NRC Generic Letter 1978-10
| ML031280377 | |
| Person / Time | |
|---|---|
| Issue date: | 04/11/1978 |
| From: | Goller K R Office of Nuclear Reactor Regulation |
| To: | |
| References | |
| GL-78-010 | |
| Download: ML031280377 (18) | |
49 REG Do°C M 7ETso UNITED STATESA iNUCLEAR REGULATORY COMMISSIONWASHINGTON, D. C. 20555 --April 11, 1978CgL- 22-4OTo All Power Reactor LicenseesGentlemen:Enclosed for your information and possible future use is the current NRCguidance on radiological environmental monitoring for nuclear power plants.10 CFR Parts 20 and 50 require that radiological environmental monitoringprograms be established to provide data on measurable levels of radiationand radioactive materials in the site environs. In addition, Appendix Ito 10 CFR Part 50 requires that the relationship between quantities ofradioactive material released in effluents during normal operation, includ-ing anticipated operational occurrences, and resultant radiation doses toindividuals from principal pathways of exposure be evaluated.Regulatory Guide 4.8, Environmental Technical Specifications for NuclearPower Plants, was issued for comment in December 1975. The enclosed tech-nical position on the radiological portion of environmental monitoring wasformulated by an NRC working group which considered the comments receivedon Regulatory Guide 4.8. This position sets forth guidance for developingan acceptable minimum radiological monitoring program to meet the regula-tory requirements of 10 CFR Parts 20 and 50. Local site characteristicsneed to be examined to determine if pathways not covered by this guide maysignificantly contribute to an individual's dose and shouldbe included inthe sampling program. The acceptability of changes to radiological environ-mental monitoring programs at operating reactors will be evaluated based onthis guidance as well as on a review of past operating data.We are developing technical specifications which incorporate the Appendix Iguidance set forth in the enclosed position. These specifications will beimplemented on all operating reactors in the future. This position is be-ing provided to you at the present time for information only and no actionis required on your part. More specific guidance on technical specificationsrelating to the implementation of Appendix I to 10 CFR 50 will be provided toyou in the future.Karl R. Goller, Assistant Directorfor Operating ReactorsDivision of Operating ReactorsOffice of Nuclear Reactor Regulation March 1978Branch Technical PositionBackgroundRegulatory Guide 4.8, Environmental Technical Specifications for NuclearPower Plants, issued for comment in December 1975, is being revised basedon comments received. The Radiological Assessment Branch has developedthe following Branch Position on the radiological portion of the environ-mental monitoring program. The position was formulated by an NRC workinggroup which considered comments received after the issuance of theRegulatory Guide 4.8.10 CFR Parts 20 and 50 require that radiological environmental monitoringprograms be established to provide data on measurable levels of radiationand radioactive materials in the site environs. In addition, Appendix I to10 CFR Part 50 requires that the relationship between quantities of radio-active material released in effluents during normal operation, includinganticipated operational occurrences, and resultant radiation doses to in-dividuals from principals pathways of exposure be evaluated. These pro-grams should be conducted to verify the effectiveness of in-plant measuresused for controlling the release of radioactive materials. Surveillanceshould be established to identify changes in the use of unrestricted areas(e.g., for agricultural purposes) to provide a basis for modifications inthe monitoring programs for evaluating doses to individuals from principalpathways of exposure. NRC Regulatory Guide 4.1, Rev. 1, "Programs forMonitoring Radioactivity in the Environs of Nuclear Power Plants," providesan acceptable basis for the design of programs to monitor levels of radia-tion and radioactivity in the station environs.This position sets forth an example of an acceptable minimum radiologicalmonitoring program.. Local site characteristics must be examined to determineif pathways not covered by this guide may significantly contribute to anindividual's dose and should be included in the sampling program...
