Regulatory Guide 8.19

Rev 1 Occupational Radiation Dose Assessment in Light-Water Reactor Power Plants Design Stage Man-Rem Estimates

ML003739550
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Issue date:	06/30/1979
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RG-8.19 Rev 1
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Revision 1 U.S. NUCLEAR REGULATORY COMMISSION June 1979 REGULATORY GUIDE

OFFICE OF STANDARDS DEVELOPMENT

REGULATORY GUIDE 8.19 OCCUPATIONAL RADIATION DOSE ASSESSMENT

IN LIGHT-WATER REACTOR POWER PLANTS

DESIGN STAGE MAN-REM ESTIMATES

A. INTRODUCTION

forming an assessment of collective occupational radiation dose as part of the ongoing design Section 50.34, "Contents of Applications; review process involved in designing a light Technical Information," of 10 CFR Part 50, water-cooled power reactor (LWR) so that

"Licensing of Production and Utilization Facil occupational radiation exposures will be ities," requires that each applicant for a permit ALARA.

to construct a nuclear power reactor provide a preliminary safety analysis report (PSAR) and that each applicant for a license to operate

B. DISCUSSION

such a facility provide a final safety analysis report (FSAR). Section 50.34 specifies in The dose assessment process requires a good general terms the information to be supplied in working knowledge of (1) the principal factors these reports. contributing to occupational radiation expo A more detailed description of the information sures that occur at a nuclear reactor power needed by the NRC staff in its evaluation of plant and (2) methods and techniques for applications is given in Regulatory Guide 1.70, ensuring that the occupational radiation expo Revision 3, "Standard Format and Content of sure will be ALARA.

Safety Analysis Reports for Nuclear Power Plants." Section 12.4, "Dose Assessment," of In assessing the collective occupational dose Regulatory Guide 1.70, Revision 3, states that at a plant, the applicant evaluates each poten the safety analysis report should provide the tially significant dose-causing activity at that estimated annual radiation exposure to person plant (i.e., activities that result in greater than one man-rem per year). The applicant

• nel at the proposed plant during normal opera tions. The man-rem estimate requirement is an specifically examines such things as design, important part of the overall, ongoing radiation shielding, plant layout, traffic patterns, protection design review. The purpose of this expected maintenance," and radioactivity requirement is to provide that adequate sources. This evaluation process is aimed at detailed attention is given during the prelimi the consideration of eliminating unnecessary nary design stage (as described in the PSAR), exposures, minimizing foreseen required doses as well as during construction after completion (individual and collective), and examining the of design (as described in the FSAR), to dose cost-effectiveness of each dose-reducing meth causing activities to ensure that personnel od and technique. This evaluation process and exposures will be as low as reasonably achiev the dose reductions that may be expected to able (ALARA). The safety analysis report pro result are the principal objectives of the dose vides an opportunity for the applicant to assessment. The dose assessments prepared in demonstrate the adequacy of that attention and accordance with this guide are intended for use to describe whatever design' and procedural as an aid in what should be a continuing search chahges have resulted from the dose assess for dose-reducing techniques and not for NRC

ment process. regulatory enforcement purposes.

The objective of this guide is to describe a The principal benefits arising from this eva method acceptable to the NRC staff for per luation process occur during the period of pre liminary design since many of the ALARA prac Lines indicate substantive changes from previous issue.

tices are part of the design process. On the USNRC REGULATORY GUIDES Commento ahud be aunt to di Secrawy of Oe Coma.nion, U.S. Nucer Regbtor, Guideq am issued ID decrb and* rok-, rmilebe to fte pubk Regubtory Cn-ntmmio.n, Waihington, D.C. 2 Service Branch. , Attention: Dockeft0 ars maldiod captsibleo ftONRC Wl of , - pn, wt of thne Cormn iaona regul*aon to d" %leeclmiqu umd by fe stiff in eawu- The guides areWled In fte flowng ton broad dhtalon:

