Exel(5n. Nuclear Plant Effluent and Radiological Environmental Monitoring Programs

Transcription

1 Exel(5n. Plant Effluent and Radiological Environmental Monitoring Programs

2 Exehtn. Two Programs,/ Radioactive Effluents Program o Measures releases of radioactivity from the station and calculates dose to the public,/ Radiological Environmental Monitoring Program (REMP) o Monitors the environment to measure station's impact and validates effluent monitoring,/ The purpose of both programs is to protect the health and safety of the public '/ Both are required by federal law and regulated by the NRC

3 Exel(bn. Radioactive Effluents Program '/ Established to identify and quantify principle radionuclides in station eff luents Consists of the evaluation of three primary exposure paths. Gaseous effluents o Liquid effluents o Direct radiation Effluents are treated prior to release to maintain public dose As Low As Reasonably Achievable (ALARA),/ Public dose is calculated per NRC guidance '/ Results are reported every year to the NRC in the station's Annual Radioactive Effluent Release Report, which becomes a public record.

4 Pathways Exehrn. 4. Direct Radiation (Sril DepositionJ 3. Birect Radiation {StationJ 2. Air lnhalation 1. Shrrreline Direct Radiation (Fishins, Picnrcins) Ï tepnsition

5 Exehbn. Gaseous Effluent Monitoring,/,/ Radioactive effluent stack monitoring consists of a side-stream sampler that continuously draws a sample from the stack Sample passes through a particulate filter, an iodine cartridge, and then a noble gas monitor o Particulate and iodine media are changed weekly and analyzed. Noble Gas concentrations are continuously monitored, with grab sampling and analysis performed weekly. Multiple detectors allow a wide operating range (from normal, low range to design-basis accident range) Tritium sampling and analysis is performed at a set frequency Dresden uses Separate Particulate, lodine, and Noble Gas (SPING) monitors on lhe 213 Chimney and 213 Reactor Building Ventilation Stack

6 Exekln,, N Effluent Monitor: Reactor BIdg Vent uclear

7 Exelt}n. Liquid Eftluent Monitoring,/ Liquid radwaste discharges are usually performed as a batch release, where the processed water to be discharged is quarantined in a tank that is sampled prior to discharge to ensure requirements are met During the discharge, effluents are continuously monitored with a side-stream sampler for gamma radiation The release is terminated at the first indication of a potential issue (monitor alarms or becomes unavailable, discharge rate is in question, etc.) o Dresden has not made a batch liquid radwaste discharge since Station cooling water system effluents are also continuously monitored by an side-stream sampler, with grab sampling and analysis performed routinely o.,/

8 ExelrSnNucìear Process Radiation Monitor: Service WateÈ ;"' I,-t I,,iii\ li

9 Exehln. Direct Radiation '/ Boiling Water Reactors (BWRs) have radioactive steam going through their turbines o The sides of the turbines are heavily shielded, but for maintenance access, the tops are not heavily shielded. Gammas from the decay of short-lived 16N are scattered back to ground,/./ level by aerial dispersion, resulting in "skyshine" dose Skyshine is not a significant source of public dose at PWRs Other contained sources of activity (e.9., radioactive storage facilities) are also evaluated for contribution to public dose Skyshine is the most significant source of calculated public dose at Dresden (-4 mrem (-0.04 msv) per year per operating unit) o REMP monitoring of direct radiation shows this is a conservative calculation

10 Exeldrn. Galculation of Public Dose Dose to the public is calculated per NRC guidance Regulatory Guide 1.109, Calculation of Annual Doses to Man from Routine Releases of Reactor Effluents for the Purpose of Evaluating Compliance with 1OCFR Part 50, Appendix I Regulatory Guide 1.111, Methods for Estimating Atmospheric Transport and Dispersion of Gaseous Effluents in Routine Releases from Light-Water-Cooled Reactors Regulatory Guide 1.113, Estimating Aquatic Dispersion of Effluents from Accidental and Routine Reactor Releases for the Purpose of lmplementing Appendix I NUREG-0133, Preparation of Radiological Effluent Technical Specifications for Power Plants Only "significant pathways" are evaluated. o. o

11 Exel{rn. Calculation of Public Dose (continued),/ Gaseous effluents o Noble gases contribute to total body and skin dose from exposure to or immersion in the plume. Particulates, iodines, tritium, and carbon-14 contribute to total body, skin, and organ dose from: lnhalation of activity in the air Exposure to activity deposited on the ground lngestion of vegetables containing deposited activity lngestion of milk and meat from forage animals that have ingested deposited activity

12 Exel(rn. Calculation of Public Dose (continued),/ Liquid effluents contribute to total body and organ dose from: o Drinking potable water containing activity o o o lngestion of activity in aquatic food (fish or shellfish), lngestion of vegetation irrigated with water containing activity lngestion of milk or meat from animals drinking activity in water or eating activity deposited by irrigation Direct exposure to activity in water during activities such as swimming or boating Direct exposure to activity deposited on the shoreline Public dose and public dose projections are calculated monthly and compared to regulations and station limits.

