Under federal regulations, all nuclear power plants have stringent environmental monitoring programs to ensure there are no negative effects from plant operations. The U.S. Nuclear Regulatory Commission (USNRC) requires licensees to begin these programs at nuclear plant sites at least 2 years before the plant starts operating. Because radiation is naturally present in the environment, the preoperational monitoring is designed to establish a baseline the company later will use to ensure that the plant’s impact on the environment remains minimal. The USNRC requires nuclear plants to submit a report each year on the results of their monitoring programs.
The USNRC requires the operators of nuclear power plants to sample air at various locations in the vicinity of the plants to determine if releases are detectable in the environment off site. The environmental monitoring system is covered under the Radiological Environmental Monitoring Program (REMP): typically, measurements are made at five stations: three near the plant boundary in the direction of most likely wind transport; one in the vicinity of a community likely to have the greatest chance of exposure; and one at control location 15 to 30 km distant in the upwind direction of prevailing winds (NUREG 1301). Radioiodine is measured weekly and gross beta activity of particulates captured on filters is measured quarterly. Analyses to identify gamma-emitting radionuclides are done on composite samples weekly.
The results of a licensee’s effluent release program, which provides estimates of the public health impact of the releases, and radiological environmental monitoring program must be reported annually to the USNRC. Both reports are available to the public via the USNRC website. Historical
reports are available electronically in the USNRC system from about 2000 to the present. Prior to that, reports are available only in microfiche.
For a waterborne exposure pathway a sampling and analysis program shown in Table H.1 is recommended.
The Radiological Effluent Technical Specifications (RETS) require that the licensee submit:
- An annual radiological environmental monitoring report which is designed to assess the impact of radiological effluent releases into the environment; and
- A Special Report within 30 days of discovery of the event if predetermined levels of radioactivity are exceeded.
The USNRC also requires that the licensee participate in an Interlaboratory Comparison Program to ensure the accuracy and precision of the licensee’s data.
The REMP has allowed licensees significant flexibility to make changes to their programs without prior USNRC approval.1 The historical trend has been to reduce the scope of the program as a result of continued nondetection of radioactivity.
1 However, licensees must notify the USNRC of any changes, and the USNRC has regulatory recourse if the changes are not in accord with regulations.
TABLE H.1 Water Sampling and Analysis Recommendations
|Sample||Number of Representative Samples and Sample Locations||Sampling and Collection Frequency||Type and Frequency of Analysis|
|Surface water||One sample upstream (Wa1), one sample downstream (Wa2)||Composite sample over 1-month period||Gamma isotopic analysis monthly; composite for tritium analysis quarterly|
|Groundwater||Samples from one or two sources (Wb1, Wb2) only if likely to be affected||Quarterly||Gamma isotopic and tritium analysis quarterly|
|Drinking water||One sample of each of on to three (Wc1-Wc3) of the nearest water supplies that could be affected by its discharge; one sample from a control location (Wc4)||composite sample over 2-week period when I-131 analysis is performed; monthly composite otherwise||1-131 analysis on each composite when the dose calculated for the consumption of the water is greater than 1 mrem per year. Composite for gross beta and gamma
isotopic analyses monthly.
Composite for tritium analysis quarterly.
|Sediment from shoreline||One sample from downstream area with existing or potential recreational value (Wd1)||Semiannually||Gamma isotopic analysis semiannually|
a. Gamma isotopic analysis means the Identification and quantification of gamma-emitting radionuclides that may be attributable to the effluents from the facility.
b. The “upstream sample” shall be taken at a distance beyond significant influence of the discharge. The “downstream” sample shall be taken in an area beyond but near the mixing zone. “Upstream” samples in an estuary must be taken far enough upstream to be beyond the plant influence. Saltwater shall be sampled only when the receiving water is utilized for recreational activities.
c. A composite sample is one in which the quantity (aliquot) of liquid sampled is proportionalto the quantity of flowing liquid and in which the method of sampling employed results in a specimen that is representative of the liquid flow. In this program composite sample aliquots shall be collected at time intervals that are very short (e.g., hourly) relative to the compositing period (e.g., monthly) in order to ensure obtaining a representative sample.
d. Groundwater samples shall 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.
SOURCE: Offsite Dose Calculation Manual Guidance: Standard Radiological EffluentControls for PWRs, Generic Letter 89-01, Supplement No. 1, April 1991, U.S. NRC, NUREG-1301.
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