L FA", pro ns or POstulAtd cdn. or to provide guidanco to Gukdn we ro subetkutes for regubmora, ad eorn- 1. POVW Reaictors 6. Products P1Kmcewflh dn is not requed. Methode and aolutlons iffaMrnt from tioee 2. Reewch and Teat Rmctor ea out I dn quldee wl be acceptable ff they provide a beal for fte idge 7. Treplortation raque to dihenue

3. Fu and MeRaNW

ins Fact & Occupationel Inhld m or condinumce of a peri or kern by dte 4. EnroM nenw and Sttig 9. Antitrust and Financial Review Conunlelon 5. MPa lIs and Plant Protectioi 10. General R qued a for age cop*es of inued gude (which nay be rprodu or for Convrdtnw and sn gest.or, forl-ipr , ntes in dine guides are, enouragd at pcmnt WChnintont D.C. tat r c of future guides sl times and guidee will be rewbee,n approprite to accomodat Iomet inapcfic I =iln a=uW be aein wrtn oteU.S. Nuclear Regulatory and to ~refetnw ioonormato or emperlec.Tegie rvade ei Comnimaon, Waatibigton, D.C. 2050, Attenrtion: Dkactor, Division of of VAubeiv covnueta reoivdfo i ui ndaiinlae eiw Tedwilalinfrm~rration and Document Control.

other hand, additional benefits can also accrue dose assessment include steam generator tube during advanced design stages and even dur plugging and maintenance, repairs, inservice ing early construction stages, as better evalu inspection, and replacement of pumps, valves, ation of dose-causing operations are available and gaskets. Doses from nonroutine activities and further design refinements can be identi that are anticipated operational occurrences fied. In addition, operations that will need should be included in the applicant's ALARA

special planning and careful dose control can dose analysis. Radiation sources and personnel be identified at the preoperational stage when activities that contribute significantly to occu the applicant can take advantage of all design pational radiation exposures should be clearly options for reducing the occupational dose. identified and analyzed with respect to similar exposures that have occurred under similar C. REGULATORY POSITION conditions at other operating facilities. In this manner, corrective measures can be incorpora This guide describes the format and content ted in the design at an early stage.

for assessments of the total annual occupational (man-rein) dose at an LWR--principally during Tables 1 through 8 are examples of work the design stage. The dose assessment at this sheets for tabulation of data in the dose stage should include estimated annual assessment process to indicate the factors con personnel exposures during normal operation sidered. The actual numbers used in the tabu and during anticipated operational occur lations will depend on plant-specific information rences. It should include estimates of the fre developed in the course of the dose assessment quency of occurrence, ,the existing or resulting review.

radiation levels, the manpower requirements, and the duration of such activities. These esti An objective of the dose assessment process mates can be based on operating experience at should be to develop similar plants. However, to the extent possible, estimates should include consideration 1. A completed summary table of occupa of the design of the proposed plant, including tional radiation exposure estimates (such radiation field intensities calculated on the as Table 1),

basis of the plant-specific shielding design, taking into account the effect of any dose 2. Sufficient illustrative detail (such as that reducing design changes. shown in Tables 2 through 8) to explain how the radiation exposure assessment The dose assessment process and the con process was performed, comitant dose reduction analysis should involve individuals trained in plant system design, 3. A systematic process for considering and shield design, plant operation, and health evaluating possible dose-reducing design physics. Knowledge from all these disciplines changes and associated operating proce should be applied to the dose assessment and dure changes as part of the comprehen to the entire radiation protection design review sive ongoing design review, and in determining cost-effective dose reductions.

4. A record of the rievidw procedures, Plant experience provides useful information documentation requirements, and identi on the numbers of people needed for jobs, the fication of principal ALARA-related duration of different jobs, and the frequency changes resulting from the dose assess of the jobs as well as on actual occupational ment. This record should be included in radiation exposure experience. The applicant the assessment as a demonstration of the should use personnel exposure data for specific steps taken to ensure exposures will be kinds of work and job functions available from ALARA.

similar operating LWRs.* Useful reports on these data have been published by the Atomic During the final design stage, dose assess Industrial Forum, Inc. and the Electric Power ment should be updated to take into account Research Institute, and a summary report on any major design changes. In particular, com occupational radiation exposures at nuclear pleted shielding design and layout of equipment power plants is distributed annually by the should permit better estimates of radiation field Nuclear Regulatory Commission. intensities in locations where work will be per formed.

