ML19347E728
| ML19347E728 | |
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|---|---|
| Site: | Crane  |
| Issue date: | 05/11/1981 |
| From: | Office of Nuclear Reactor Regulation |
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| NUDOCS 8105130278 | |
| Download: ML19347E728 (21) | |
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SUPPLEMENT TO THE ENVIRONMENTAL IM?ACT APPRAISAL BY THE DIVISION OF ENGINEERING EVALUATING THE PROPOSED RESTART OF_
THREE MILE ISLAND NUCLEAR STATION, UNIT 1 DOCKET NO. 50-289 An Enhironmental Impact Appraisal (EIA) relating to the proposed restart of Three Mile Island, Unit I was issued by the NRC Staff in March 1981.
In a motion filed by Intervenor Steven C. Sholly "To Reject the NRC Staff Environ-mental Impact Appraisal on TMI-l Restart or in the Alternative to Seek Leave from the Board to Raise New Contentions" (April 9,1981) and in the Commonwealth of Pennsylhania's response to that motion (April 22,1981), certain deficiencies in the EIA were alleged.
As set forth in the NRC staff's response ;o the Commonwealth (May 11, 1981), certain of the alleged deficiencies were identified as requiring supplementation of the EIA.
Those matters are (1) the impacts of construction of the Interim Solid Waste Staging Facility, (2) the cumulative dotes to the public from restart of TMI-l and decontamination of TMI-2, and (3) the environmental impacts of the alert-notification system for increased emergency preparedness.
These subjects are addressed below.
Construction Impacts of the Interim Solid Waste Staging Facility The Staff is still of the opinion that all construction relating to (Jnit I which would cause disturbance of land onsite and of adjacent waters is complete.
The interim solid waste staging facility is, to the Staff's knowledge, the only further outside construction connected in any way with Unit I which is planned prior to restart of that unit.
It will be built in a severely disturbed industrial area on the Island.
There will be no new environmental impacts.
The environmental impacts of the initial construc-tion disturbance were clearly spelled out in the Staff's 1972 FES (See NUREG-0112, page B-34).
gjo 5/302 76
\\
s The building will be directly south of the electrical switchyard and between it and the northern-most Unit 2 cooling tower.
It is designed to be a buffer against shipping delays or other problems and contains separate staging areas for low level wastes from each unit.
It will be, in the Staff's view, a significant improvement over the present staging facilities for low-level radioactive wastes from Unit 1 prior to snipment since a former construction storage building in the far southeast corner of the fenced-in area is now being used for this purpose.
G AN ASSESSMENT OF THE RISK TO HUMAN HEALTH TO INDIVIDUALS RESIDING AROUND TMI FROM THE COMBINED EFFECTS OF RADI0 ACTIVE RELEASES FROM DECONTAMINATION OF UNIT 2 AND NORMAL OPERATION OF UNIT 1 CONTENTS I.
INTRODUCTION II.
DOSES a.
Decontamination of Unit 2 b.
Operation of Unit 1 c.
Cumulative Dose III.
HEALTH EFFECTS a.
Decontamination of Unit 2 b.
Operation of Unit 1 c.
Cumulative Health Effects IV.
CONCLUSION V.
REFERENCES
e I.
INTRODUCTION This assessment evaluates the risk to human health for individuals in the general population (excluding TMI-workers) who may be exposed to radiation resulting from radioactivity that may be released during the normal decontamination of Unit 2 and from normal operation of Unit 1.
Section II presents radiation doses and Section III presents potential health effects. Dose estimates presented herein are taken from other documents as described.
Cumulative doses are presented in a manner for comparison to background doses. The cumulative risk estimates are compared to risks unrelated to releases from TMI and to commonly understood risks for activities that are generally considered normal.
1 j
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II. DOSES TO THE PUBLIC The dose estimates presented here are taken from other publications and are not the result of calculations made specifically for this assessment. Both maxinun individual dose estinates and population (50 mile radius) dose esti-mates are pre.eented.
