ML20053A697
| ML20053A697 | |
| Person / Time | |
|---|---|
| Issue date: | 04/27/1982 |
| From: | Palladino N NRC COMMISSION (OCM) |
| To: | Ottinger R HOUSE OF REP., ENERGY & COMMERCE |
| Shared Package | |
| ML20053A698 | List: |
| References | |
| NUDOCS 8205270146 | |
| Download: ML20053A697 (15) | |
Text
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i April 27, 1982 OFFICE OF THE CHAIRMAN r
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The Honorable Richard Ottinger, Chairman t'iNY 11 l002# ~-
Subcommittee on Energy Conservation and Power
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Committee on Energy and Commerce M
United States House of Representatives 9
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Dear Mr. Chairman:
Your letter of April 9,1982 forwarded a number of questions concerning occupational exposure associated with the operation, maintenance and modification of commercial nuclear power plants.
I am enclosing for the Subcommittee the Commission's answers to those questions.
If you require additional information, please do not hesitate to call upon us.
Sincerely, 7(.q
&W Nunzio d. Pal dino Chairman
Enclosure:
As stated cc:
Rep. Carlos Moorhead t
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QUESTION 1.
Does the NRC maintain, or require its licensees to maintain, complete exposure records for all workers in radioactive portions of a nuclear facility?
ANSWER.
NRC licensees are required to maintain records of the radiation exposures of all individuals for whom personnel monitoring is required (10 CFR 20.401).in The individuals for whom personnel monitoring)is required are specified 10 CFR 20.202.
In general, this includes, (1 each individual who is.ikely to receive a dose in any calendar quarter in excess of 25 percent of an NRC quarterly dose limit (25 percent of: 1 1/4 rem whole body, 18 3/4 rem to the extremities or 71/2 rem to the skin of the whole body), (2) each individual under 18 years of age who is likely to receive a dose in excess of 5 percent of a quarterly dose limit, or (3) each individual who enters a high radiation area.
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s QUESTION 2.
Does NRC maintain a " tracking" system for licensees to ensure against overexposure of individual workers who may work at more than one nuclear facility?
l ANSWER.
No.
When an individual terminates his or her employment or assignment with a nuclear power plant (as well as certain other types of licensees) the licensee must furnish to the NRC a report of the individual's exposure to radiation and radioactive material incurred during the period of the employment or assigr. ment (10 CFR 20.408).
These termination reports are computerized and can be used, after the fact, to determine whether the individual has received an overexposure as a result of multiple employments.
Such overexposures are very rare.
The responsibility for preventing overexposures as a result of multiple employments is placed on the licensee as explained in response to Question 3.
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4 QUESTION 3:
Does the NRC maintain, or require its licensees to maintain, a screening process to determine whether an applicant has worked or been exposed at any other nuclear facility or has exceeded his or her exposure limits at the same nuclear facility?
ANSWER.
NRC regulations state (10 CFR 20.102) that each licensee must require iny individual who may receive more than 25 percent of an NRC quarterly do.e limit (10 CFR 20.101(a) and 20.104(a)) to disclose in a written, signed statement either that the individual had no prior occupational dose during the current calendar quarter, or the nature and amount of any occupational dose which the individual received during that quarter from work at other licensed facilities. Any dose received during the quarter at other facilities must be subtracted from the allowable dose on the new job.
In this manner, the regulations establish that the quarterly dose limits are applicable to
' the total. dose received in that quarter by the worker, regardless of how many different facilities may have been involved. To make this system work, licensees are required to provide terminating workers with dose estimates promptly upon request (10 CFR 19.13).
This' system is also applicable when an individual works at a given facility, terminates, and then returns for additional work during the same quarter.
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-r QUESTION 4.
Does the NRC maintain, or require its licensees to maintain, long-term health records of employees who have been radiologically exposed to determine long-term health effects of ionizing radiation?
ANSWER.
The NRC does not maintain or require its licensees to maintain long-term health records of nuclear workers for the purpose of determining health effects of ionizing radiation.
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QUESTION 5.
What activities does the NRC conduct in conjunction with the Transuranic Register?
If none currently, have there been such activities in the past?
Is the NRC considering instituting or reinstituting its participation in the Register?
If not, why not?
ANSWER.
The NRC has participated in the Transuranic Register since.the establishment of the Register in the late 1960's.
