ML20062B145
| ML20062B145 | |
| Person / Time | |
|---|---|
| Issue date: | 04/22/1982 |
| From: | Harold Denton Office of Nuclear Reactor Regulation |
| To: | Bassett H NRC OFFICE OF MANAGEMENT AND PROGRAM ANALYSIS (MPA) |
| References | |
| NUDOCS 8208040347 | |
| Download: ML20062B145 (8) | |
Text
.
APR 2 2 $82 MDiORANDUM FOR: Harold S. Bassett, Acting Director Office of Managenent and Program Analysis FROM:
Harold R. Denton, Director Office of Nuclear Reactor Regulation
SUBJECT:
GREEN TICKET 11762 - OTTINGER QUESTIONS Attached are the NRR responses to the questions posed by Representative Richard L.
Ottinger and forwarded in your note of April 14, 1982.
This response was prepared by R. J. Serbu of the Radiation Protection Section, RAB DSI, NRR.
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Harold R. Denton, Director Office of Nuclear Reactor Regulation
Attachment:
Response to Questions RIBUTION:
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s 7.
To what do you attribute the increase in worker exposure?
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, and in-service inspection of equipment.
For pressurized water reactors (PWR's), the major contribute to occupational dose have been steam generator inspection, maintenance and repair, including steam generator replacanent and tube resleeving efforts. Seismic hangar and snubber inspections and repairs have recently become significant source of dose.
For boiling water reactnrs (BWR's), the major increase in occupational dose is attributable to torus modifications, repairs related to stress corrosion cracking of pipes, seismic hangar and snubber inspections and repair, and changes to upgrade fire protection systems.
These major contributors to occupational doses have resulted primarily from unanticipated prenature failure of major equipment or from recognition of need for equipment improvenents.
7a. Has the NRC prepared studies to determine projected levels of worker exposure?
l i
Although we have not sponsored specific studies to project doses, there are l
l several staff actions in which projected levels of worker doses are deter-mined. 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 maintenarce, waste processing, and refueling.
The NRC staff reviews these submittals and prepares the Safety Evaluation Reports and Environmental Impact Statements.
l
. Additionally, when nuclear power reactor licensees submit amendment requests which involve significant worker doses (e.g., for reactor coolant 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 achieva bl e).
The NRC has prepared studies to determine the sources of worker doses associated with steam generator maintenance, inspection, repair, removal, and replacement. These studies are derived from actual operations and provide dose information which is typically task-related (e.g., removal of manway covers, tube plugging, sludge lancing). The studies are intended to help in the planning of related operations. Summaries of recent studies are contained 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 a? Commercial Nuclear Power Reactors", 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 Staff 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.
\\ 7b. 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?
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 i
exposure.
7c. Does the NRC foresee problems of this type occurring for other repairs or retrofits?
l 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 immediate future. The NRC Staff is presently preparing I
l I criter$a which will increase the amount of inservice inspection (ISI) required for steam generators. Both the ISI and associated repair effort will probably caus'e jncreased ' total doses to workers. At BWR's, the pipe cracking problem may continue.until repair efforts are complete and control measures impl enen ted. BWR-torus modifications should be generally complete in the i
coming year (1982).
Other modifications required s a result of the TMI accident, such as reactor vessel inventory measuronent systens, will result in doses to workers in the next fw years.
However, we have not quantified these doses resulting from such modifications because they will vary depending on specific plant conditions.
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" COT April 9, 1982' The~Eonorable Hunzio P..adino Chairman Nuclear Regulatory Commission Washington, D.C.
20555
Dear Hr. Chairman:
In its Annual Report to tongress entitled " Review and Evaluation of the Nuclear Regulatory Commiccion Safety Reccarch Program for Fiscal Year 1983," the ACRS noted the rapid increase in cumulative occupational exposure associated with the operation, maint~enance and modification of commercial nuclear power plants.
The report chates:
"Whereas a few years ago, the generally accepted value f.or a single power plant was about 500 person-ren per year, the latest tabulation published by the NRC chowed that the average collective doce per operating unit increased by 33 percent between 1979 and 1980 and now approximatec 790 person-rem per
- year, projections are that some individual plants will have collective doses of as much ac 5,000 parcon-rem for 1982."
In view of occupational expocure increaccc of this magnitude and the incroacing number of workers who have been and will be expoced, please respond to the following questions on or before April 29, 1982.
M c the NRC maintain, or ry uire its licenses to g.j,{ { f @1.
tpainta_in, complete exp_osure records for all workers in radioactive portions of a' nuclear facility?