II.h DECONTAMINATION OF UNIT 2 The potential offsite doses due to the cleanup of TMI-2 are estimated in the
" Final Programmatic EIS Related to Decontamination and Disposal of Radioactive Wastes Resulting From March 28, 1978, Accident at TMI Nuclear Station, Unit 2 (FPEIS).)) The methodology used in that report to perform dose estimates are 9/
those described in Regulatory Guide 1.109' with certain modifications.
The modifications and site specific parameters are given in Appendix W of the FPTIS.
In the suttrnary of the FPEIS it is stated that the total body dose to the maxi-mum exposed individual will range from 0.8 mrem to 2.3 mren, provided the cleanup is conducted in accordance with the staff's estimated effluent release, values.
In any event, proposed effluent release criteria will limit the dose to no more than 15 mrem /yr for airborne releases, and no more than 3 mrem /yr for liquid releases.
The FPEIS presents estinates of the popu'ation dose that would be expected to occur over the entire cleanup period from both gaseous and liquid releases. The population dose was estimated to range from 10 to 1000 person-rems (FPEIS, p.10-19),
depending upon the exact decontamination methods that are employed.
Table 1 lists the dose estinates for the maximum exposed individual for the entire decontanination program for atmospheric and liquid releases.
Entries
. +
are listed for each type of release, representing the full range of processing alternatives.
10 CFR 50, Appendix I design objective values are also listed.
Table 1.
Dose Estimates for the Maximum Expose 6 Individual for the Entire Decontamination Progran for Each Alternative, and Come'trison with 10 CFR 50 Requirements (from FPEIS, Table,10.11)
Dose (mrem)a (Total-body / max. oroan)
D Option Estimated Appendix I, value 10gFRy0 alpe Atmospheric Releases:
1.
Ship processed water offsite
- 0. 8/1. 8
-/15 2.
Natural Evaporation to Atmosphere 2.1/ 2. 0
-/15 3.
Forced Evaporation to Atmosphere -
SDS/EPICOR II Processing 2.3/3.4
-/15 4
Forced Evaporation to Atmosphere 505 Processing 120./480.
-/15 5.
Release Water to River - 505/
EPICOR II Processing 0.8/1.8
-/15 6.
Release Water to River SDS Processing 0.8/1.8
-/15 Liquid Releases:
1.
Ship processed water offsite
.0015/.0023 3/10 2.
Natural Evaporation to Atmosphere"
.0015/.0023 3/10 3.
Forced Evaporation to Atmosphere 505/EPICOR II Processing 0.8/1.1 3/10 4.
Forced Evaporation to Atmosphere 505 Processing 7.0/16.
3/10 5.
Release Water to River - SDS EPICOR II Processing 1.1/1.6 3/10 6.
Release Water to River SDS Processing 9.8/23.
3/10
'The dose estimates represent the contribution of all decontamination programs for the entire cleanup.
b00se estimates are listed separately for atmospheric releases and liquid releases, rather than adding them together, because different individuals are generally considered to be involved, and because the 10 CFR 50 dose objec-tives are different for each, cA small fraction of water vapor may precipitate as rain over the Chesapeake Bay watershed.
Table 2. lists dose estimates to the projected population in year 2010 residing within a 50 mile radius of TMI resulting from atmospheric and liquid releases from the facility. Two entries are listed and represent a bounding range of processing options.
Table 2.
Population Dose Estimates for the Population Residing Within 50 Miles of the Facility for the Range of Processing and Disposal Alternatives (From FPEIS, Table 10.12)
Decon tanination Estinated Dose Option (Person rem - Total Body)
Ship Processed Water Offsite 10 Forced Evaporation of SDS 3rocessed Water 1000 II.b OPERATION OF UNIT 1 To assure that the public will be adequately protected from radiation during normal operation of Unit I conditions for operation are imposed by technical specifications to the operating license. New technical specifications for Unit i have been submitted to NRC by Metropolitan Edison Company by letter dated October 30, 1979. They are under staff review for conformance with the require-ments of 10 CFR Part 20,10 CFR Part 50, including Appendix I and 40 CFR Part 190, and a license amendment will be required to incorporate these technical specific-ations.
For guidance, the staff has prepared example standard technical specific-ations for use by all licen:ues in preparing technical specifications.
