NRC Generic Letter 1978-10
| ML031280377 | |
| Person / Time | |
|---|---|
| Issue date: | 04/11/1978 |
| From: | Goller K Office of Nuclear Reactor Regulation |
| To: | |
| References | |
| GL-78-010 | |
| Download: ML031280377 (18) | |
49REG
Do°C M 7ET
UNITED STATES
so A iNUCLEAR REGULATORY COMMISSION
WASHINGTON, D. C. 20555 - -
April 11, 1978 CgL- 22-4O
To All Power Reactor Licensees Gentlemen:
Enclosed for your information and possible future use is the current NRC
guidance on radiological environmental monitoring for nuclear power plants.
10 CFR Parts 20 and 50 require that radiological environmental monitoring programs be established to provide data on measurable levels of radiation and radioactive materials in the site environs. In addition, Appendix I
to 10 CFR Part 50 requires that the relationship between quantities of radioactive material released in effluents during normal operation, includ- ing anticipated operational occurrences, and resultant radiation doses to individuals from principal pathways of exposure be evaluated.
Regulatory Guide 4.8, Environmental Technical Specifications for Nuclear Power Plants, was issued for comment in December 1975. The enclosed tech- nical position on the radiological portion of environmental monitoring was formulated by an NRC working group which considered the comments received on Regulatory Guide 4.8. This position sets forth guidance for developing an acceptable minimum radiological monitoring program to meet the regula- tory requirements of 10 CFR Parts 20 and 50. Local site characteristics need to be examined to determine if pathways not covered by this guide may significantly contribute to an individual's dose and shouldbe included in the sampling program. The acceptability of changes to radiological environ- mental monitoring programs at operating reactors will be evaluated based on this guidance as well as on a review of past operating data.
We are developing technical specifications which incorporate the Appendix I
guidance set forth in the enclosed position. These specifications will be implemented on all operating reactors in the future. This position is be- ing provided to you at the present time for information only and no action is required on your part. More specific guidance on technical specifications relating to the implementation of Appendix I to 10 CFR 50 will be provided to you in the future.
Karl R. Goller, Assistant Director for Operating Reactors Division of Operating Reactors Office of Nuclear Reactor Regulation
March 1978 . .
Branch Technical Position Background Regulatory Guide 4.8, Environmental Technical Specifications for Nuclear Power Plants, issued for comment in December 1975, is being revised based on comments received. The Radiological Assessment Branch has developed the following Branch Position on the radiological portion of the environ- mental monitoring program. The position was formulated by an NRC working group which considered comments received after the issuance of the Regulatory Guide 4.8.
10 CFR Parts 20 and 50 require that radiological environmental monitoring programs be established to provide data on measurable levels of radiation and radioactive materials in the site environs. In addition, Appendix I to
10 CFR Part 50 requires that the relationship between quantities of radio- active material released in effluents during normal operation, including anticipated 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 measures used for controlling the release of radioactive materials. Surveillance should be established to identify changes in the use of unrestricted areas (e.g., for agricultural purposes) to provide a basis for modifications in the monitoring programs for evaluating doses to individuals from principal pathways of exposure. NRC Regulatory Guide 4.1, Rev. 1, "Programs for Monitoring Radioactivity in the Environs of Nuclear Power Plants," provides an 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 radiological monitoring program.. Local site characteristics must be examined to determine if pathways not covered by this guide may significantly contribute to an individual's dose and should be included in the sampling program.
AN ACCEPTABLE RADIOLOGICAL
ENVIRONMENTAL MONITORING PROGRAM
Program Requirements Environmental samples shall be to3lected and analyzed according to Table 1 at locations shown in Figure 1.I1 Analytical techniques used shall be such that the detection capabilities in Table 2 are achieved.
The results of the radiological environmental monitoring are intended to supplement the results of the radiological effluent monitoring by verifying that the measurable concentrations of radioactive materials and levels of radiation are not higher than expected on the basis of the effluent measure- ments and modeling of the environmental exposure pathways. Thus, the specified environmental monitoring program provides measurements of radiation and 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 of commercial operation (or other period corresponding to a maximum burnup in the initial core cycle). Following this period, program changes may be proposed based on operational experience.
