ML19261D332
| ML19261D332 | |
| Person / Time | |
|---|---|
| Issue date: | 05/18/1979 |
| From: | Hendrie J NRC COMMISSION (OCM) |
| To: | Waxman H HOUSE OF REP., INTERSTATE & FOREIGN COMMERCE |
| Shared Package | |
| ML19261D333 | List: |
| References | |
| NUDOCS 7906110300 | |
| Download: ML19261D332 (3) | |
Text
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[#'",%[g UNITED STATES NUCLEAR REGULATORY COMMISSION j f gl; WASHINGTON, D. C. 20555 k.,,[
May 18, 1979 CHAIRMAN The Honorable Henry J. Waxman, Chaiman Subcomittee on Health and the Environment Committee on Interstate and Foreign Comerce U. S. House of Representatives Washington, D. C.
20515
Dear Mr. Chairman:
Thank you for your letter of April 13, 1979, regarding radiation exposure of workers in nuclear power plants.
This is also a topic of great interest to the NRC.
Please be assured that we will gladly provide any assistance you might need in order to evaluate whether workers and the general public are protected from unwarranted exposure to radiation from nuclear facilities.
In response to your specific request, I have enclosed a copy of an NRC annual report on occupational radiation exposure for 1977. Tables 5 and 6 of this report (pages 14 and 15) provide data on man-rems per megawatt year for 57 comercial power light water reactors (LWR) which operated during that year.
It appears that the data submitted to you by Mr.
Ralph Nader and Dr. Sidney Wolfe are accurate and were taken from this NRC report.
In assessing the significance of data on man-rem exposure per megawatt-year, one should note that LWR's with higher man-rem per megawatt-year values are mostly older plants with smaller generating capacities.
A large man-rem to megawatt-year ratio in combination with a high yearly man-rem total generally indicates that a plant was shut down for refueling and/or extensive maintenance or modifications.
In 1977, boiling type LWR's perfomed a great deal of feedwater nozzle /sparger work which accounted for a large percentage of the exposures at these plants. Other major activities included work on core spray lines, the reactor water cleanup system, main steam isolation valves, and main condenser. At pressurized type LWR's large exposures were incurred during inspections and repair of degraded steam generator tubes. Thus, it appears that the man-rem per megawatt-year ratio is quite dependent upon the amount of unusual maintenence required at a particular plant.
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Honorable Henry J. Waxman In addition to limiting exporure of individual workers, it is also important to limit the collective (man-rem) dose to all workers involved.
This follows directly from the recognition that some degree of risk should be u sociated with any level of radiation exposure. The NRC, its pred.!cessor the AEC regulatory staff, the Environmental Protection Agency, and numerous radiation protection organizations have long followed the practice of assessing risk of low-level exposure according to the linear hypothesis. According to this hypothesis, some degree of risk is associated with any radiation exposure and that risk is directly and linearly proportional to the dose.
Several members of the scientific community have recently published information which suggests that the linear hypothesis is no longer a suitable basis for estimating the biological effects of radiation delivered at low doses and dose rates.
Certain of these scientists maintain that the linear hypothesis overestimates the risk; others are convinced that the risk is underestimated by the linear hypothesis.
Scientific Committee 40 of the National Council on Radiation Protection and Measurements (NCRP), in a report as yet not published (draft, February, 1979) or accepted by the full NCRP, presents a comprehensive review of existing radiobiological data and concludes that the linear hypothesis overestimates the risk from exposure to X, gama, and beta radiation by a factor of 2 to 10 at low doses and dose rates.
The United Nations Scientific Comittee on the Effects of Atomic Radiation (UNSCEAR), in
" Sources and Effects of Ionizing Radiation," 1977, has published similar conclusions.
On the other hand, recently completed interpretations of epidemiological data (one by Drs. Mancuso, Stewart and Kneale and two others by Dr. Irwin Bross and Mr. N. Natarajan) indicate that the linear hypothesis underestimates the risk by a factor of 10 or considerably more.
The regulatory strategy adopted by NRC to assure adequate protection of workers stresses limitation of both individual exposures and collective exposures. There are several effective approaches to limitation of collective exposure.
One such flows directly from the implementation of requirements that radiation exposures of individuals be maintained as low as reasonably achievable.
(This concept is often characterized by the acronym ALARA.)
In nuclear power plants the ALARA requirement translates into a broad program of actions and controls all directed toward reducing worker exposure. A good ALARA program includes such things as plant design and layout to facilitate maintenance; requirements on fuel cladding, water treatment and purification systems to inhibit corrosion or reduce deposition; controls on access to radiation areas; worker training; radiation surveys; use of remote and semi-remote maintenance equipment; local decontamination of surfaces; special ventilation systems; protective clothing, etc. -- in short, a complex wide-ranging exposure control program.
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Honorable Henry J. Waxman Another effective way of controlling collective dose would be the development and establishment of collective dose limits for specific facilities in addition to dose limits for individual workers.
One of many alternative methods whereby the NRC could establish the collective dose limits would be to set an absolute dose limit that is dependent upon the megawatt-years of electricity produced, as proposed by Drs. Morgan and Wolfe and Mr. Nader.
