for open land cleanup action.
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w In regard to your comment that the EPA's standard should only apply to Western U.S. and may not be applicable to the State of Rhode Island, Is
'ZT it is our understanding that the interim standard,,is intended for the m.._ _.
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Dr. Colin G. Orton j
2-FEB 171981 uranium processing sites not* only located at Westem U.S., but also sites at Eastern States, such as Canonsburg, Pennsylvania, or any sites in the United States 2.
. Health Risk Estimates for Radon and Its Decay Products for the General Public In connection with the Environmental Protection Agency (EPA) issuance of interim standards for cl?anup of open land and buildings contan:Inated with residual radioactive materials from inactive uranium pmcassing sites as specified in 45 Federal Register, 27370 (Ap:-il 22,1980), a Draft Environmental Impact Statement (DEIS) was issued (EPA Docket No. A-7925) in support of the proposed EPA interim standard.
In the DEIS, EPA, using a " life table" analysis and an absolute risk model, estimated a 1 x 10-4 chance of fatal luag cancer per year over a lifetime for each year of continuous exposure to radon and its daughters of 0.01 working level (WL (see Chapter 4 of DEIS). To estimate lifetime rick of fatal cancer cause)d by 0.01 WL and lifetiree exposure 75 of the time, the percent of the exposure that will result in fatal cancer is equal to 1 x 10' x 70.7 (0.75) x 100% = 0.5%.
This is the derived nisnber shown in Table 1 (A) in the above-mentioned Federal Register. Siailarly, for a 0.006 WL and lifetime exposure 75 percent of the time, the percent of the exposure that will result in fatal cancer will be 0.006/0.01 x 0.5 = 0.3%.
In comparison with the total national lung cancer mortality of 2900 per 100,000 or 2.4% in a stationary population from the 1970 mortality rate, this represents 10% of the total national lung cancer mortali ty. This is a factor of 5 and 60 less than your estimation in items (b) and (c) of your letter.
If the comparison is made with the overall cancer n.srtality in the United States of about 19.8% based on 1976 data (American Cancer Society - Cancer Facts & Figures,1979), this represents g.3 G
x 100% = 1.5% of the total natiox#. cancer mortality.
In your letter, item (d), you indicated that the calculation of radon risk may be under-e.stimated because the mine atmospheres and indoor residential atmosphere
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may not be couparable. On the other hand, as pointed out by EPA in their document on " Indoor Radiation Exposure due to Radium-226 in Floridas Phosphate Lands - EPA 5204-78-013, February 1979," that miner's lung cancer mortality data reflect a hiah frequency of cigarette smuking which tends to increase their lung cancer risk relative to the general population; this will tend to overestimate the risk. All these are t
among the other uncertainties in the radon risk estimates discussed in the above EPA document.
3.
Parameters Used for Calculating Indoor Radon Level As pointed out in our " Staff Technical Position for Interim Land Cleanup Criteria for Uranium Mill Sitqs," the calculations of working level (WL) concentrations inside a structure from rado1-222 entering the structure
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Dr. Colin G. Orton.
FEB 17 198f showed a very wide range of concentrations influenced by many couplex factors. Therufore, an average value based on midpoint of the range of input parameters was listed. The average value derived can be-compared with current measurement conducted by George and Breslin.I In Geon.;e and Breslin's study, the concentration of radon and radon i
daughters in 21 New Jersey and New York residences was investigated.
The residences we?e either of brick or wood frame construction and were nonnal single-family dwellings.
The investigation consisted of a series of one-week time integrated measurement of both radon concen-trations and " working levels" of radon daughters, conducted over a i
two-year period to yield annual mean levels. The following is a sunmary of the findings:
Radon Concentrations Heasured By
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George and Breslin Annual Averages Location Picocuries/ Liter Working Level Range Geanetric Mean Range Geometric Mean Cellar
.34-4.4 1.7
.0017.026
.0081 First Floor *
.25-3.1
.83
.0017.013
.0041 Outdoors
.11.34
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.0009.0529
.0016 Radiun Concentration' - Mean 1.0 pCi/gm
- Measurement of radon levels on sected floor yields no significant difference from first floor measurement.
If the first or second floor radon levels are used as a reference for normal average living conditions,then our calculated average value appears to be in good agreement with the measured values (within a factor of 2).
(It is noted that the above measurtments not only included the radon contribution from soil, but also included radon contribution from water and maybe from natural gas used in home.) However, under certain situations anc:
parameters used, tia calculated working levels with a given soil concen-tration could vary substantially. Therefore, ir order to demonstrate compliance on open land cleanup, it is better to set criteria based on radiun concentration in soil.
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IA.C. George and A.J. Breslin - The Distribution of Anbient Radon and ' Radon Daughters in Residential Buildings in the New Jersey-New York area - presented. p' at the 00E/UT Symposiun on the Natural Radiation Environment III, Houston, s
l Texas, April 23-28, 1978.
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Dr. Colin G. Orton FEB 171981 The following provides additional answers to your several questions on specific parameters used for the calculation of radon working levels.
2 is in the range of The ayerage ven;11ation rate for American homes a.
could be 0.2 - 0.3 hr p-' (x) and for a very well insulated home 1 hr-' tu 2 h g
3 b.
For concrete floor, the B value used is 0.05-0.2 ; for cracked concrete, the B value used is 0.2-0.5.
c.
The dose conversion factor of 5 rem per WLM was from the BEIR-II report; the current dose conversion factor in the BEIR-III report is 6 rem per WLM which is not significantly diffemnt from that given in the BEIR-II report.
In addition, we do not expect that there will be a serious problen due to Ra-226 contamination in soil at the UNC site since only a trace quantity of Ra-226 (the concentration of Ra-226 in lagoon liquid is less than the EPA's drinking water standard) is fotmd in the lagoon liquid effluent.
We hope you find our responses to your questions satisfactory. If you
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have additional questions in regard to our proposed criteria, please feel free to write us.
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Sincerely,g original si
[18084 g E. Y. Shum Uranium Process Licensing Section Uranium Fuel Licensing Branch Division of Fuel Cycle and Material Safety
'-.s 2Handley, T.H. and Barton, C.J., Home Ventilation Rates: A Literature Survey, ORNL-TM-4318 (1973) 3Culot, M.V.J., Olson, H.G. and Schiager, K.J.,1973 Radon Pmgeny Control in Buildings. Final report on research supported by EPA and AEC.
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