For pressurized water reactors the standard technical specifications are described in NUREG-0472.-3/
The staff has reviewed aspects of the licensee's submittal which pertain to offsite radiation dose limits and offsite radiation monitoring. Their submittal follows NUREG-0472 in these areas.
. The mechanism by which the technical specifications assure that the public health and safety is protected is by imposition of offsite dose limits that, in turn, limit the amount of radioactive material that can be released. These limits are designed to assure that doses that could occur offsite are within certain plant design objectives which are described in the regulations i,3 CFR Part 50, Appendix I).
For example, for noble gases the technical specifications require that the noble gas air dose offsite be no more than 5 mrem to the total body, 15 mrem to the skin,10 mrad gamma radiation air dose and 20 mrad beta radiation air dose during any calendar year. The licensee is required to monitor the ' releases and to make cuarterly and annual dose calculations which are based on actual releases that occurred. If these calculations indicate that one of these requirements were exceeded, the licensee is required to report to NRC within 30 days.
Other limiting requirements fall into the following areas: 1) liquid effluent release rate, 2) liquid effluent dose, 3) gaseous effluent dose rate, 4) gaseous effluent dose (non-noble gases), and 5) total dose. The specification are as follows:
I
1.
The concentration of radioactive material in liquid effluents releases at any time from the site shall be limited to concentr aticns specified in 10 CFR Part 20, Appendix B, Table II, Column 2 for radionuclides other than dissolved or entrained noble gases.
2.
The dose or dose commitment to an individual from radioactive naterials in liquid effluents releases from the site shall be limited to:
i '
a)
During any calendar quarter not greater than 1.5 mren* to the total body and 5 mre.. to any organ.+
b)
During any calendar year not greater than 3 mren to the total body and not greater than 10 mrem to av organ.'
3.
The dose rate due to radicar'. 've materials in gaseous effluents from the site shall be limited to:
a)
For noble gases not greater than 500 mrem /yr to the total body and 3000 mrem /yr to the skin.
b)
For all radiciodines and for all radioactive materials in particular forn and radionuclides (other than noble gases) with half lives greater than 8 days, not greater than 1500 mrem /yr to any organ.
4 The rem is a measure of the dose of any ionizing radiation to the body tissues in terms of its estimated biological effect relative to a dose of one roentgen of X-rays.
The liquid effluent requirements are implemented at the point of discharge to the river, hence, the dose that could occur as a result of real water in'.akes downstream would be expected to be significantly snaller than those limited by this specification.
. 4 The dose to an individual from radioiodines, radioactive materials in particulate form, and radionuclides (other than noble gases) with hal f-lives greater than 8 days in gaseous effluents released from the unit shall be limited to:
a)
During any calendar quarter not greater than 7.5 mrem to any organ, b)
During any calendar year not greater than 15 mren to any organ.
5.
The dose or dose comitment to any real individual from uranium fuel cycle stur:es is limited to less than or equal to 25 nrem to the total body or any organ, and 75 mrem to the thyroid over 12 consecutive months.*
The actual maximum individual doses that may occur offsite due to TM1 -1 normal operation are expected to be less than the technical specification requirement listed above. Table 3 lists the staff's estimated doses to the maximum exposed individual as a result'of normal operation of Unit 1.
Table 3 - COMPARISON OF CALCULATED DOSES FROM OPERATION WITH SECTIONS II.A, II.8, AND II.C OF APPENDIX ! 'o 10 CFR PART 50 (Dose to Maximum Individual)
(From Ref. 4, Table 5-6)
Appendix I Dose Calculated Criterion Desicn Objectives Doses Liquid Effluents Dose to total body from all patowrys 3 arem/yr 2.0 mrem /yr I
Dose to any oroan from all pathweys 10 mrem /yr 2.7 mrem /yr Nrsble Gas Effluents Gamma dose in air 10 mrad /yr 3.4 mead /yr Beta dose in air 20 mead /yr 8.9 mrad /yr Dose to total body of an individual 5 trem/yr 2.0 mrem /yr Oose to skin of an individual 15 mrem /yr 5.5 mrem /yr a
Radiofodine and Particulates Dose to any organ from all patnways 15 mrer/yr 6.3 mrem /yr
' Carbon-14 and Tritium are included in this category.