The NRC routinely provides the Register with identification and exposure information for those individuals that,are reported to the NRC as being exposed to excessive concentrations. of radionuclides in the transuranic series.
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QUESTION 6:
Please describe in sufficient detail each program referred to and numerically identified in the following excerpt from the ACRS report previously cited.
We are encouraged to note that the NRC has recognized the importance of this problem and has completed (1) initial steps for developing a comprehensive research program for addressing the associated regulatory needs.
We are en-couraged also to see the (2) related research activities that have been developed to fill voids in the regulatory aspects of a wide variety of problems associated with the protection of workers at nuclear facilities.
ANSWER.
The basic objective of the occupational radiation protection program m
within the Office of Nuclear Regulatory Research is the development of a comprehensive body of regulations, guidance and information which assure an adequate degree of radiation protection for workers in NRC-licensed activities. The program consists of seven elements:
(1) occupational ALARA (as-low-as-reasonably-achievable),. (2) health physics measurements improvement, (3) internal dose control, (4) personnel performance improvement, (5) dose rate / working time reduction, (6) licensing improvement, and (7) a continuing program of examining our basic Standards for Protection Against Radiation (10 CFR 20) for necessary revisions to reflect new concepts in protection and new technical information.
Integrated with this program of health physics research and standards development is a health effects program that examines questions of improvements in calculating estimates of health risk from exposure and sponsors some biological research oriented to NRC's regulatory needs.
For most information on the biological effects of radiation, however, we are dependent upon the research programs of other agencies, partic-ularly programs of the Department of Energy and the National Institutes of Health. We have found our participation in the Interagency Radiation Research Committee, chaired by the Assistant Secret &ry of Health, Department of Health and Human Services (HHS) to be an effective means to coordinate the Federal research programs addressing the biological effects of ionizing radiation and to acquire knowledge of the totality of research being conducted and planned.
Specific ongoing and planned regulatory research activities in these areas include the following:
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(1) Occupational ALARA means efforts to maintain worker dose at levels which are as low as reasonably achievable.
Research projects planned in this effort include:
- an evaluation of various techniques for the safe removal (decontamination) of radioactive corrosion products from nuclear reactor systems so as to reduce ambient radiation levels in the working environment;
- an evaluation of occupational dose reduction opportunities at LWRs through the use of low-maintenance reactor components;
- an evaluation of extensive use of remote in-plant handling metheds for processing LWR radioactive wastes.
(2)
Improvement of health physics measurements can facilitate worker protection by providing better information concerning the hazard levels a-in the work place.
Research projects planned in this area include:
- an evaluation of radiological air-sampling methodology with the objective of providing guidance on, preferred methods;
- a study to establish regulatory performance standards for radiation survey instruments;
- evaluation and development of criteria for accrediting personnel dosimeter processors and bioassay laboratories;
- research in improved beta and neutron radiation measurement methods.
(3)
Internal dose control is increasingly important in view of recent recommendations to limit the combined external and internal dose to 5 rems per year, and new international guidance on internal dose calcu-lation methodology.
Research projects planned in this area include:
- research to develop computational methods for converting bioassay results to radionuclide intake as needed for assessing compliance with regulatory limits;
- the continuation of an extensive program in improvement of respiratory protection equipment and technical evaluation of newly de: eloped protective devices;
- research to establish regulatory guidance on bioassay methods and metabolic models for selected radionuclides.
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(4)
Evaluation of TM1 and the recent nuclear reactor health physics appraisal program indicated that performance of radiation protection personnel should be improved.
Projects in this area include:
- a job-skills analysis for power plant health physics technicians which will establish minimum qualifications for technicians and criteria for the improvement of training programs;
- development of guidance on minimum qualifications for radiation safety officers.
(5) The only effective way to control the collective dose is to reduce dose rates, working times, or both.
Projects planned in this area include:
- an analysis of radioactive torrosion product buildup and development of safe methods for removal in an effort to reduce dose rates;
- the conduct of studies which permit the selection of radiation protection procedures that will balance the financial cost with the health effects detriment.
(6)
Licensing improvement refers to providing guidance to applicants regarding the information that they must submit about their radiation protection programs.
Efforts in this area include.a series of regulatory guides for various types of operations.
(7) The health effects program concentrates its efforts on determining the health impact from the point of intake in or exposure to the human body through the estimates of risk of illness or disease.