The occupational dose assessment should include projected doses during normal opera Analysis of the elements of the man-rem esti tions, anticipated operational occurrences, and mate (e.g., radiation levels, task duration, shutdowns and should be based on anticipated and frequency), treated qualitatively, can be radiation conditions after at least 5 years of of significant value in making engineering plant operation. Some of the exposure-causing judgments regarding design changes for activities that should be considered in this ALARA purposes. As a result of the dose assessment process described herein, it is to

• See Regulatory Guide 1.16, "Reporting of Operating Infor be expected that various dose-reducing design mation--Appendix A Technical Specifications," for exapleo Of changes and innovations will be incorporated work and job functin. into the design.

8.19-2

The precision of the man-rem estimate is of

D. IMPLEMENTATION

secondary importance. That estimate's relation ship to actual man-rem doses received during subsequent plant operation will depend pri The purpose of this section is to provide in marily on operating experience and maintenance formation to applicants regarding the NRC

and repair problems encountered rather than staff's plans for using this regulatory guide.

on design projections, however precise.

Entries in the tables should be identified and their basis explained in the text of the report, This guide reflects current NRC staff prac e.g., available data from similar plants, tice. Therefore, except in those cases in which expected (reduced) values due to design, and the applicant proposes an acceptable alterna engineering improvements. Such information tive method for complying with specified por will readily identify those areas in which tions of the Commission's regulations, the ALARA efforts are to be made or have been method described herein is being and will con made. Additionally, it would be of value to tinue to be used in the evaluation of submittals indicate whether the reduced values in appli in connection with applications for construction cable cases were derived on the basis of permits or operating licenses until this guide is physical (or other) models. This would alert revised as a result of suggestions from the individuals concerned with the analysis of the public or additional staff review. For construc occupational radiation dose assessment report tion permits, the review will focus principally in determining whether the well-intended im on design considerations; for operating provements are productive or counterproduc licenses, the review will focus principally on tive. administrative and procedural considerations.

8.19-3

TABLE 1 TOTAL OCCUPATIONAL RADIATION EXPOSURE

ESTIMATES

Dose Activity (man-reins/year)

Reactor operations and surveillance (see Tables 2 & 3)

Routine maintenance (see Table 4)

Waste processing (see Table 5)

Refueling (see Table 6)

Inservice inspection (see Table 7)

Special maintenance (see Table 8)

Total man-reins/year Occupational exposures from Tables 2 through 8 are entered in Table 1 and added to obtain the facility's estimated total yearly occupational dose.

8.19-4

TABLE 2 OCCUPATIONAL DOSE ESTIMATES DURING ROUTINE OPERATIONS AND SURVEILLANCE

Average Exposure Number of Number of Dose workers events (man-rems/year)

dose rate time per Utility Contractor per year Utility Contractor Activity (mrem/hr) event (hr)

Walking in radiation zones Checking systems and equipment:

Containment cooling system Boron acid (BA) makeup system Fuel pool system Control rod drive (CRD) system Other systems (specify):

1! Pumps:

CRD

Residual heat removal Accumulators Pressurizer valves Other equipment (specify):

- + -

. Total

• The list of activities is for illustrative purposes only, is not all inclusive, and would be expected to vary from plant to plant.

TABLE 3 OCCUPATIONAL DOSE ESTIMATES DURING NONROUTINE OPERATION AND SURVEILLANCE

Average Exposure Number of Number of Dose dose rate time per workers events (man-rems/year)

Activity (mrem/hr) event (hr) Utility Contractor per year Utility Contractor Operation of systems equipment:

Safety injection system Feedwater pumps & turbine Instrument calibration Other (specify):

Collection of radioactive samples:

00

cO

Liquid

!