- This specification is provided to meet the dose limitations of 40 CR 190, the so-called Environmental Protection Agency Fuel-Cycle Standard.
. Health risk estimates for the maximum exposed individual are presented below for both the value of 6 mrem / year, representing the "best estimate", and a value of 15 mrem /yr, representing the technical specification level. This value of 15 mrem /yr is considered to be a centervative (over estimate of true value) estimate of actual doses that are likely to occur.
Population doses for the paculation living within 50 miles of the plant were estimated to be in the range of 11 to about 20 person rems per unit (see Reference 5, p. 5-11 and " Final Environmental Statement for TMI, Units 1 and 2, 1972," p. V-19).-L/ A value of 15 person-rems /yr will be used for the health effects estimates presented below.
II.c CUMULATIVE DOSES Table 4 lists the dries and dose ranges for the cleanup operation at Unit 2 and for normal operation of Unit 1.
Also in the table the sum of the doses from both are presented.
The average yearly cumulative dose to the pooulation living within 50 miles of TMI for both the cleanup of Unit 2 and operation of Unit 1 is estimated to be in the range of 17 to 180* person-rems for the 6 year decontamination period. A longer decontamination pcried would result in a lower average yearly population dose.
i The value 17 was based on a 15 person-ren/yr dose #or coeretion of Unit 1 plus a 10 person rem dose fron Table 2 (low option) divided by 6 years; tr.e value 180 was based on the same dose f.om Unit 1 plus the hign option from Table 2, i.e.,1000 person-rem divided by 6 years.
Table 4 Dose Estimates for the Maximum Exposed Individual for Cleanup at Unit 2 and Normal Operation of Unit i Total Body Dose (mrem /yr)
Best Estimate of Technical Specification Dose Average Yearly Dose Over 6 Year During Any One Yeara Decontamination Program Decee of Unit 2 15.
9.2 - 15 Operation of Unit 1 15 6
Total 25Tt 6.2 - 21 a Values in this column are based on the assumption that both Cleanuo of Unit 2 and Operation of Unit 1 is at maximun allowable levels of 10 CFR Part 50, Appendix I.
The value 15 mrem /yr is the technical specification level resulting from radio-iodines and particulates ingested via atmospheric release pathways and applies as an organ dose level and not a total body dose level. Because radionuclides absorbed by the body via food ingestion generally concentrate in specific organs, it is likely that a given organ dose reaches the 15 mrem /yr level well before the total body dose reaches that level. Hence, the assumption of 15 mrem /yr total body, is considered to represent an upper bound of the technical specification l evel.
bThe value of 0.2 comes from Option 1 of Table 1 divided by 6 years; the value of 15. comes from option 4 which would be constrained by 10 CFR 50, Appendix I to a maximum annual dose of 15 mrem.
c40 CFR Part 190 limits the dose commitment to any real individual from uranium fuel cycle sources to 25 mrem /yr to the total body.
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_g.
Table 5 below indicates the dose for different parts of the country cue to natural background radiation to which all individuals are exposed every year.
The range of natural background values over the United States is 70 to 310 mrems 1
per year. The significance of a received radiation dose can be evaluated by comparison to natural background radiation. This has its ' basis in the fact that the human population has evolved in the presence of natural background radiation, and that there is no strong evidence that natural background radiation is linked to human mortality. Along these lines t.tr ':ational Council on Radiation protection 7/
and Measurements stated that (p.12)
"It is unwarranted to urge people to remove themselves from areas where exposure to natural sources of radiation are of this magnitude (400 mrem /yr). This degree of exposure is not regarded currently as of sufficient magnitude to require separate consideration in the determination and control of an individual's medical or occupational exposure.
There is no validated deleterious effect from natural background radiation in the portion of the population receiving the nigher ranges of natural radiation but it must be recognized that satisfactory epidemiological studies to determine such effects are probably impracticable."