In determining the health impacts the program assesses metabolic behavior of radionuclides and internal dosimetry of the exposed organs and tissues, and examines the various human factors that influence the effect, such as age, sex, dose rate, etc.
Both human and animal data are collected and evaluated.
At the present time our research program is addressing regulatory questions of the toxicity of neutrons and gamma rays; metabolism and toxicity of uranium, thorium, plutonium, and neptunium; early morbidity and mortality estimates for nuclear accidents; and with HHS the effects of low-level exposures to radioactive iodine.
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OUESTION 7.
To what do you attribute the increase in worker exposure?
ANSWER.
The increase in occupational radiation exposure at commercial nuclear power plants results primarily from routine maintenance and special maintenance as opposed to other routine activities such as reactor operation and surveillance, waste processing, etc.
Fo pressurized water reactors (PWR's), the major contributors to occupational doses have been steam generator inspection, maintenance and repair, including steam generator replacement and tube sleeving efforts.
Also, seismic hnger and snubber inspections and repairs have recently become significant soJrces of dose.
For boiling water reactors (BWR's), the major increase in occupatiorial dose is attributable to torus modifications, repairs related to stress corrosion cracking of pipes, seismic hanger and snubber inspections and repair, and changes to upgrade fire protection systems.
These major contributors to occupational doses have resulted primarily from unanticipated premature failure of major equipment or from recognition of need for equipment improvements.
QUESTION 7, (a) Has the NRC prepared studies to determine projected levels of worker exposure?
ANSWER.
Although we have not sponsored specific studies to project doses, there are several staff actions.in which projected levels of worker doses are determined.
The NRC staff requires each power reactor license applicant to provide projected worker doses in their Safety Analysis Reports which cover several work categories, including construction (i.e., on a site where a nuclear power unit is already operating), reactor operations and surveillance, routine maintenance, inservice inspection, special maintenance, waste processing, and refueling.
The NRC staff reviews these subnittals and prepares the Safety Evaluation Reports and Environmental Impact Statements.
l Additionally, when nuclear power reactor licensees submit requests for amendments which involve significant worker doses (e.g., for reactor coolant
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system repairs), the NRC staff evaluates the proposed task to assure that the methods and projected worker doses will be ALARA (as low as reasonably l
achievable).
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i The NRC has prepared studies to determine the sources of worker doses I
associated with steam generator maintenance, inspection, repair, removal, and replacement.
These studies are derived frpm actual operations and provide dose information which is typically task-related (e.g., removal of man-way covers, tube plugging, sludge lancing).
The studies are intended to help in the planning of related operations.
Summaries of recent studies are containted in NUREG/CR-1595, " Radiological Assessment of Steam Generator Removal and Replacement", (PNL, December 1980), and NUREG-0866, " Steam Generator Tube Experience" (February 1982).
The NRC report, NUREG-0713, " Occupational Radiation Exposure at Commercial Nuclear Power Peactors", a copy of which is enclosed, provides a year-to-year assessment of doses at power reactors. NUREG-0713 provides specific information which enables the Staif to assess and project doses for workers.
This includes an annual determination of the average dose for all occupationally exposed workers, the average dose per worker per reactor facility, average dose per PWR and BWR worker, the number of individuals in specified exposure ranges, annual collective doses by work function and personnel type, and an annual overexposure summary.
QUESTION 7.
(b) Assuming that steam generator tube repairs account in large part for the recent increase in worker exposure, what specific guidelines has the NRC distributed to utilities replacing or repairing steam generators to ensure the lowest reasonably achievable exposure levels?
ANSWER.
The NRC Staff has prepared and issued NUREG-0886, " Steam Generator Tube Experience" in February of 1982.
This document includes exposure reduction techniques which provide ALARA dose guidance specifically oriented to steam generator associated tasks.
It additionally provides a summary of occupational radiation exposure data derived from recent pressurized water. steam generator inspection and repair experience.
Other NRC guidance which has been published includes Regulatory Guide 8.8, "Information Relevant to Ensuring That Occupational Radiation Exposures at Nuclear Power Stations Will Be As Low As Is Reasonably Achievable" (June 1978), and draf t NUREG-0761, " Radiation Protection Plans for Nuclear Power Reactor Licensees" (March 1981).