The specified detection capabilities are state-of-the-art for routine environmental measurements in industrial laboratories. The LLDs for I-131 in water, milk and other food products correspond to one-quarter of the Appendix I (10 CFR Part 50) design objective dose-equivalent of 15 mrem/yr for atmospheric releases and 10 mrem/yr for liquid releases to the most sensitive organ and age group. They are based on the assumptions given in Regulatory Guide 1.109, Rev 1.
Deviations are permitted from the required sampling schedule if specimens are 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 the end of the next sampling period. All deviations from the sampling schedule shall be documented in the annual report.
The laboratories of the licensee and licensee's contractors which perform analyses 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 the l
It may be necessary to require special studies on a case-by-case and site specific basis to establish the relationship between quantities of radioactive material released in effluents, the concentrations in environmental media, and the resultant doses for important pathways.
determinations (sample medium-radionuclide combination) that are offered by EPA and that also are included in the monitoring program. The results of analysis of these crosscheck samples shall be included in the annual report.
If the results of a determination in the EPA crosscheck program (or equivalent program) are outside the specified control limits, the laboratory shall investigate the cause of the problem and take steps to correct it. The results of this investigation and corrective action shall be included in the annual report.
The requirement for the participation in the EPA crosscheck program, or similar program, is based on the need for independent checks on the precision and accuracy of the measurements of radioactive material in environmental sample matrices as part of the quality assurance program for environmental monitoring in order to demonstrate that the results are reasonably valid.
A census shall be conducted annually during the growing season to determine the location of the nearest milk animal and nearest garden greater than
50 sq. meters (500 sq. ft.) producing broad leaf vegetation in each of
2 For the 16 meteorological sectors within a distance of 8 km (5 miles).
elevated releases as defined in Regulatory Guide 1.111, Rev. 1., the census shall also identify the locations of all milk animals, and gardens greater than 50 sq. meters producing broad leaf vegetation out to a distance 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 those previously sampled, or if the census results in changes in the location used in 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 days identifying the new location (distance and direction). Milk animal or garden locations resulting in higher calculated doses shall be added to the surveillance program as soon as practicable.
The sampling location having the lowest calculated dose may then be dropped from the surveillance program at the end of the grazing or growing season during which the census was conducted. Any location from which milk can no longer be obtained may be dropped from the surveillance program after z
Broad leaf vegetation sampling may be performed at the site boundary in a sector with the highest D/Q in lieu of the garden census.
notifying the NRC in writing that they are no longer obtainable at that location. The results of the land-use census shall be reported in the annual report.
The census of milk animals and gardens producing broad leaf vegetation is based on the requirement in Appendix I of 10 CFR Part 50 to "Identify changes in the use of unrestricted areas (e.g., for agricultural purposes)
to permit modifications in monitoring programs for evaluating doses to individuals from principal pathways of exposure." The consumption of milk from 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 radioiodine in the environment than vegetation. If the census reveals milk animals are not 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 of
2 kg/M 2, will produce the 26 kg/yr assumed in Regulatory Guide 1.109, Rev 1., for child consumption of leafy vegetation. The option to consider the garden to be broad leaf vegetation at the site boundary in a sector with the highest D/Q should be conservative and that location may be used to calculate doses due to radioactive effluent releases in place of the actual locations which would be determined by the census. This option does not apply to plants with elevated releases as defined in Regulatory Guide 1.111, Rev. 1.
Reporting Requirement A. Annual Environmental Operating Report, Part B, Radiological.
A report on the radiological environmental surveillance program for the previous calendar year shall be submitted to the Director of the NRC Regional Office (with a copy to the Director, Office of Nuclear Reactor Regulation) as a separate document by May 1 of each year.
The period of the first report shall begin with the date of initial criticality. The reports shall include a summary (format of Table 3),
interpretations, and statistical evaluation of the results of the radiological environmental surveillance activities for the report period, including a comparison with operational controls, preoperational studies (as appropriate), and previous environmental surveillance reports and an assessment of the observed impacts of the station operation on the environment.