Table 5 ESTIMATES OF NATURAL " BACKGROUND" RADIATION LEVELS IN THE UNITED STATES Annual Dose Rate (mrem / year) location Cosmic Terrestrial Internal Total Radiatica(a)
Radiation (a)
Radiation (b)
Atlanta, Georgia 44.7 57.2 28 130 Denver, Colorado 74.9 89.7 28 193 Harrisburg, Pennsylvania 42.0 45.6 28 116 Las Vegas, Nevada 49.6 19.9 28 98 New York, New York 41.0 45.6 28 115 CC) 28 107 Pennsylvania 42.6 36.2 Washington, DC 41.3 35.4 28 105 United States (d)40-160 0-120 28 70-310 (a)from [( 8 ) Table A-1]
(b)Sased upon total for soft tissue (gonads) doses from [( 9 ) Tables 42 and 43,
~
- p. 104].
(c)From [(.8 ) Table A-2]
(d)From [( 3 ), Table 15, p. 34]
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' The comparison of the maximum individual doses that may occur as a result of cleanup of Unit 2 and operation of Unit 1 to levels of natural background radiation and to spatial variation in natural background radiation suggests that the increased radiation dose from the plant is insignificant.
In a similar fashion the natural background dose can be compared to the population dose due to the plant. Approximately 2.2 million people reside within the fifty mile radius of the plant. On the basis of Table 4, the annual natural background population dose would be about 255,000 person-rem, compared to the range of 17 to 180 person-rems from TMI.
These comparisons suggest that the combined effect of cleanup of Unit 2 and operation of Unit 1 on the population will be insignificant from the offsite environmental radiation dose standpoint.
III. HEALTH EFFECTS P.adiological doses to the general public from radioactive releases from TMI may result in:
a.
Late somatic effects in the form of fatal and non-fatal cancer in various body organs, following age-and organ-specific laten y (delay) periods within the exposed population, and b.
Fatal and non-fatal genetic disorders in future generations of the exposed population.
Estimates of these health effects, which could occur randomly in an exposed population, are normally based on estimates of cumulative population dose expressed as person-rems (average dose X number of people receiving dose).
population health effect estinates presented here reflect the total effect incurred by the population.
In order to quantify individual risks, calculations are also presented here for the naximum exposed individual. Absolute risk
. 6 estimators of 135 deaths from latent cancer per 10 total-body person-rems in 6
the exposed population and 258 cases of genetic disorders per 10 total-body person-rems in the future generations of the exposed population were derived by the National Academy of Sciences Committee on the Biological Effects of Ionizing Radiation in the 1972 BEIR report--10/
and the Reactor Safety Study (WASH-1400, October 1975).--11/The derivation assumes a linear, nonthreshold dose-effect relationship at all sublethal dose levels.* Using the above risk estimators for cancer deaths and diseases related to genetic disorders, health risks as a result of releases from TMI were calculated for the population residing around TMI and for the maximum exposed individual. The results of these calculations are described below.
III.a DECONTAMINATION OF UNIT 2 The potential health effects to the 50 mile population due to the cleanup of THI-2 are estinated in the FDEIS. Table 6 (taken from FPEIS, Table 10.12) lists the potential number of cancer deaths or genetic abnormalities, designated as rates, for the 50 mile population of 2.2 million people around TMI as a result I
of decontanination activities. As these values are much less than 1 they suggest that it is very unlikely that any future cancer death will occur in the exposed pop-ulation over the remaining lifetime of the poDulation, or that any genetic ab-nornality will occur in the next 5 generations of the exposed population that could be associated wi th the cleanup operation. A better appreciation of the neaning
- The latest report by the National Academy of Scignces Committee on the Bio-logical Effects of Ionizing Radiation, BEIR-III, 2 / suggests that the cancer risks may be even smaller than those of the 1972 BEIR report by a factor of obout 2 or 3.
~
. 7 of the numeric values ir. Table 6 can be gleaned by comparison of the rates of Table 6 to expected cancer death rates and genetic abnormality rates from causes other than TMI releases in the same population.
For examole, in 1976, about
-13 20 percent of all deaths in the United States were due to cancer. j If those statistics are applied to the 2.2 million people living within 50 miles of TFI, the number of people in this population expected to die of cancer is 440,000.