AN ACCEPTABLE RADIOLOGICALENVIRONMENTAL MONITORING PROGRAMProgram RequirementsEnvironmental samples shall be to3lected and analyzed according to Table 1at locations shown in Figure 1.I1 Analytical techniques used shall besuch that the detection capabilities in Table 2 are achieved.The results of the radiological environmental monitoring are intended tosupplement the results of the radiological effluent monitoring by verifyingthat the measurable concentrations of radioactive materials and levels ofradiation are not higher than expected on the basis of the effluent measure-ments and modeling of the environmental exposure pathways. Thus, thespecified environmental monitoring program provides measurements of radiationand of radioactive materials in those exposure pathways and for those radio-nuclides which lead to the highest potential radiation exposures of indivi-duals resulting from the station operation. The initial radiological environ-mental monitoring program should be conducted for the first three years ofcommercial operation (or other period corresponding to a maximum burnupin the initial core cycle). Following this period, program changes may beproposed based on operational experience.The specified detection capabilities are state-of-the-art for routineenvironmental measurements in industrial laboratories. The LLDs for I-131in water, milk and other food products correspond to one-quarter of theAppendix I (10 CFR Part 50) design objective dose-equivalent of 15 mrem/yrfor atmospheric releases and 10 mrem/yr for liquid releases to the mostsensitive organ and age group. They are based on the assumptions givenin Regulatory Guide 1.109, Rev 1.Deviations are permitted from the required sampling schedule if specimensare unobtainable due to hazardous conditions, seasonal unavailability,malfunction of automatic sampling equipment and other legitimate reasons.If specimens are unobtainable due to sampling equipment malfunction,every effort shall be made to complete corrective action prior to theend of the next sampling period. All deviations from the sampling scheduleshall be documented in the annual report.The laboratories of the licensee and licensee's contractors which performanalyses shall participate in the Environmental Protection Agency's (EPA's)Environmental Radioactivity Laboratory Intercomparisons Studies (Crosscheck)Program or equivalent program. This participation shall include all of thelIt may be necessary to require special studies on a case-by-case andsite specific basis to establish the relationship between quantitiesof radioactive material released in effluents, the concentrations inenvironmental media, and the resultant doses for important pathway determinations (sample medium-radionuclide combination) that are offered byEPA and that also are included in the monitoring program. The results ofanalysis of these crosscheck samples shall be included in the annual report.If the results of a determination in the EPA crosscheck program (or equivalentprogram) are outside the specified control limits, the laboratory shallinvestigate the cause of the problem and take steps to correct it. Theresults of this investigation and corrective action shall be included inthe annual report.The requirement for the participation in the EPA crosscheck program, orsimilar program, is based on the need for independent checks on theprecision and accuracy of the measurements of radioactive material inenvironmental sample matrices as part of the quality assurance programfor environmental monitoring in order to demonstrate that the resultsare reasonably valid.A census shall be conducted annually during the growing season to determinethe location of the nearest milk animal and nearest garden greater than50 sq. meters (500 sq. ft.) producing broad leaf vegetation in each ofthe 16 meteorological sectors within a distance of 8 km (5 miles).2 Forelevated releases as defined in Regulatory Guide 1.111, Rev. 1., the censusshall also identify the locations of all milk animals, and gardensgreater than 50 sq. meters producing broad leaf vegetation out to adistance of 5 km. (3 miles) for each radial sector.If it is learned from this census that the milk animals or gardens are pre-sent at a location which yields a calculated thyroid dose greater than thosepreviously sampled, or if the census results in changes in the location usedin the radioactive effluent technical specifications for dose calculations,a written report shall be submitted to the Director of Operating Reactors,NRR (with a copy to the Director of the NRC Regional Office) within 30 daysidentifying the new location (distance and direction). Milk animal orgarden locations