These documents provide standards, criteria, and guidelines for integrating ALARA concepts into power reactor design and operations, including maintenance and any tasks involving occupational exposure.
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OUESTION 7.
(c) Does the NRC foresee problems of this type occurring for other repairs or retrofits?
ANSWER Yes - recurring and additional problems calling for repairs and retrofits are anticipated.
Steam generator tube degradation at PWR's will continue to. be a problem for the inmediate future.
The NRC Staff is presently pre-paring criteria which will increase the amount of inservice inspection (ISI) required for steam generators.
Both the ISI and associated repair effort will probably cause increased total doses to workers.
At BWR's, the pipe cracking problem may continue until efforts are complete and control measures impl emented. BWR torus modifications should be generally complete in '"1e coming year (1982).
Other modifications required as a result of the ThI accident, such as reactor vessel inventory measurement systems, may also result in increased doses to workers during the next few years, i
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NUREG-07'i3 Vol. 2 n
uccuaa:iona Rac.,.la: Ion Ex30sure at l
Comme cia
\\ uc ear 3 ower Reac' ors 1980 Annual Report U.S. Nuclear Regulatory Commission Office of Management and Program Analysis B. G. Brooks l
l Attachment Question 7.a.
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QUESTION 8.
Does the NRC review for completeness and accuracy the training sessions for nuclear " jumpers" conducted by licensees?
Please provide the Subcommittee all policy guidance provided.to licensees on this subject and a description of its review of these training programs.
ANSWER Yes', the NRC reviews the training programs conducted by the licensee for radiation protection of all workers, transient as well as employees.
The licensee provides a description of his : raining and retraining progra?s in the Final Safety Analysis Report, Section 12, which is reviewed by the NRC staff in accordance with the Standard Review Plan.
The Technical Specifications of the Facility License also contain a requirement for a training / retraining program in Section 6.4 The regulations require the licensees to keep all individuals working in or frequenting ar.y portion of a restricted area informed and instructec on radiation protection oroblems (10CFR Part 19)
NRC Inspection
- rocedures recuire that the licensee ra
- iation protection program, which includes training and retraining of transients and employees, be inspected by the resident inscector as well as the regional radiation specialists.
These inspection ecmirements are contained in the IE Manual Procedures 41700, " Training;"
71?CS, " Inspection During Long Term Shutdown;" 71700, " Operational Safety Verification;" and 83741, " Radiation Prctection-Operation." NRC staff guidance is rovided licensees through Regulatory Guides 1.S, " Personnel Qualification and Training" and E.27, " Radiation Protecticn Training For Perscnnel at Light-Water-Cooled Nuclear Power Plants." Further guidance, which is acceptable to the HRC staff, for the licensee is included in ANSI /ANS 3.1-1981, " Selection, Qualification and Training of Personnel for Nuclear Power Plants."
The NRC undertook a major effort to analyze the radiation protection programs at 48 commercially operated nuclear power plants, This. effort, called the Health Physics Appraisal Program, was initiated to determine whether the nuclear power plants had adequate radiation protection programs and whether they had incorporated the lessons learned from the TMI accident in the area of. radiation protection.
The results of the 48 appraisals have been addressed in NUREG-0855, " Health Physics Appraisal Program." The appraisals in the training / retraining area of radiation protection observed some good programs and some peer programs.
A significant effort is' underway at all nuclear power plants to improve the training for transients and employees in radiation protection and these efforts will continue to be monitored by the NRC through its inspection program.
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QUESTION 9.
Does the NRC promulgate maximum cumulative exposure' limits for each licensee?
If not, why not?
If so, what sanctions are available to the NRC in the event such limit is exceeded?
ANSWER.
The NRC has not established regulatory limits for cumulative exposures for licensees.
Currently, exposure limits for individual workers result in a small average risk, and establishing and enforcing cumulative limits would be difficult and costly because of differing conditions and operational needs at the various power plants.
However, efforts are underway to control exposures to levels that are as-low-as-reasonably-achievable (ALARA), which are well below current limits.
The staff is working on a proposed change to Commission regulations that would improve implementation of the ALARA concept for occupational exposures by making such implemen-tation inspectable and enforceable. The staff is also developing a cooperative agreement with the nuclear utilities's " Institute for Nuclear Power Operations" which will include controlling cumulative exposure.
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