This number can be directly compared to the numeric rates in Table 6 This comparison indicates that tha incremental chance of fatal cance" to the pop-ulation or to an average individual in the population due to the decontamina-tion activities is in the range of I chance in 400 million to 1 chance in 4 million, depending on the decontamination option that is chosen.
Table 6.
Estinates of Potential Cancer Death Rate and Potential Genetic Abnormality Rate for Exposure of the Population Around TMI Due to Releases From Decontamination for the Range of Processing and Dfspo~ sal Alternatives
~
a i
b Rate (deaths or abnormalities per 2.2 million oeople)
Estimated Cancer Fatal-Genetic Dose ity over Abnormality Decontanination (person-ren Remaining over Next 5 Ootion total bodyl Li fetime Generations Ship processed water o f fsi te 10 1 x 10-3 3 x 10-3
~ Forced evaporation of - SDS processed water 1000 1 x 10-I 3 x 10-I a
All estimates munded off to one significant figure.
l bPopulation death or abnormality rate estimates are expected to be slightly l
l smaller than the values presented here because the year-2010 population estimate of 3.2 million people was used for dose estimates from atmospheric pathways.
t l
. The BEIR-I report describes the normal incidence of diseases in which there is some evidence as being associated with a genetic component abnornality as 6 in 100, or 6 percent (p. 57, Table a, of Ref.10). In a similar fashion as was done for cancer death rates, the genetic abnormality rate due to the decontamination and decommissioning activities at TMI can be compared to the incidence of diseases related to genetic abnormalities from causes other than TPI releases.
For the 2.2 million people in the 50 mile radius around THI the expected incidence of non-TMI related genetic abnormalities is 132,000 (0.06 x 2.2 x 106 = 132,000).
Comparing this to the rates of Table 6 indicates that the incremental chance of a genetic abnormalities to descendants of this population or to an average exposed individual in it over the next five generations ranges from 1 chance in 40 million to 1 chance in 400 thousand, depending upon the decontamination options which are used.
. Table 7 lists the increased risk of potential cancer and genetic abnormalities due to radiation released from the cleanup of Unit 2 for the maximun exposed individual.
Stated in other words, an individual dose of 0.8 to 2.3 nrem would incur an l-estimated increased risk of dying from cancer of between 1 in 2 million and 1 in 600,000, and an increased risk of a genetic effect to descendants over the next five generationc of between 1 in 300,000 and 1 in 100,000.
Similarly, an individual dose of 15 mrem would incur an estimated increased risk of dying from cancer of 1 in 100,000 and an increased risk of a genetic effect to des-cendants over the aext five generations of 1 in 10,000.
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Table 7.
Increases in Maximum Exposed Individual Risk Estimates Over Background Due to the TMI-2 Cleanup Increased Risk to Maximum Exposed Individual Over Background Maximum Exposed Individual Li fetimea Genetico Dose Cancer Estimated 0.8 - 2.3 5.4 x 10 5 - 1.5 x 10-4 3.4 x 10 9.9 10~
Dose (mrem)
Maximum Dose (mrem) 15 1.0 x 10-3 6.5 x 10~3 a Value determined by multiplying cancer risk estimator (135 x 10-6/ person-rem) by the dose, divided by the normal background incidence rate (.20).
b Value determined by multiplying genetic risk estimator (258 x 10-6/ person-rem) by the dose, divided by the normal background incidence rate (.06).
III.b OPERATION OF UNIT 1 The population dose to the population residing within 50 miles of TMI is presen:cd above as about 15 person-rems per year. As was done in the previous section, the po-tential cancer and genetic health effccts are estimated. Table 8 lists these estimates.
The numeric values in Table 8 can be put in relation to background incidence rates for t
potential cancer and for genetic abnormalities. This results in an increrrental chance of fatal cancer to the population or to an average individual in the population of 1 part in 200 million, and in an incremental chance of diseases related to i
genetic abnormalities to the population or to an average individual in the pop-ulation of 1 part in 33 million.
16 -
Ta ble S.
