Quantitative Evaluation of Contamination Consequences QECC Database

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Quantitative Evaluation of Contamination
Consequences (QECC) Database

• April 22, 1998 Air Monitoring Users Group
• Savannah River Site, South Carolina

Daniel J. Strom and Charles R. Watson Risk
Analysis Health Protection, Pacific Northwest
National Laboratory Richland, Washington Work
supported by the U.S. Department of Energy under
Contract No. DE-AC06-76RLO 1830
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Overview

• Introduction
• Quantitative Evaluation of Contamination
  Consequences (QECC) approach
• Previous Work for NRC-NMSS
• Data Sources
• Elements of the QECC Database
• QECC Outcome Measures
• Data Needs
• Future directions

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Introduction

• Radioactive Contamination So What?
• Need quantitative answers
• Contamination Control should be affordable the R
  in ALARA
• Are current standards (RG 1.86, 10 CFR 835 App.
  D, ANSI N13.12) adequate to protect human health,
  or are they overkill?

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Why Control Contamination?

• Protect human health (worker public)
• Progress towards desired facility end-state (DD)
• Reduce PPE use (increase operational efficiency,
  work faster, less heat stress, save on laundry
  operations)
• Meet performance indicators
• Avoid incidents that require reporting
• Provide defense-in-depth
• Make workers, public, regulators feel better
• Minimize waste through no rad added policy
• Because we can

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QECC Approach

• Goal quantitative lessons learned (radiological
  chemical) emphasizing human health consequences
• Assemble, organize, analyze historical data
• accidents in literature (IAEA, NRC, journals)
• DOEs Occurrence Reporting and Processing System
  (ORPS)
• NRCs Information Notices other sources
• Tap previous research (journals, reports)
• Future collect info thats out there already

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QECC Outcome Measures 1

• Intake per Surface Unit
• Intake per Airborne Unit
• Intake per Skin Unit
• Fraction-Taken-In
• Fraction-Taken-On

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QECC Outcome Measures 2

• Time-and-proximity Factor (Unshielded)
• Representativeness of Air Samples - GA/BZ
• Representativeness of Air Samples - BZ/Intake
• Performance of Respirators under Field Conditions
• Resuspension Factor and Related Quantities

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Elements of QECC Database Key Fields

• Events - highest level
• Situations - may be several associated with event
• Persons - may be many associated with situation
• Agents - radionuclides, chemicals
• Situagents - agents in context of a situation
  (includes how much of agent)

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Other Data

• Records associated with a situation
• airborne contamination
• surface contamination
• room volume, surface area
• Records associated with persons
• skin contamination
• organ insult (dose, chemicals, activity, etc.)
• medical outcomes

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Data Needs 1

• Completeness is a real problem
• the people involved in the event knew everything
  we need to know, but rarely report it
• Reporting as less than or undetectable
• known as censoring data
• without decision level (DL LC)
• many reports confuse DL with minimum detectable
  amount (MDA LD)

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DL and MDA
lt DL
lt MDA

• Never compare data with minimum detectable amount
  (MDA LD) compare data with decision level (DL
  LC)

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Data Needs 2

• type and amount of material in process
• the nature, extent and amounts of removable and
  total surface contamination
• air sample results
• the nature of personal protective equipment in
  use

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Data Needs 3

• description of work or incident and amount of
  time workers were present
• the minimum detectable amount (MDA), decision
  level (DL), and uncertainty for each measurement
  method used

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Viewing a Measurement as an Object

• An object is a collection of properties related
  to each other
• Example a vector quantity (x, y, z, ict)
• Example a cell in a spreadsheet
• content
• format e.g., date, currency, text, fixed,
  scientific (X.XXEYY)
• font, color, border, fill,
• alas, no uncertainty

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Properties of the Measurement Object

• 1. Physical quantity
• 2. Magnitude (central tendency)
• 3. Units
• 4. Provenance and nature of number
• 5. Uncertainty
• 6. Nature of uncertainty
• 7. Variability
• 8. Nature of variability

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Data Needs 4

• for each individual involved
• personal protective equipment in use
• intakes
• ontakes (skin contamination)
• bioassay results
• nasal smear results
• doses
• medical outcomes (if any)

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Sources of Data

• IAEA reports
• NRC Information Notices
• NRC NUREGs
• DOE Occurrence Reporting and Processing System
  (ORPS)
• Peer-reviewed literature
• Nuclear Power industry (?)

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NUMEC Pu exposures (Caldwell 1968)
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Correlation of In Vivo Bioassay with Air Sample
Predictions (Uranium Fuel Fabrication)
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Previous Experience for NMSS

• Sealed Source accidents
• Outcome variables
• Time-and-Proximity Factors
• Fraction-Taken-In
• Historical data all were below worst-case
  scenarios means were orders of magnitude less

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Conclusions

• Real world is less hazardous than worst-case
  models predict
• QECC Database is powerful analytical tool
• Data we need are already out there, but rarely
  recorded
• Data need to be complete for quantitative lessons
  to be learned