The NRC, the Environmental Protection Agency and the Department of Labor (OSHA) plan to hold public hearings this summer regarding the adequacy of current occupational exposure standards for workers.
One item which will be discussed at that hearing is whether it is advisable to establish collective dose limits as well as dose limits for individual workers.
Other information regarding this issue has been prepared by the NRC staff in response to petitions by the Natural Resources Defense Council and other members of the public regarding lowering of individual occupa-tional exposure limits.
I have included these documents for your informa-tion since they more 'ully describe the NRC staff views regarding the regulation of worker exposure to radiation.
Additionally, in February of this year, we published a Federal Register notice soliciting public coment on a proposed amendment to our regulations which would eliminate the accumulated dose averaging formula and impose annual dose-limiting standards while retaining quarterly standards. A copy of that Federal Register notice is enclosed.
Since 10 CFR 20.407 does not require that power reactor operators submit exposure data for calendar year 1978 until March 31, 1979, the NRC has not yet been able to update this information for 1978 or 1979. We will, however, fomard to you a copy of " Occupational Radiation Exposures at Light Water Reactors - 1978" when the report is published.
Please do not hesitate to contact me if you wish further information on any of these important topics.
Sincerely, eph M. Hendrie
Enclosures:
1.
NUREG-0463 2.
SECY 78-415 3.
Federal Register Notice -
Proposed Rule to Amend 10 CFR Parts 19 & 20 2159 090 i
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committee en interstate enn sorrip commme Glasf%ngton, D.C. 20515 April 13, 1979 Honorable Joseph Hendrie Chairman U.
S. Nuclear Regulatory Commission Washington, D.
C.
20555
Dear Chairman Hendr.:
.e:
The Subcommittee on Health and the Environment has received disquieting information concerning radiation at a number of nuclear power plants.
According to Ralph Nader and Dr. Sidney Wolfe, thirty-two of the forty-two nuclear power plant sites had ratios greater than 0.5 man-rems per megawatt year in 1977.
The Subcommittee would appreciate your examining the enclosed list verifying that the reported radiation levels for 1977 exist, and indicating whether you have updated levels for 1978 and 1979.
At the present time, there are no standards for overall plant radiation levels.
One must be concerned that a careless attitude about workers' health may be indicative of less than optinal concern for many of the health protection issues of the public at large.
We will anticipate receiving your determination on the accuracy of these radiation levels no later than Monday, April 30, 1979, and whether or not the Nuclear Regulatory Commission expects to promulgate a standard.
If you have any questions, please contact Elliot Segal, Staff Director of the Subcommittee at 225-4952.
Thank you for your cooperation and assistance.
Sincerely,
/k m HENRY A. WAXMAN Chairman HAW:esa Enclosure GQj 2.cm)3i
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i April 13, 1979 Henry A. Waxman Chairman Subcommittee on Health and the Environment House Committee on Interstate and Foreign Commerce 2125 Rayburn Office Building Washington, D.C.
20515
Dear Congressman Waxman:
In the current issue of the New Scientist, Dr. Karl Z. Morgan, Professor of Health Physics at Georgia Institute of Technology and generally a supporter of nuclear energy, recommends that the government "take immediat reduce the [ worker] man-rem [ radiation] dose"g measures to at nuclear power plants.
To accomplish this, Dr. Morgan suggests a plant-by-plant limit on annual worker radiation exposure per unit of electricity generated of 500 man-rems per 1000 megawatt ('elec trical) year or 0.5 man-rem /MW-yr. for pre-sently operating plants and those under construction and a ratio of 0.2 for plants now on the design board.
As shown in the accompanying chart, of the 42 sites in the U.S. with one or more commercial nuclear power plants,
32 had ratios of greater than 0 5 man-rems per megawatt year in 1977 The worst plant--Lacrosse at Sparta, Wisconsin--had 20.45 man-rees per megawatt year or 40.7 times more worker exposure per megawatt year than the 0 5 upper limit recc.Tmend-ed by Dr. Morgan.
The next worst, Pilgrim at Plymouth, Fas s.
had 9.91 man-rems per megawatt year or 19.8 times more than the maximum recommended by Dr. Morgan.
For the whole country, in 1977, there were 32,511 man-rems of worker radiation exposure for 25,584 megawatt years of electricity generated.
This is a ratio of 1 3 or 2.6 times higher than the 0 5 man-rem per megawatt year limit recommended by Dr. Morgan.
1.
New Scientist, 5 April 1979,18-21.
2.
This is the sum of all worker radiation exposures at a given plant for a year.
=>
Henry A. Waxman April 13,1979 As can be seen, some plants are doing much better than others.
The plant with the worst ratio, Lacrosse, had 120 times more radiation per megawatt year (225 man-rems per 11 megawatt years or 20.45) than the plant with the lowest ratio, Palisades in Kaiamazoo, Michigan (100 man-rems per 580 mega-watt years or.17).
While Dr. Morgan believes that the allowable exposure per worker per year C5 rems, 12 rems for some) is also too high, he recommends lowering it to 2 5 rems per year.