Estimates of Cancer Death Rate and Genetic Abnormality Rate for Exposure of the Population Around TMI Due to Releases During Operation of Unit 1 Ratea (deaths or abnormalities per 2.2 million people)
Estimated Cancer Fatal-Genetic Population Dose ity over Abnormality (person-rem Remaining over Next 5 total body)
Li fetime Generations 15 2 x 10-3 4 x 10-3 a All estimates rounded off to one significant figure.
The expected maximum individual dose due to operation of Unit 1 is presented above as 6 mrem /yr with an upper limit of 15 mrem /yr.
The preceding section-describes the increased risk over background incidence rates for a dose of 15 mren as 1 part in 100,000 for cancer death and 1 part in 10,000 for genetic related effects.
i III.c CUMULATIVE HEALTH EFFECTS Table 9 lists the potential health effects and health effect ranges for the cleanup operation of Unit 2 and normal operation of Unit 1 for the maximum exposed individual. Also the sum of potential health effects for both are presented in the table.
The cumulative risks to the maximum exposed individual are of order 10-6, The average yearly cumulative dose to the population living within 50 miles of TMI for both cleanup of Unit 2 and operation of Unit 1 is presented above as within the range of 17 to 180 person-rem /yr during the decontamination period.
The potential health effects rates for the population of 2.2 million peopic is
17 -
2.3 x 10-3 to 2.4 x 10-2 for cancer and 4.4 x 10-3 to 4.6 x 10-2 for genetic related diseases. The potential health effect rates for the average exposed individual is 2.2 x 106 times smaller than these rates, or of order 10-9 to 10-8, Ta bl e 9.
Estimates of Potential Health Effects For The Maximum Exposed Individual for Cleanup of Unit 2 and Normal Operation of Unit 1.
a Rate (death or abnormality for the maximum exposed individual per year) ffaximum Possible Average Expected Rate Rate Cancer Genetic Cancer Genetic Death Abnormality Death Abnormality Cleanup of Unit 2 2.0 x 10-6 3.9 x 10-6 2.6 x 10 5.1 x 10-8 2.0 x 10-0
- 3. 9 x 10~-
Operation of Unit 1 2.0 x 10' 3.9 x 10' 8.0 x 10-7 1.6 x 10-6 Total 4.0 x 10-6 ~
7.8 x 10-6 8.3 x 10-7 _
1,7 x 7 3 -6,!
2.8 x 10-6 5.5 x 10-6 a Values based on doses of Table 4 multiplied by the risk estinators described above.
As was done above, the meaning of a risk can be better understood by comparison to natural incidence rates. As absolute risk of order 10-6 of cancer death is equivalent to an increase in the enance of dying of cancer of 1 part in 200,000.
An absolute risk of order 10-6 of genetics abnormality is equivalent to an I
increase in the chance of offspring with genetic abnormalities of 1 part in 60,000.
Another way of evaluating the meaning of a risk of order 10-6 or 1G-8 is by study of risks from other activities that are considered normal. Table 10 lists activities that result in a risk of order 10-6 These comparisons suggest that the risk level of 10-6 for the maximum exposed individual and 10'8 for the average exposed individual are negligible.
1
Table 10. Activities with Lifetime Risks of Order 10-6 (Reference 14, p.188)
Type of Activity Equivalent Mortality Risk of 10-6 Automobile travelling 50 miles Commercial flying 250 miles Seing a man age 60 20 minutes The activities in Table 10 are ones in which individuals have some control over.
Accidents that also have a risk order of 10-6 per year in which an individual has no control over are deaths incurred by lightning, tornadoes, or hurricanes (see reference 11, p. 3, Executive Summary).
IV. CONCLUSION The cunulative population doses for the populaticn residing within 50 miles of TMI, and maximun individual doses are presented.
Effects of decontamination of Unit 2 and normal operation of Unit 1 are considered. The doses for either the maximum exposed individual or for the average exposed individual are a small fraction of natural background and within the range of geographical variation of natural background.