resulting in higher calculated doses shall be added to thesurveillance program as soon as practicable.The sampling location having the lowest calculated dose may then be droppedfrom the surveillance program at the end of the grazing or growing seasonduring which the census was conducted. Any location from which milk canno longer be obtained may be dropped from the surveillance program afterzBroad leaf vegetation sampling may be performed at the site boundaryin a sector with the highest D/Q in lieu of the garden censu notifying the NRC in writing that they are no longer obtainable at thatlocation. The results of the land-use census shall be reported in theannual report.The census of milk animals and gardens producing broad leaf vegetation isbased on the requirement in Appendix I of 10 CFR Part 50 to "Identifychanges in the use of unrestricted areas (e.g., for agricultural purposes)to permit modifications in monitoring programs for evaluating doses toindividuals from principal pathways of exposure." The consumption of milkfrom animals grazing on contaminated pasture and of leafy vegetation con-taminated by airborne radioiodine is a major potential source of exposure.Samples from milk animals are considered a better indicator of radioiodinein the environment than vegetation. If the census reveals milk animals arenot present or are unavailable for sampling, then vegetation must be sampled.The 50 sq. meter garden, considering 20% used for growing broad leaf vege-tation (i.e., similar to lettuce and cabbage), and a vegetation yield of2 kg/M2, will produce the 26 kg/yr assumed in Regulatory Guide 1.109,Rev 1., for child consumption of leafy vegetation. The option to considerthe garden to be broad leaf vegetation at the site boundary in a sectorwith the highest D/Q should be conservative and that location may be usedto calculate doses due to radioactive effluent releases in place of theactual locations which would be determined by the census. This optiondoes not apply to plants with elevated releases as defined in RegulatoryGuide 1.111, Rev. 1.Reporting RequirementA. Annual Environmental Operating Report, Part B, Radiological.A report on the radiological environmental surveillance program forthe previous calendar year shall be submitted to the Director of theNRC Regional Office (with a copy to the Director, Office of NuclearReactor Regulation) as a separate document by May 1 of each year.The period of the first report shall begin with the date of initialcriticality. The reports shall include a summary (format of Table 3),interpretations, and statistical evaluation of the results of theradiological environmental surveillance activities for the reportperiod, including a comparison with operational controls, preoperationalstudies (as appropriate), and previous environmental surveillancereports and an assessment of the observed impacts of the stationoperation on the environment.In the event that some results are not available the report shall besubmitted noting the explaining the reasons for the missing results.The missing data shall be submitted as soon as possible in a supple-mentary repor The reports shall also include the following: a summary descriptionof the radiological environmental monitoring program including samplingmethods for each sample type, size and physical characteristics of eachsample type, sample preparation methods, analytical methods, and measuringequipment used; a map of all sampling locations keyed to a table givingdistances and directions from one reactor; the results of land usecensuses; and the results of licensee participation in the EnvironmentalProtection Agency's Environmental Radioactivity Laboratory Intercom-parisons Studies (Crosscheck) Program.B. Nonroutine Radiological Environmental Operating Reports"If a confirmed3 measured radionuclide concentration in an environ-mental sampling medium averaged over any quarter sampling periodexceeds the reporting level given in Table 4, a written report shallbe submitted to the Director of the NRC Regional Office (with a copyto the Director, Office of Nuclear Reactor Regulation) within 30 daysfrom the end of the quarter. If it can be demonstrated that thelevel is not a result of plant effluents (i.e., by comparison withcontrol station or preoperational data) a report need not be submitted,but shall be discussed in the annual report. When more than one ofthe radionuclides in Table 4 are detected in the medium, the reportinglevel shall have been exceeded if:concentration (1 + concentration (2) 1reporting level (1) reporting level (2) + >If radionuclides other than those in Table 4 are detected and aredue from plant effluents, a reporting