In the event that some results are not available the report shall be submitted noting the explaining the reasons for the missing results.
The missing data shall be submitted as soon as possible in a supple- mentary report.
The reports shall also include the following: a summary description of the radiological environmental monitoring program including sampling methods for each sample type, size and physical characteristics of each sample type, sample preparation methods, analytical methods, and measuring equipment used; a map of all sampling locations keyed to a table giving distances and directions from one reactor; the results of land use censuses; and the results of licensee participation in the Environmental Protection 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 period exceeds the reporting level given in Table 4, a written report shall be submitted to the Director of the NRC Regional Office (with a copy to the Director, Office of Nuclear Reactor Regulation) within 30 days from the end of the quarter. If it can be demonstrated that the level is not a result of plant effluents (i.e., by comparison with control station or preoperational data) a report need not be submitted, but shall be discussed in the annual report. When more than one of the radionuclides in Table 4 are detected in the medium, the reporting level shall have been exceeded if:
concentration (1 + concentration (2) 1 reporting level (1) reporting level (2) + >
If radionuclides other than those in Table 4 are detected and are due from plant effluents, a reporting level is exceeded if the potential annual dose to an individual is equal to or greater than the design objective doses of 10 CFR Part 50, Appendix I. This report shall include an evaluation of any release conditions, environmental factors, or other aspects necessary to explain the anomalous result.
A confirmatory reanalysis of the original, a duplicate, or a new sample may be desirable, as appropriate. The results of the confirmatory analysis shall be completed at the earliest time consistent with the analysis, but in any case within 30 days.
TABLE 1 OPERATIONAL RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM
Exposure Pathway Number of Samplesa Sampling and aType and Frequency and/or Sample and Locations Collection Frequency and Analysis AIRBORNE
Samples from 3 offsite locations (in Radioiodine Cannister:
Radioiodine and different sectors) of the highest analyze weekly for Particulates calculated annual average ground- I-131 level D/Q.
1 sample from the vicinity of a Continuous sampler Particulate Sampler: (
community having the highest operation with sample Gross beta radio- calculated annual average ground- collection weekly or activity following level D/Q. as required by dust filter change, composite loading, whichever is (by location) for gamma more frequent isotopic quarterly
1 sample from a control location
15-30 km (10-20 miles) distant and d in the least prevalent wind direction DIRECT RADIATIONf 2 or more dosimeters or one in- Monthly or quarterly Gamma dose monthly or strument for measuring and record- quarterly ing dose rate continuously to be placed at each of the same loca- tions as for air particulates, and at each of three additional offsite locations (different sectors) or highest calculated annual average ground-level X/Q.
TABLE 1 (Continued)
I_
Exposure Pathway Number of Samplesa Sampling and a Type and Frequency and/or Sample and Locations Collection Frequency of Analysis WATERBORNE
1 sample upstream Composite samplehoyer Gamma isotopic analysis
1 sample downstream one-month period I monthly. Composite for tritium analyses quarterly Ground Samples from 1 or 2 sour es only Quarterly Gamma isotopic and (
if likely to be affected tritium analysis quarterly Drinking 1 sample of each of 1 to 3 of Composite sample i I-131 analysis on each the nearest water supplies which over two-week period composite when the dose could be affected by its if 1-131 anlysis is calculated for the con- discharge performed, monthly sumption of the water composite otherwise is greateE than 1 mrem per year. Composite for Gross P and gamma isotopic analyses monthly. Compo- site for tritium analysis quarterly
1 sample from a control location Sediment from 1 sample from downstream area Semiannually Gamma isotopic analyses .