Gas Solid Radiochemistry Radwaste operation Health physics Other (specify):

- + =

Total The list of activities is for illustrative purposes only, is not all inclusive, and would be expected to vary from plant to plant.

TABLE 4 OCCUPATIONAL DOSE ESTIMATES DURING ROUTINE MAINTENANCE

Average Exposure Number of Number of Dose dose rate time per workers events (man-reins/year)

Activity (mrem/hr) event (hr) Utility Contractor per year Utility Contractor Changing filters:

Waste filter Laundry filter Boron acid filter Pressure valves BA makeup pump o* BA holding pump Instrumentation and controls:

Transmitter inside containment Transmitter outside containment Radwaste processing system Other (specify):

Total

- + -

• The list of activities is for illustrative purposes only, is not all inclusive, and would be expected to vary from plant to plant.

TABLE 5 OCCUPATIONAL DOSE ESTIMATES DURING WASTE PROCESSING

Average Exposure Number of Number of Dose (man-rems/year)

time per workers events dose rate Utility Contractor event (hr) Utility Contractor per year Activity (mrem/hr)

Control room Sampling and filter changing Panel operation, inspection and testing Operation of waste processing and packaging equipment Other (Specify):

- + -

I Total OO

• The list of activities is for illustrative purposes only, is not all inclusive, and would be expected to vary from plant to plant.

I

TABLE 6 OCCUPATIONAL DOSE ESTIMATES DURING REFUELING

Average Exposure Number of Number of Dose

, dose rate time per workers events (man-reins/year)

Activity (mrem/hr) event (hr) Utility Contractor per yearl Utility Contractor Reactor pressure vessel head and internals- removal and installation - - -

Fuel preparation - - - - -

Fuel handling - - - - -

Fuel shipping - - - - -

Other (specify): - - - -

?D Total - - - + =

CD

I

The list of activities is for illustrative purposes only, is not all inclusive, and would be expected to vary from plant to plant.

Most work functions performed during refueling, and the associated occupational dose received, will vary depending on facility design (BWR or PWR), reactor pressure vessel size, and number of fuel assemblies in the reactor core. For a detailed description of pre-planned activities, time, and manpower schedule, refer to the "critical path for refueling tasks," which should be available from the Nuclear Steam Supply System (NSSS) supplier.

TABLE 7 OCCUPATIONAL DOSE ESTIMATES DURING INSERVICE INSPECTION

Exposure Number of Number of Dose Average dose rate time per workers events (man-reins/year)

event (hr) Utility Contractor per year Utility Contractor Activity (mrem/hr)

Providing access: installation of platforms, ladders, etc.,

removal of thermal insulation Inspection of welds Follow up: installation of thermal insulation, platform removal, and cleanup

+ - =

Total and would be expected to vary from plant to plant.

0 *The list of activities is for illustrative purposes only, is not all inclusive, Variations are expected as a consequence of reactor Estimates should be based on average yearly values over a 10-year period. automation available for remote examination of equipment size, design, number of welds to be inspected yearly, and the degree of welds.

I

TABLE 8 OCCUPATIONAL DOSE ESTIMATES DURING SPECIAL MAINTENANCE

Average Exposure Number of Number of Dose dose rate time per workers events Activity (man-rems/year)

(mrem/hr) event (hr) Utility Contractor per year Utility Contractor Servicing of control rod drives Servicing of in-core detectors Replacement of control blades Dechanneling of spent and channeling of new fuel assemblies Steam generator repairs I

I-. Other (specify):

Total

- + - =

The list of activities is for illustrative purposes only, is not all inclusive, and would be expected from plant to plant. to vary significantly Most preplanned (or routine) maintenance activities during outage are described in the which should be available from the NSSS supplier, and are "critical path for refueling tasks,"

performed in parallel with the critical path refueling tasks shorten reactor outage tim

e. to

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