level is exceeded if thepotential annual dose to an individual is equal to or greater thanthe design objective doses of 10 CFR Part 50, Appendix I. Thisreport shall include an evaluation of any release conditions,environmental factors, or other aspects necessary to explain theanomalous result.A confirmatory reanalysis of the original, a duplicate, or a new samplemay be desirable, as appropriate. The results of the confirmatoryanalysis shall be completed at the earliest time consistent with theanalysis, but in any case within 30 day TABLE 1OPERATIONAL RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAMExposure Pathway Number of Samplesa Sampling and aType and Frequencyand/or Sample and Locations Collection Frequency and AnalysisAIRBORNERadioiodine andParticulatesSamples from 3 offsite locations (indifferent sectors) of the highestcalculated annual average ground-level D/Q.Radioiodine Cannister:analyze weekly forI-1311 sample from the vicinity of acommunity having the highestcalculated annual average ground-level D/Q.Continuous sampleroperation with samplecollection weekly oras required by dustloading, whichever ismore frequentParticulate Sampler: (Gross beta radio-activity followingfilter change, composite(by location) for gammaisotopic quarterly1 sample from a control location15-30 km (10-20 miles) distant and din the least prevalent wind directionDIRECT RADIATIONf2 or more dosimeters or one in-strument for measuring and record-ing dose rate continuously to beplaced at each of the same loca-tions as for air particulates, andat each of three additional offsitelocations (different sectors) orhighest calculated annual averageground-level X/Q.Monthly or quarterlyGamma dose monthly orquarterly TABLE 1 (Continued)Exposure Pathwayand/or SampleNumber of Samplesaand LocationsSampling and aCollection FrequencyI_Type and Frequencyof AnalysisWATERBORNEGround1 sample upstream1 sample downstreamSamples from 1 or 2 sour es onlyif likely to be affected1 sample of each of 1 to 3 ofthe nearest water supplies whichcould be affected by itsdischargeComposite samplehoyerone-month period IQuarterlyComposite sample iover two-week periodif 1-131 anlysis isperformed, monthlycomposite otherwiseDrinkingGamma isotopic analysismonthly. Composite fortritium analysesquarterlyGamma isotopic andtritium analysisquarterlyI-131 analysis on eachcomposite when the dosecalculated for the con-sumption of the wateris greateE than 1 mremper year. Composite forGross P and gamma isotopicanalyses monthly. Compo-site for tritium analysisquarterly(1 sample from a control locationSediment fromShoreline1 sample from downstream areawith existing or potentialrecreational valueSemiannuallyGamma isotopic analyses .semiannuallyINGESTIONMilkSamples from milking animalsin 3 locations within 5 kmdistant having the highest dosepotential. If there are noneqthen, 1 sample from milkinganimals in each of 3 areasbetween 5 to 8 km distant wheredoses are calculated to begreater than 1 mrem per yearkSemimonthly when ani-mals are on pasture,monthly at other timesGamma isotopic and I-131analysis semimonthly whenanimals are on pasture;monthly at other times, TABLE 1 (Continued)Exposure Pathwayand/or SampleNumber of Samplesaand LocationsSampling and aCollection Frequency-Type and Frequencyof AnalysisMilk (cont'd)1-sample from milking animals ata control location (15-30 kmdistant and in the least prevalentwind direction)Fish andInvertebratesFood Products1 sample of each commercially andrecreationally important speciesin vicinity of discharge point1 sample of same species in areasnot influenced by plant discharge1 sample of each principal classof food products from any areawhich is irrigated by water inwhich liquid plant wastes havebeen dischargedSample in season, orsemianmtally. tf the.y. arenot seasonalAt time of harvest1Gamma isotopicanalysis on edibleportions (Gamma isotopicanalysis on edibleportion. I-131analysis on broadleaf vegetation3 samples of broad leaf vegetationgrown nearest offsite locationsof highest calculated annualaverage ground-level D/Q if milksampling is not performed1 sample of each of the similarvegetation grown 15-30 km distantin the least prevalent wind directionif milk sampling is not performedMonthly when availableMonthly when available(
