ML22227A074

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Overview of Pilgrim Liquid Discharge Considerations NOAA
ML22227A074
Person / Time
Site: Pilgrim
Issue date: 08/10/2022
From: Sturzebecher K
Reactor Decommissioning Branch
To:
Sturzebecher K, 301-415-8534
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ML22227A073 List:
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Download: ML22227A074 (35)
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Text

Overview of Pilgrim Liquid Discharge Considerations Briefing for NOAA (with U.S. EPA)

U.S. NRC 10 AUG 2022

Contents

1. Review of Regulatory Approach to Effluents
2. Water Schema for a Boiling Water Reactor (BWR)
3. A Brief History of Effluent Releases at Pilgrim
4. Routine Environmental Monitoring Near Pilgrim 2
1. The Regulatory Approach for Radionuclides
  • 40 CFR 190 (U.S. EPA)

Regulations - NRC

  • Radiation safety regulations apply to all licensees (medical, manufacturing, power, etc)
  • Objectives Based
  • Performance Objectives vs Specific Criteria
  • What vs How
  • NRC compared to OSHA
  • Radiation Dose Based
  • Absorbed dose is the best indicator of potential human health risks
  • Humans are the most sensitive population
  • Regulatory limits are not safety limits (10 CFR 20)
  • Conservative assumptions in guidance documents 4

NRC - 10 CFR 20 5

NRC - 10 CFR 20 6

NRC - 10 CFR 20 Another Option Available 7

Regulations - EPA (40 CFR 190) 8

EPA - 40 CFR 190 H-3 (Tritium) not listed 9

Regulations - Existing NPDES Permit 10

2. Water Schema for a BWR 11

12

Comparisons of Basic Indicators of Water Quality Parameter Torus*

Dryer Separator Pit /

Reactor Cavity*

Spent Fuel Pool*

Treated Water Tank Plymouth Town Water pH 7.61 6.72 7.22 8.89 Conductivity

(µS/cm) 352 17.0 39.2 1

239 Boron (ppb) 162 22.7 20.4 10 20.4 Chloride (ppb) 89,600 1,680 4,270 10 220,000 TOC (ppb) 273 101 96.2 200 1,091 Nitrate (ppb) 30 (post UV) 2,210 Sulfate (ppb) 10 (post UV) 7,700

  • Not representative of post-treatment expectations 13

14

3. History of Effluent Releases Publicly available at: https://www.nrc.gov/reactors/operating/ops-experience/tritium/plant-info.html 15

0 1

3 0

4 6

29 5

21 1

7 2

2 0

0 0

0 50000 100000 150000 200000 250000 300000 350000 0

5 10 15 20 25 30 35 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 Number of liquid releases Year Number of Liquid Releases & Volume - Pilgrim Station Volume (gallons)

Number of Releases 16

0 0.141 0.23 0

1.98 2.48 4.43 0.099 6.2 0.0039 3.56 0.0015 0.00082 0

0 0

0 50 100 150 200 250 300 350 400 450 500 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 Tritium Activity Released (Curies)

Year Comparison of Annual Tritium Releases, Gas & Liquid - Pilgrim Liquid Releases Gas Releases Note: values in the blue call-outs show the activity of Tritium in the liquid release, in Curies 17

3.00 0.90 0.57 0.10 0.05 0.12 0.08 0.03 0.03 0.05 0.02 0.02 0.02 0.05 0.01 0.00 0

20 40 60 80 100 120 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 Dose from ALL Radionuclides in millirem Year Comparison of Liquid and Gas Releases to Limits - Pilgrim Liquid Releases Gas Releases Note: values in the blue call-outs show the TOTAL whole-body dose for ALL radionuclides and ALL releases in that year NRC annual whole-body dose limit as found in 10 CFR 20.1301 EPA annual whole-body dose limit as found in 40 CFR 190 Typical whole-body dose from one transcontinential flight in the summer season (4 millirem) 18

4. Environmental Monitoring Publicly available at: https://www.nrc.gov/reactors/operating/ops-experience/tritium/plant-info.html 19

Radiological Environmental Monitoring Program

  • Required as part of the facilitys licensing basis
  • Results reported annually
  • Described in Regulatory Guide 04-001
  • Objectives
  • Evaluate the local environment to establish a baseline prior to operation
  • Determine if any measurable radiation or radioactive materials are attributable to plant operation
  • Determine if any measurable radiation or radioactive materials that are attributable to plant operation are commensurate with the reported effluents and meet design objectives 20

Samples and Monitoring 21

Sampling Results - Aquatic Edibles 2020

  • Shellfish:
  • Blue mussels and soft-shelled clams
  • Natural K-40 detected, as expected
  • No plant-related radionuclides, results similar to pre-operational period
  • Lobster:
  • Collected from outfall June, July, August, September
  • Results same as shellfish
  • Fish:
  • Some species harder to collect as warm discharge water has stopped
  • Results same a shellfish 22

Sample Results - Surface Water 2020 Release Point Note: No H-3 (tritium) was detected in 2011, the year with the largest number of liquid releases Sample Point 23

24

25

26

Supplementary Slides 27

Dose Calculations - Assumptions and Example Fish: 21 kg/yr Shellfish: 9 kg/yr Swimming: 52 hrs/yr Boating: 52 hrs/yr 28

Groundwater - 2020 Annual Report EPA Drinking Water Standard:

  • Assumes that all drinking water in a year contains tritium at this level
  • Is assumed to equal 4 mrem/yr (not correct and a significant over-estimate) 29

Tritium in Perspective

  • A radioactive isotope of Hydrogen (one proton, two neutrons)
  • Produced naturally in the upper atmosphere when cosmic rays interact with Nitrogen atoms (along with C-14 and Be-7)
  • Produced by reactors, however releases are at fractions of the natural background production rate [EPA fact sheet]
  • Can be found at very low concentrations in lakes and streams (about 4 pCi/L)
  • Radiation emitted as Beta particles of very low energy (cannot penetrate the skin surface)
  • Rapidly incorporates with water molecules and cannot be removed
  • Because water turns over rapidly in the body, tritium in the body is rapidly cleared from tissues [EPA fact sheet, 10-day biological half-life]

30

Relative Risks - Tritium

  • Dose per unit of radioactivity in the body - ingestion
  • K-40: 5.02 E-09
  • Cs-137: 1.35E-08
  • Co-60: 7.28 E-09
  • Ra-226: 6.83 E-06 [Bone Surface]
  • Th-232: 1.85 E-05 [Bone Surface]

https://www.epa.gov/radiation/federal-guidance-report-no-11-limiting-values-radionuclide-intake-and-air-concentration 31

32 0.1 18.6 50.0 26.9 25,271.0 68,450.0 0

10,000 20,000 30,000 40,000 50,000 60,000 70,000 80,000 H-3 K-40 Cs-137 Co-60 Ra-226 Th-232 Relative Risk (millirem per microCurie ingested)

Radionuclide Comparison of Tritium Risk to Other Radionuclides

Popular shopping site Tritium activity not even listed No warning or precautions Found online Each watch contains 27,000 microCuries of H-3 33

34

Radiopharmaceuticals in River Water 35 https://www.ncbi.nlm.nih.gov/books/NBK234160/

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