2 Does NRC maintain a " tracking" c tem for licensecc to 4
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ensure against overexposure o Fi iVidual workers who
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may work at more than one nuclear facility?
u h h 3.
Docc the HRC maintain, or require its licencees to maintiain, a screening procecc to determine whether an u__.
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The Honorable Nunzio Palladino Apri1~9, 1982 Page 2 applicant has worked.or been exposed at any other nuclear facility or has exceeded his or her exposure limit at the same nuclear facility?
4.
Does the NRC maintain, or require its licensees to 2_
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maintain,_long-term health _r_ec_ords of employees who have r
been radiologically exposed to determine long-term health effects of ionizing radiation?
M R What activities does the NRC conduct in conjunction with 5'
the Transuranto R_csis.te If none curreneir, have there been such activities in_r?
the past?
Is the NRC considering instituting or reinstituting'its participation in the Register?
If not, why not?
6.
Please describe in sufficient detail each program referred to and numerically identified in the fo11oving
{~ C excerpt from the ACRS report previously cited.
"We are encouraged to note that the NRC has recognized the importance of this problem and has Qga completed (1) initial steps for developing a comprehensive research_ prog, ram for addressing the associated regulatory needs.
We are encouraged also to'see the (2) related research activities that have been developed to fT11NidsTi'n the-
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regulatory aspects of a wfde variety of problems associated with the protection of workers at nuclear facilities."
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Has the NRC prepared studies to deterime projecte,d :
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levels of worker exposure?
b.
Assuming that steam generator tube repairs account in large part for the recent increase in worker
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exposure, what s_pecific guidelines has the NRO
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steam generators to ensure the lowest reasonably ' og' t
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Does the NRC foresee problems of this type c.
occurring for other repairs or retrof_its?
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s The Ilonorablo Nunzio Palladino April 9, 1982 Page 3 8.
Does the NRC review for completeneds and accuracy the
^ TE trainiris sessions for nucicar jungers conductea hy Please provide the subcoHmittee all policy flcensees?
guidance provided to licensees on this subject and a description of its review of'these training programs.
9.
Does the NRC promul. gate may.imum cumulativo cxposurg limits for eacMice35B?
If7fot, why notif If so, what
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sc.nctions are available to the NRC' in the event such limit is exceeded?
Sincerely,
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APR 2 21982 MENORANDUM FOR: Harold S. Bassett, Acting Director Office of Managenent and Program Analysis FROM:
Harold R. Denton, Director Office of Nuclear Reactor Regulation
SUBJECT:
GREEN TICKET 11762 - OTTINGER QUESTIONS Attached are the NRR responses to the questions posed by Representative Richard L.
Ottinger and forwarded in your note of April 14, 1982.
This response was prepared by R. J. Serbu of the Radiation Protection Section, RAB, DSI, NRR.
Harold R. Denton, Director Office of Nuclear Reactor Regulation
Attachment:
Response to Questions
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a.
7.
To what do you attribute the increase in worker exposure?
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, and in-service inspection of equipment.
For pressurized water reactors (PWR's), the major contribute to occupational dose have been steam generator inspection, maintenance and repair, including steam generator replacmert and tube resleeving efforts. Seismic hangar and snubber inspections and repairs have recently become significant source of dose.
For boiling water reactors (BWR's), the major increase in occupational dose is attributable to torus modifications, repairs related to stress corrosion cracking of pipes, seismic hangar and snubber inspections and repair, and changes to upgrade fire protection systems.
These major contributors to occupational doses have resulted primarily from unanticipated praature failure of major equipment or from recognition of need for equipment improvements.
7a.
Has the NRC prepared studies to determine projected levels of worker exposure?
Although we have not sponsored specific studies to project doses, there are several staff actions in which projected levels of worker doses are deter-i mined. The NRC staff requires each power reactor license applicant to provide projected worker doses in their Safety Analysis Reports which cover i
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 submittals and prepares the Safety Evaluation Reports and Environmental Impact Statements.
a
. Additionally, when nuclear power reactor licensees submit amendment requests which involve significant worker doses (e.g., for reactor coolant 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 achieva bl e).
The NRC has prepared studies to determine the sources of worker doses associated with steam generator maintenance, inspection, repair, removal, and replacement. These studies are derived from actual operations and provide dose information which is typically task-related (e.g., removal of manway covers, tube plugging, sludge lancing). The studies are intended to help in the planning of related operations. Summaries of recent studies are contained 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 Reactors", a copy of which is enclosed, provides a year-to-year assessment of doses at power reactors.