TABLE I (Continued)aThe number, media, frequency and location of sampling may vary from site to site. It is recognized that, at times,it may not be possible or practical to obtain samples of the media of choice at the most desired location or time.In these instances suitable alternative media and locations may be chosen for the particular pathway in questionand submitted for acceptance. Actual locations (distance and direction) from the site shall be provided. Referto Regulatory Guide 4.1, "Programs for Monitoring Radioactivity in the Environs of Nuclear Power Plants."bParticulate sample filters should be analyzed for gross beta 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or more after sampling to allow for radon andthoron daughter decay. If gross beta activity in air or water is greater than ten times the mean of control samplesfor any medium, gamma isotopic analysis should-be performed on the individual samples.cGamma isotopic analysis means the identification and quantification of gamma-emitting radionuclides that may be (attributable to the effluents from the facility.dThe purpose of this sample is to obtain background information. If it is not practical to establish control loca-tions in accordance with the distance and wind direction criteria, other sites which provide valid background datamay be substituted.eCanisters for the collection of radioiodine in air are subject to channeling. These devices should be carefullychecked before operation in the field or several should be mounted in series to prevent loss of iodine.fRegulatory Guide 4.13 provides minimum acceptable performance criteria for thermoluminescence dosimetry (TLD)systems used for environmental monitoring. One or more instruments, such as a pressurized ion chamber, for measur-ing and recording dose rate continuously may be used in place of, or in addition to, integrating dosimeters. Forthe purposes of this table, a thermoluminescent dosimeter may be considered to be one chip, and two or more chipsin a packet may be considered as two or more dosimeters.gThe "upstream sample" should be taken at a distance beyond significant influence of the discharge. The "down-stream" sample should be taken in an area beyond but near the mixing zone. "Upstream" samples in an estuary mustbe taken far enough upstream to beyond the plant influence. QhGenerally, salt water is not sampled except when the receiving water is utilized for recreational activities.Composite samples should be collected with equipment (or equivalent) which is capable of collecting an aliquotat time intervals which are very short (e.g., hourly) relative to the compositing period (e.g., monthly).JGroundwater samples should be taken when this source is tapped for drinking or irrigation purposes in areas wherethe hydraulic gradient or recharge properties are suitable for contamination.kThe dose shall be calculated for the maximum organ and age group, using the methodology contained in RegulatoryGuide 1.109, Rev. I., and the actual parameters particular to the site.If harvest occurs more than once a year, sampling should be performed during each discrete harvest. If harvestoccurs continuously, sampling should be monthly. Attention should be paid to including samples of tuborous androot food product I .TABLE 1 (Continued)Note: In addition to the above guidance for operational monitoring, the following material is supplied for guid-ance on preoperational programs.Preoperational Environmental Surveillance ProgramA Preoperational Environmental Surveillance Program should be instituted two years prior to the institution of stationplant operation.The purposes of this program are:1. To measure background levels and their variations along the anticipated critical pathways in the areasurrounding the station.2. To train personnel3. To evaluate procedures, equipment and techniquesThe elements (sampling media and type of analysis) of both preoperational and operational programs should be essen-tially the same. The duration of the preoperational program, for specific media, presented in the following tableshould be followed:Duration of Preoperational Sampling Program for Specific Media6 months 1 year 2 years.airborne iodine .airborne particulates direct radiation (iodine in milk (while .milk (remaining analyses) .fish and invertebratesanimals are in pasture) .surface water .food products.groundwater .sediment from shorelinedrinking water TABLE 2Detection Capabilities for Environmental Sample AnalysisaLowerLimit of Detection (LLD)bAirborne ParticulateWater or Gas Fish Milk Food Products SedimentAnaysis (pCi/l) (pCi/M3) (pCi/kgwet) (pCWiM) (pCi/kg, wet) (pCi/kg, dry)gross beta3H54 Mn59Fe58,60Co65Zn95Zr-Nb131I134,137 Cs140 Ba-La2c1 x 10-2(3301530153010130260130260(0.5d15157 x 10 21 x 10 21300.8d151580150 TABLE 2NOTESAcceptable detection capabilities for thermoluminescent dosimeters used forenvironmental measurements are given in Regulatory Guide 4.13.bTable 2 indicates acceptable detection capabilities for radioactive materialsin environmental samples. These detection capabilities are tabulated interms of the lower limits of detection (LLDs). The LLD is defined, forpurposes of this guide, as the smallest concentration of radioactive materialin a sample that will yield a net count (above system background) that willbe detected with 95% probability with only 5% probability of falsely con-cluding that a blank observation represents a "real" signal.For a particular measurement system (which may include radiochemicalseparation):4.66 sbLLD = E
