ML20352A211
| ML20352A211 | |
| Person / Time | |
|---|---|
| Issue date: | 12/17/2020 |
| From: | Stutzcage E NRC/NRR/DRA |
| To: | |
| Stutzcage E | |
| Shared Package | |
| ML20352A220 | List: |
| References | |
| Download: ML20352A211 (13) | |
Text
ALARA from a Regulatory Perspective January 5, 2021 Ed Stutzcage, Health Physicist Radiation Protection and Consequence Branch Division of Risk Assessment Office of Nuclear Reactor Regulation
Regulatory Framework
- Licensees shall use, to the extent practical, procedures and engineering controls to achieve occupational doses that are ALARA (10 CFR 20.1101)
- For occupational ALARA programs
- Compliance is judged on whether the licensee has incorporated measures to track and if necessary to reduce exposures not whether exposures represent absolute minimum (56 FR 23360, May 21, 1991)
- NRC oversight is performance-based and risk-informed
- What is Reasonably Achievable?
- Collective dose is factored into evaluation of occupational ALARA programs under the Reactor Oversight Process (ROP)
Slide 2 of 13
U.S. Commercial LWR Collective Dose 1974 - 2019 Average Collective Dose per Reactor 2019 Collective Dose (person-rem)
BWR: 32 PWR: 64 Average: 96 Slide 3 of 13
Average Measurable Dose per Worker 1974 - 2019 Average Measurable Dose per Individual*
2019 Average Measurable Dose (mrem)
BWR: 120 PWR: 70 Average: 90
- Not adjusted for transient workers.
Slide 4 of 13
Average Number of Workers with Measurable Dose 1974 - 2019 Average Number of Individuals with Measurable Dose per Reactor 2019 Avg. # of Individuals with Measurable Dose per Reactor BWR: 909 PWR: 383 Average: 419 Slide 5 of 13
Occupational ALARA Inspections
- Inspection Procedure 71124.02 (effective Jan. 2020)
- Radiological Work Planning
- SECY-19-0067 recommended
- Verification of Dose Estimates retiring IP 71124.02
- Implementation of ALARA Work Controls
- Staff will continue IP 71124.02
- Radiation Worker Performance inspections pending a Commission decision.
- Problem Identification and Resolution
- Quartiles - Industrywide data is used to develop plant-specific, three year averages for collective dose and to develop dose quartiles
- Guides planning of inspection efforts
- Used in assessment of inspection finding significance Slide 6 of 13
Occupational ALARA Inspections
- Inspection effort (hours) generally determined by plant quartile standing
- Also consider scope of radiological work and trends
- IP 71124.02 (effective Jan. 2020) biennial hours range from 32 to 60 (average 46)
- Plants in lowest dose quartile should get the minimum inspection effort
- Plants in highest dose quartile should get the maximum inspection effort
- Plants in middle two quartiles should get 46 hours5.324074e-4 days <br />0.0128 hours <br />7.60582e-5 weeks <br />1.7503e-5 months <br /> (adjusted for effectiveness of ALARA and source-term-reduction efforts)
- Plant-specific, three year average is used to assess significance of ALARA Findings Slide 7 of 13
Pressurized Water Reactor Quartiles Three Year Collective TEDE per Reactor Year PWR Quartiles Plant 2017-2019 (person-rem)
Top 14 1st Quartile Bottom 23 Top 25 2nd Quartile Bottom 30 Top 31 3rd Quartile Bottom 40 Top 40 4th Quartile Bottom 123 (IMC 0609 threshold is 135)
Average per Reactor-Year 32 Slide 8 of 13
Boiling Water Reactor Quartiles Three Year Collective TEDE per Reactor Year BWR Quartiles Plant 2017-2019 (person-rem)
Top 37 1st Quartile Bottom 77 Top 81 2nd Quartile Bottom 104 Top 113 3rd Quartile Bottom 138 Top 139 4th Quartile Bottom 220 (IMC 0609 threshold is 240)
Average per Reactor-Year 113 Slide 9 of 13
ALARA Issue Screening
- ALARA Findings: More-than-Minor, performance deficiencies that concern unplanned, unintended occupational collective dose resulting from a deficiency in ALARA planning or work control (IMC 0609 App C)
- Performance Deficiency: Failure to meet a requirement or self-imposed standard where the cause was reasonably within the licensees ability to foresee and correct; and thus prevent (IMC 0612)
- Minor vs. More-than-Minor Minor (Address with CAP)
No No Unplanned, Unplanned, Yes Yes Yes More-than-Minor Performance Unintended Unintended (Inspection Finding)
Deficiency Collective Dose Collective Dose
>5 person-rem >50% of the planned dose Slide 10 of 13
ALARA Significance Determination Process
- If plant-specific, three year average is threshold, significance of ALARA finding is assessed to be Green (IMC 0609)
- Boiling Water Reactor: 240 person-rem
- Pressurized Water Reactor: 135 person-rem
- If plant-specific, three year average is > threshold, consider the magnitude of the issue and collective dose associated with recent issues
- Magnitude of issue: Did actual dose exceed 25 person-rem?
- No, then a Green finding
- Yes, then a White finding
- Consider recent issues: Were there more than 4 occurrences where actual dose > 5 person-rem and > 50% above dose estimate?
- No, then a Green finding
- Yes, then a White finding Slide 11 of 13
Questions and Discussion edward.stutzcage@nrc.gov micheal.smith@nrc.gov steven.garry@nrc.gov Slide 12 of 13
Regulatory Panel Slide 13 of 13