NUREG-0713 provides :pecific i
information which enables the Sta'ff 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.
7-O
. 7b. 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?
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 draft 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.
7c.
Does the NRC foresee problems of this type occurring for other repairs or retrofits?
Yes - recurring and additional problems calling for repairs and retrofits are anticipa ted. Steam generator tube degradation at PWR's will continue to be a problem for the immediate future. The NRC Staff is presently preparing
. 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 repair efforts are complete and control measures impl emented. BWR torus modifications should be generally complete in the coming year (1982).
Other modifications required as a result of the TMI accident, such as reactor vessel inventory measurenent systems, will result in doses to workers in the next few years.
However, we have not quantified these doses resulting from such modifications because they will vary depending on specific plant conditions.
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The'Eonorable Nunzio Palladino Chairman nuclear negulatory Commiscion Washington, D.C.
20555
Dear Hr. Chairman:
In itc Annual Report to tongress entitled " Review and Evaluation of the Nuclear Regulatory Commission Safety Recearch Program for Fiscal Year 1983," the ACRS noted the rapid increase in cumulative occupational exposure associated with the operation, maint~enance and modification of commercial nuclear power plants.
The report ctates:
"Whereas a few years ago, the generally accepted value f.or a single power plant was about 500 person-rem per year, the latest tabulation published by the NRC chowed that the average collective doce par operating unit increaced by 33 percent between 1979 and 1980 and now approximates 790 person-rem per year.
Projections are that some individual plants will have collective doses of ac much ac 5,000 prcon-rem f or 1982. "
In view of occupational exposure increases of this magnitude and the increasing number of workers who have been and will be exposed, please respond to the following quentiens on or before April 29, 1982.
Does the NRC maintain, or r_eguire its Mcenses to
__ j jd{ f @1.
maintain, complete exposure records for all workers in Fadioactive portions'6f'a nuclear facility?
~
DoesNRCmaTntaina" tracking"__cstemforlicenseccto 4h 2
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ennure againct overexposure of i Tividual workers who may work at more than one nuclear. facility?
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Does the NRC maintain, or require its licenaces to maint'ain, a screening proceco to determine whether an g
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- r The Honorchle Nunzio Palladino April 9, 1982 Page 2 applicant has worked or been exposed at any other nucicar facility or has exceeded his or her exposure limit at the same nuc1 car facility?
4.
Does the DRC maintain, or require its licensees to
_,g' g maintai_n, long-term health __r_cc_o.rds of employees who have z_
been radiologically exposed to determine long-term health effects of ionizing radiation?
f4PR What activities does the NRC conduct in conjunction with 5'
the Transuranic Resister?
1f 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?
6.
Please describe in sufficient detail each program referred to and numerically identified in the fo11oving excerpt from the ACRS report previously cited.
{}C "We are encouraged to note that the NRC has recognized the importance of this problem and has Qc4 completed (1) initial steps for developing a comprehensive research_pr_ogram for addressing the associated regulatory needs.
We are encouraged also to see the (2) related research activities that have been developed to fi~l1 voids ~i~n~fhe--
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~
regulatory aspects of a wfde variety of prob 1 cms associated with the protection of workers at nuclear facilities."
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To what do you attribute the increase in workgy
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,xposure?
e Has the NRC prepared studies to deterime projecte,d:
a.
levels of worker exposure?
b.
Assuming that steam generator tube repairs account in large part for the recent increase in worker exposure, what s_pecific guidelines has the NRC-e distribute,d to ut'i1i~ ties rsp15Eing or WpEiring,"
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steam generators to ensure the lowest reasonably '. g" achievable exposure levels?
Does the NRC foresce probicos of this ' type c.
occurring for other reggirs or retrofits?
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The Ilonorable Nunzio Palladino April 9, 1982 Page 3 8.
Does the liRC review for completeness and accuracy the
.1E eriinirig. sessions for nuc1_ ear _.jum2ere conducted hy c
1Teensees?
Please provide the subconmittee all policy guidance provided to licensecs on this subject and a description of its review of these training programa,
~
Does the NRC promu1 gate maximum cumulative __exnosurs 1
9.
. d limits for eachj_icsH G ?
If liot, why not?
If so, what
[% F canctions are available to the NRC in the event such limit is exceeded?
Sincerely,
.Nll,*(t.{f
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,Richard L. Ottinger Chairman 1
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