(We and others have recommended lowering to 0 5 rem per year. )
He is concerned, however, that there also needs to be a cap on total exposure per plant to prevent utilities from simply spreading an increasing radiation dose among larger number of workers.
Much of this werker exposure is due to breakdown in the cooling system and the failure of present design to protect workers.. As long as this lack of " containment" has "only" affected workers, industry and the NRO have considered it tolerable to society.
The events of Three Mlle Island have shown us again that no problem, be it asbestos, vinyl chlor-ide or radiation, affects only workers.
If inadequate atten-tion is paid to worker health, eventually the surrounding community will also suffer as the risk diffuses out of the workplace.
As Chairman of the House Health Subcommittee with a long-time concern about worker radiation health hazards, we hope you will urge the Nuclear Regulatory Commission to impose an upper limit no higher than 500 man-rems per 1000 megawatt years for all U.S. atomic power plants with penalties for failure to meet this limit within a specified period of time and re-vocation of operating licenses for all plants with extended violation of this linit.
We are currently drafting a petition to NRC for a regulation to impose such limits.
Sincerely, A
Ralph Nader
(,
On C).
Sidney A. Wol e, M.D.
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RANKING OF U.S. ATOMIC POWER PLANTS BY WORKER RADIATION EXPOSURE PER U."IT OF ELECTRICITY GENERATED IN 1977 0
a Man Rems /
Times higher MW-Yr.1 than recommende
.2 nk State City Atomic Plant in lo77 by Dr. Mor ca n' 1.
Wisconsin Sparta Lacrosse 20.45 40.72 2.
Massachusetts Plymouth Pilgrim 9.91 19.82 3
Michigan Grand Rapids Big Rock Point 7.59 15.18 2
New Jersey Lakewood Oyster Creek h.18 8 36 5
New York Oswego Nine Mile Point 3.99 7 98 6.
1.~ o. Carolina Wilmington Brunswick 2 3.86 7.72 7.
California San Diego San Onofre
?.18 6.36 5.
Massachusetts Northampton Yankee Rowe 3.04 6.08 9
Minneso ta Minneapolis Monticello 2 34 4.68
.3.
Ne. York Oswego Fitzpatrick 2 34 4.68
.1.
Virginia Newport News Surry 1&2 2.13 4.26 2.
Pe nnsylva nia York Peach Botton 1&2 1 94 3.88 3
Illinois Chicago Dresden 1,2&3 1.50 3 00
.4 Connacticut Fdddletown Haddam Neck 1.40 2.80 5.
'!ew York Rochester R.E. Ginna 1.16 2.32
.6.
Florida Miami Turkey Point 3&4 1.12 2.24
.7.
Illinois Rock Island Quad Cities 1&2 1.06 2.12
_S.
Georgia Savannah EI Hatch 1.04 2.08 9
Maryland Annapolis Calvert Cliffs 1 98 1.96
!O.
So. Carolina Florence H.B. Robinson 2 92 1.84
- 1.
So. Carolina Greenville Oconee 1,2&3
.89 1.78
.qfi 59 094178
'2.
Nebraska Omaha Fort Calhoun
'3 New York White Plains Indian Point 2&3
.87 1.7L
D**
- D'3 P
b ev I um Man Rems /
Times highe:
o eu MW-Yr.7 than recommen
.ank. State City Atomic Plant in 1977 by Dr. Morca
'4.
Iowa Cedar Rapids Duane Arnold
.84 1.68
'5.
Illinois Chicago Zion 1&2 78 1.56 6.
Connecticut New London Mills tone Point 1
.58 1 36
?7.
Alabama Athens Brown's Ferry 1&2
.65 1 30 28.
Vermont Brattleboro Vermont Yankee
.61 1.22 19 California Sacramento Rancho Seco 58 1.16
'O.
Pennsylvania Harrisburg Three Mile Island 1 58 1.16
'l.
Michigan Kalamazoo DC Cook 1 55 1.10 22.
Wisconsin Vanitowac Point Beach 1&2 52 1.04 RECOMMENDED LIMIT OF 0,5 MAN-REM PER MEGAWATT-YUAR OF ELECTRICITY GENERATED 23.
Connecticut New London Millstone Point 2
.49 98
'4 Arkansas Little Rock Arkansas 1
.42
.84 i5.
F.aine Augusta Maine Yankee
.42
.84 6.
Nebraska Lincoln Cooper Station 37 74 27.
Wisconsin Green Bay Kewaunee 35
.70 38.
Minne sota Minneapolin Prairie Island 35 70 l9 Dennsrivania Pittsburgh 5eaver Valley
.27 54 0.
Florida Fort Pierce St. Lucie
.25 50
- 1.
Oregon Portland Trojan
.23 46 2.
Miclai;an Kalamazoo Palisades
.17 34 1.
Total mar-rems of worker exposure divided by megawatt-years of elec tricity generated at each plant, or a " risk / benefit" ratio.
2.
Dr. Karl Z. Morgan, Neely Professor in the School of Nuclear Engineering at Georgia Institute of Technology, recommended in an article in New Scientist April 5,1979, that existing atomic plants be limited to 0 5 man-rem or radiaticn exposure per megawatt-year of electricity generated.
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