Shoreline with existing or potential semiannually recreational value INGESTION
Milk Samples from milking animals Semimonthly when ani- Gamma isotopic and I-131 in 3 locations within 5 km mals are on pasture, analysis semimonthly when distant having the highest dose monthly at other times animals are on pasture;
potential. If there are noneq monthly at other times, then, 1 sample from milking animals in each of 3 areas between 5 to 8 km distant where doses are calculated to be greater than 1 mrem per yeark
TABLE 1 (Continued)
Number of Samplesa Sampling and a Type and Frequency Exposure Pathway of Analysis and/or Sample and Locations Collection Frequency
-
Milk (cont'd) 1-sample from milking animals at a control location (15-30 km distant and in the least prevalent wind direction)
Fish and 1 sample of each commercially and Sample in season, or Gamma isotopic recreationally important species semianmtally. tf the.y. are analysis on edible Invertebrates in vicinity of discharge point not seasonal portions (
1 sample of same species in areas not influenced by plant discharge Food Products 1 sample of each principal class At time of harvest1 Gamma isotopic of food products from any area analysis on edible which is irrigated by water in portion. I-131 which liquid plant wastes have analysis on broad been discharged leaf vegetation
3 samples of broad leaf vegetation Monthly when available grown nearest offsite locations of highest calculated annual average ground-level D/Q if milk sampling is not performed
1 sample of each of the similar vegetation grown 15-30 km distant Monthly when available
(
in the least prevalent wind direction if milk sampling is not performed
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 question and submitted for acceptance. Actual locations (distance and direction) from the site shall be provided. Refer to 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 and thoron daughter decay. If gross beta activity in air or water is greater than ten times the mean of control samples for 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 data may be substituted.
eCanisters for the collection of radioiodine in air are subject to channeling. These devices should be carefully checked 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. For the purposes of this table, a thermoluminescent dosimeter may be considered to be one chip, and two or more chips in 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 must be taken far enough upstream to beyond the plant influence. Q
hGenerally, 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 aliquot at 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 where the 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 Regulatory Guide 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 harvest occurs continuously, sampling should be monthly. Attention should be paid to including samples of tuborous and root food products.
I .
TABLE 1 (Continued)
for guid- Note: In addition to the above guidance for operational monitoring, the following material is supplied ance on preoperational programs.
Preoperational Environmental Surveillance Program institution of station A Preoperational Environmental Surveillance Program should be instituted two years prior to the plant operation.
The purposes of this program are:
the area
1. To measure background levels and their variations along the anticipated critical pathways in surrounding the station.
2. To train personnel
3. To evaluate procedures, equipment and techniques should be essen- The elements (sampling media and type of analysis) of both preoperational and operational programs the following table tially the same. The duration of the preoperational program, for specific media, presented in should be followed:
Duration of Preoperational Sampling Program for Specific Media
6 months 1 year 2 years
. airborne iodine . airborne particulates direct radiation (
iodine in milk (while . milk (remaining analyses) . fish and invertebrates animals are in pasture) . surface water . food products
. groundwater . sediment from shoreline drinking water
TABLE 2 Detection Capabilities for Environmental Sample Analysisa Lower Limit of Detection (LLD)b Airborne Particulate Water or Gas Fish Milk Food Products Sediment Anaysis (pCi/l) (pCi/M 3) (pCi/kgwet) (pCWiM) (pCi/kg, wet) (pCi/kg, dry)
gross beta 2c 1 x 10-2 (
3H
330
54Mn 15 130
59Fe 30 260
58 60
, Co
15 130
6 5 Zn
30 260
9 5 Zr-Nb
10
131I
(
0.5d 7 x 10 2 0.8d
134,137 Cs
15 1 x 10 2 130 15 80 150
140 Ba-La 15 15
TABLE 2 NOTES
Acceptable detection capabilities for thermoluminescent dosimeters used for environmental measurements are given in Regulatory Guide 4.13.
bTable 2 indicates acceptable detection capabilities for radioactive materials in environmental samples. These detection capabilities are tabulated in terms of the lower limits of detection (LLDs). The LLD is defined, for purposes of this guide, as the smallest concentration of radioactive material in a sample that will yield a net count (above system background) that will be 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 radiochemical separation):
4.66 sb LLD = E * V *2.22 *- * exp(-AMt)
where LLD is the lower limit of detection as defined above (as pCi per unit mass or volume)
S is the standard deviation of the background counting rate or of bthe counting rate of a blank sample as appropriate (as counts per minute)
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 picocurie Y is the fractional radiochemical yield (when applicable)
A is the radioactive decay constant for the particular radionuclide At is the elasped time between sample collection (or end of the sample collection period) and time of counting The 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 (as appropriate) 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 radionuclides normally present in the samples (e.g., potassium-40 in milk samples).