- V *2.22 * -* exp(-AMt)whereLLD is the lower limit of detection as defined above (as pCi perunit mass or volume)S is the standard deviation of the background counting rate or ofbthe counting rate of a blank sample as appropriate (as counts perminute)E is the counting efficiency (as counts per disintegration)V is the sample size (in units of mass or volume)2.22 is the number of disintegrations per minute per picocurieY is the fractional radiochemical yield (when applicable)A is the radioactive decay constant for the particular radionuclideAt is the elasped time between sample collection (or end of the samplecollection period) and time of countingThe value of S used in the calculation of the LLD for a particular measure-ment system should be based on the actual observed variance of the back-ground counting rate or of the counting rate of the blank samples (asappropriate) rather than on an unverified theoretically predicated variance.In calculating the LLD for a radionuclide determined by gamma-ray spectrometry,the background should include the typical contributions of other radionuclidesnormally present in the samples (e.g., potassium-40 in milk samples).Typical values of E, V, Y and At should be used in the calculatio It should be recognized that the LLD is defined as an a priori (beforethe fact) limit representing the capability of a measurement system andnot as a posteriori (after the fact) limit for a particular measurement.*GLLD for drinking water.dLLDs for 131I in water, milk and other food products correspond to one-quarter of the Appendix I (10 CFR Part 50) design objective dose-equivalentof 15 mrem/year for atmospheric releases and 10 mrem/yr for liquid releases tothe most sensitive organ and age group using the asssumptions given inRegulatory Guide 1.109, Rev. 1.eLLD for leafy vegetables.-K-For a more complete discussion of the LLD, and other detection limits, seethe following:(1) HASL Procedures Manual, HASL-300 (revised annually).(2) Currie, L. A., "Limits for Qualitative Detection and QuantitativeDetermination -Application to Radiochemistry" Anal. Chem. 40,586-93 (1968).(3) Hartwell, J. K., "Detection Limits for Radioisotopic CountingTechniques," Atlantic Richfield Hanford Company Report ARH-2537(June 22, 1972).
ITABLE 3Name ofLocation ofENVIRONMENTAL RADIOLOGICAL MONITORING PROGRAM ANNUAL SUMMARYFacility _ Docket No.Facility (County,_State) _Reporting Period(County, State)NIImhPr 0?Medium orPathway Sampled(Unit ofMeasurement)Type andTotal Numberof AnalysesPerformedLower LimitofDetectiona(LLD)All IndicatorLocationsMean (f)RangebLocation with HighestAnnual Mean bName Mean (f)Distance & RangeDirectionControl locationsMean (f)RangeNumber ofNonroutineReportedMeasurementsAir Particu-3lates (pCi/m )Gross P 4160.010.08(200/312)(0.05-2.0)Middletown5 miles 34000.10 (5/52)(0.08-2.0)0/08 (8/104)(0.05-1.40)1y-Spec. 32137cs0.010.05 (4/24)(0.03-0.13)Smithville 0.08 (2/4)2.5 miles 1600 (0.03-2.0)<LLD4131I0.070.03 (2/24)(0.01-0.08)Podunk 0.05 (2/4)4.0 miles 2700 (0.01-0.08)0.02 (2/4)1Fish pCi/kg(wet weight)y-Spec. 8130130<LLD<LLD90 (1/4)<LLD0<LLD<LLD0(60Co130120 (3/4)(90-200)River Mile 35 See Column 4<LLD0aSee Table 3, note b.bMean and range based upon detectable measurements only.is indicated in parentheses. (f)Fraction of detectable measurements at specified locationsCNote: The example data are provided for illustrative purposes onl TABLE 4REPORTING LEVELS FOR NONROUTINE OPERATING REPORTSReporting Level (RL)Broad LeafWater Airborne Particulate Fish Milk VegetationAnalysis (pCi/l) or Gases (pCi/m3) (pCi/Kg,wet) (pCi/l) (pCi/Kg, wet)H-3 3 x 104Mn-54 1 x 103 3 x 104Fe-59 4 x 102 1 x 104Co-58 1 x 103 3 x 104Co-60 3 x 102 1 x 104Zn-65 3 x 102 2 x 104Zr-Nb-95 4 x 102I-131 2 0.9 3 1 x 102 (Cs-134 30 10 1 x 103 60 1 x 103Cs-137 50 20 2 x 103 70 2 x 103Ba-La-140 2 x 1023 x 102A Figure 1I(This figure shall be of a suitable scale to show the distance anddirection of each monitoring station. A key shall be provided to indicatewhat is sampled at each location.)
Yankee Atomic Electric Companycc: Mr. Donald G. Allen, PresidentYankee Atomic Electric Company20 Turnpike RoadWestboro, Massachuset5,s 01581Greenfield Community College1 College DriveGreenfield, Massachusetts 01301