13 Exel{rn. Nucìear Radiological Environmental Monitoring Program (REMP) The REMP provides representative measurements of radiation and radioactive material in the environment. o o Provides verification that the station is not causing a significant adverse radiological impact to the environment Measurable effects from the station on the environment are within expectations derived from effluent measurements. Monitoring is conducted per NRC guidance contained in NUREG-1301 (for PWRs) and NUREG-1302 (for BWRs) Almost all samples are collected from off-site locations. Samples are routinely split with state agencies All REMP results are reported to the NRC in the Annual Radiological Environmental Operating Report, which becomes a public record.

14 Exel{rn. Air Monitoring One control location (upwind and distant from the station) and several indicator locations (normally in downwind sectors) Air particulate and iodine samplers continually collect samples. Samples are collected weekly. Particulate filters Analyzed weekly for gross beta Analyzed quarterly for gamma emitters. Charcoal cartridges are analyzed weekly for l-131 Dresden has thifteen (soon to be fourteen) air samplers, including downwind sectors, local communities, on-site locations, and the control location 10 miles upwind

15 ExelrSn= Environmental Air Sampler

16 Exel(gn. Air Sampler filter and lodine cartridge

17 Exel(ln. Direct Radiation Locations for monitoring generally consist of rings:. One location in each sector in the general area of the site boundary (inner ring). One location in each sector -6-8 km from the site (outer ring). One distant control location. Special lnterest locations such as nearby population centers, schools, etc Monitoring performed with Thermoluminescent Dosimeters (TLDs) that are collected and read quarterly The lllinois Emergency Management Agency maintains a Reuter- Stokes detector in each sector for continuous monitoring that is remotely accessible Dresden has inner and outer ring locations, as well as locations at all of the air samplers

18 Exel{rn. Environmental Radiation Dose Monitoring (TLD)

19 Exekln. Off-Site Water Monitoring,/ Surface Water (River) o One control location (upstream) and one indicator location (downstream) Samples are collected hourly with a compositor (preferred) or by routine grab samples Samples composited monthly for analysis for gamma emitters and gross beta Monthly samples composited quarterly for tritium analysis o Dresden monitors two upstream locations (on the DesPlaines and Kankakee Rivers) and one downstream indicator (on the lllinois River)./ Ground Water One or two wells if likely to be affected by the station. Quarterly collection, analyzed for tritium and gamma emitters o Dresden conservatively monitors two local wells, although no wells in the area are likely to be affected by station operations

20 Exelün" Kankakee River (upstream) surface water sampler

21 Exel(5n. Off-Site Water Monitoring (continued),/ Drinking Water o One control location (upstream) and one to three indicator locations (downstream) Samples are collected hourly with a compositor Samples are composited bi-weekly or monthly depending on projected dose Bi-weekly composites analyzed for l-131 Monthly composites analyzed for gross beta and gamma emitters Samples composited quarterly for tritium analysis. Dresden does not have any downstream drinking water supplies drawn from the lllinois River within one hundred miles of the station Sediment o Sampled semi-annually and analyzed for gamma emitters. Dresden also monitors spoils of downstream dredging operations

22 Exelon. lngestion Pathway Monitoring M IK. One control location and three indicator locations Sampled bi-weekly when animals are on pasture Sampled monthly when animals are not on pasture Samples analyzed for l-131 and gamma emitters. Dresden does not have any milking cows within 5 miles Fish o One control location and one indicator location Sampled semi-annually or when in season Samples analyzed for gamma emitters o Dresden samples upstream on the DesPlaines River and downstream Vegetation. Sampled annually during harvest season o Samples analyzed for gamma emitters, including 1311

23 Exekbn. Dresden REMP results,/ Year after year, no activity is detected in the environment due to the operation of Dresden Station o Gross beta in air and water samples are consistent with control locations o Direct radiation monitoring results are consistent with the control location o Tritium downstream and in well water are consistent with upstream values o Trace sediment activity due to radioactive fallout from weapons testing. Naturally occurring radioactive material (78e, +0K, 228ffç,228Th, 232Th) is routinely detected in several media

24 Exekbn. Nucìear,/./,/ The Effluents Program and the REMP are in place to protect the health and safety of the public o Effluents Program focus is on measurement of releases from the station and resultant dose o REMP focus is on station impact on the environment and validates Effluent Program Both programs are controlled by federal regulation or guidance Regulatory oversight is provided by the NRC All results are reported annually to the NRC and become part of the public record,/ Questions?