Potential health effects are presented for the population and for the maximum individual based on the estimated doses. The magnitude of risk is compared to non-TMI related incidence rates of cancer and genetic abnormalities and to risks of activities which are considered normal.
i
9 19 -
On the bas's of the comparison of doses to natural background, and natural background fluctuations, and on th'e basis of the con.:arison of risks from radiation releases from TMI to normal background risks and to risks of activities considered normal, it is concluded that the combined effects of the cleanup of Unit 2 with normal operation of Unit 1 will result in insignificant risk to the public health.
4 t
--,3 w
~m-.
V.
REFERENCES 2
1.
Final Progranmatic Environmental Impact Statement Related to Decon-tamination and Disposal of Radioactive Wastes Resulting from March 28, 1979, accident at TMI-2," NRC Report NUREG-0683, Vol.1 & 2, U.S.
Nuclear Regulatory Commission, March 1981.
2.
USNRC Regulatory Guide, " Calculation of Annual Doses to Man from Routine Releases of Reactor Effluents for the Purpose of Evaluating Compliance with 10 CFR Part 50, Appendix I," NRC Report 1.109, October 1977, Rev.1.
3.
U.S. Nuclear Regulatory Commission, " Radiological Effluent Technical Specifications for PWR's," July 1979, NRC Report NUREG-0472, Rev. 2.
4.
"TMI-l Restart", NRC Report N'JREG-0630, Office of Nuclear Reactor Regulation, U.S. NRC, June,1980.
5.
USNRC, " Final Supplement to the Final Environmental Statement Related to Operation of TMI-2," December 1976, NRC Report NUREG-CI'2, Wasning-ton, D.C.
6.
Ibid., Appendix 3.
7.
National Council on Radiation Protection and Measurement, " Basic Radiation Protection Criteria," NCRP Report No. 39, NCRP, Washington, D.C., Jan.15, 1971.
8.
D.T. Oakley, " Natural Radiation Exposure in the United State," EPA Report ORP/SID 72-1, U.S. Environmental Protection Agency, Washington, D.C. (1972).
9.
National Council on Radiation Protection and Measurements, " Natural Back-ground Radiation in the United States" NCRP Report No. 45, NCRP, Washing-ton, D.C., November 15, 1975.
- 10. Advisory Committee on the Biological Effects of Ionizing Radiation (BEIR)
"The -Effects on Populations of Exposure to Low Levels of Ionizing Radia-ticn," National Academy of Sciences - National Research Council, Washington, D.C., November 1972.
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Pochin, E., "The Acceptance of Risk," British Medical Bulletin, 31, 3, 184-190 (1975).
The Environmental Impacts of the Emercency Operations Facility Specific design and siting infonnation on the Three Mile Island Emergency Operations Facility (EOF) is not available at this time.
Criteria for the EOF are provided in NUREG-0696.
Functional Criteria for Emergency Resnonse Facilities.
The staff believes that the environmental impacts of an EOF are minor, comparable to those of a small office building with working and conference space for at least 35 persons.
The Environmental Imoacts of the Alert-Notification System The proposed emergency preparedness alert-notitication system for Three Mile Island Nuclear Generating Station is based on 83 sirens located to assure direct coverage of essentially 100 percent of the population within about 1.0 miles of the site.
The sirens will be mounted on wooden utility posts and strategically located near schools and firehouses wherever possible.
Criteria to be met or exceeded by this system are provided in NUREG-0654, Criteria for Preparation and Evaluation of Radiological Emergency Response Plans and Preparedness in Support of Nuclear Power Plants, Revision I, Appendix 3.
Tne system will meet the acceptable dissonant sound level described in the Feceral Emergency Management Agency publication CPG-1-17, " October Warning Systems Guice".
The sound levels received by any member of the public will be lower than 123 dbC, the level which may cause discomfort to individuals.
Siren testing guidance requires a silent test every two weeks, a growl test quarterly and when preventive maintenance is performed, and a complete cycle test at least annually and as required for formal exercises. Advanced warning of complete cycle tests through newspapers, radio enc. television will minimize public disruption and confusion.
After reviewing the design and testing criteria to be applied to the proposed TMI system, the staff concludes that the environmental impacts of placement and testing of the proposed system will be minor.
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