Typical values of E, V, Y and At should be used in the calculation.
It should be recognized that the LLD is defined as an a priori (before the fact) limit representing the capability of a measurement system and not 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-equivalent of 15 mrem/year for atmospheric releases and 10 mrem/yr for liquid releases to the most sensitive organ and age group using the asssumptions given in Regulatory Guide 1.109, Rev. 1.
eLLD for leafy vegetables.
-K-For a more complete discussion of the LLD, and other detection limits, see the following:
(1) HASL Procedures Manual, HASL-300 (revised annually).
(2) Currie, L. A., "Limits for Qualitative Detection and Quantitative Determination - Application to Radiochemistry" Anal. Chem. 40,
586-93 (1968).
(3) Hartwell, J. K., "Detection Limits for Radioisotopic Counting Techniques," Atlantic Richfield Hanford Company Report ARH-2537 (June 22, 1972).
I
TABLE 3 ENVIRONMENTAL RADIOLOGICAL MONITORING PROGRAM ANNUAL SUMMARY
Name of Facility _ Docket No.
Location of Facility (County,_State) _Reporting Period (County, State)
NIImhPr 0?
Type and Lower Limit All Indicator bLocation with Highest Control locations Number of Medium or Nonroutine Pathway Sampled Total Number of Locations Annual Mean b Mean (f)
of Analyses Detectiona Mean (f) Name Mean (f) Range Reported (Unit of Measurements Measurement) Performed (LLD) Range Distance & Range Direction Air Particu- 3 1 lates (pCi/m ) Gross P 416 0.01 0.08(200/312) Middletown 0.10 (5/52) 0/08 (8/104)
(0.05-2.0) 5 miles 3400 (0.08-2.0) (0.05-1.40)
y-Spec. 32
0.01 0.05 (4/24) Smithville 0.08 (2/4) <LLD 4
137cs
(0.03-0.13) 2.5 miles 1600 (0.03-2.0)
131I 0.07 0.03 (2/24) Podunk 0.05 (2/4) 0.02 (2/4) 1
(0.01-0.08) 4.0 miles 2700 (0.01-0.08)
Fish pCi/kg (wet weight) y-Spec. 8
130 <LLD <LLD 90 (1/4) 0
130 <LLD <LLD <LLD 0
<LLD 0
(
6 0 Co 130 120 (3/4) River Mile 35 See Column 4
(90-200)
aSee Table 3, note b.
bMean and range based upon detectable measurements only. Fraction of detectable measurements at specified locations is indicated in parentheses. (f)
CNote: The example data are provided for illustrative purposes only.
TABLE 4 REPORTING LEVELS FOR NONROUTINE OPERATING REPORTS
Reporting Level (RL)
Broad Leaf Water Airborne Particulate Fish Milk Vegetation Analysis (pCi/l) or Gases (pCi/m 3) (pCi/Kg,wet) (pCi/l) (pCi/Kg, wet)
H-3 3 x 104 Mn-54 1 x 103 3 x 104 Fe-59 4 x 102 1 x 104 Co-58 1 x 103 3 x 104 Co-60 3 x 102 1 x 104 Zn-65 3 x 102 2 x 104 Zr-Nb-95 4 x 102 I-131 2 0.9 3 1 x 102 (
Cs-134 30 10 1 x 103 60 1 x 103 Cs-137 50 20 2 x 103 70 2 x 103 Ba-La-140 2 x 102 3 x 102 A
Figure 1I
distance and (This figure shall be of a suitable scale to show the provided to indicate direction of each monitoring station. A key shall be what is sampled at each location.)
Yankee Atomic Electric Company cc: Mr. Donald G. Allen, President Yankee Atomic Electric Company
20 Turnpike Road Westboro, Massachuset5,s 01581 Greenfield Community College
1 College Drive Greenfield, Massachusetts 01301