Dose Investigation and Dose Estimates Flashcards
Purpose of Dose Investigation
Used any time a dosimeter measurement is in question, determine if a dose stands on its own or has to be estimated
Dose Estimate
Assigns a dose when dosimeter measurement are not able to. Dose estimate is required to estimate all the occupational exposures the individual should have received. For personnel exposed to NNPP sources, a dose estimates for photon deep dose equivalent. shallow dose equivalent, and neutron deep dose equivalent is required.
Dose investigation must be
scientifically based, technically accurate, thoroughly documented, and retained indefinitely
Do all dose investigations require a dose estimate
No, but all dose estimates require a dose investigation
Dose investigation and estimate is initiated under the following conditions
Primary TLD lost, damaged, or destroyed
entering a radiation area without a TLD
Assign Dosimeter worn by another individual
Suspect TLD reading, unexpectedly high or low
technical, electronic, software, or mechanical problem is noted during dosimeter processing
Primary dosimetric device was not worn on the correct location on the body for work radiation performed
Operational conditions prevent evaluation of the primary dosimeter in a timely manner
Significant difference between primary and secondary dosimeter (30/30) rule
Differ by more than 30% or more and primary is >100mrem
Differ by more than 30mrem or more and primary is <100mrem
Required documents for DI/DE
Reason investigation was performed
Signed and dated worker’s statement
Glow curve
All applicable supporting documentation (survey records, ERC’s, Figures)
Will include shallow, deep, and neutron dose equivalents
Contents of Workers statements
Individual account of what happened
Description of the individual activities during monitoring period
Individual shall indicate on a survey map the areas frequented and time, body position
Any exposure to radiation sources not associated with radiological controls program. (medical, dental)
Any abnormal dosimeter storage conditions or abnormal TLD body location that may affect the evaluation/estimate
If other monitored personnel were present with individual or if individual previously performed similar work during the same monitoring period
Documentation of DI/DE
Unclassified manner, second copy of the report shall be separately filled along with necessary supporting survey records that may contain classified information or unclassified Naval Nuclear Propulsion information
The estimated dose is recorded with exposure period blocks 7 through 13 on the NAVMED 6470/10. Dose investigation without an estimate does not require
Annotated remarks on /10
reason why
dose estimate
basis for the dose estimate
Period covered by estimate
Completion Deadline
Preliminary investigation shall be completed within 10 days. Based survey or previous history
Final investigation will be completed within 14 days of receipt of final exposure information or 14 days upon returning to homeport
Preliminary estimate doesn’t need to be retained once final report replaces it, but final estimate report must document when preliminary report was completed
Per RCFS, an incident report to NAVSEA 08 is required if a dose estimate is performed due to a member entering a radiation area without TLD, and the assigned dose is greater than 1mrem
Methods for determining dose
Secondary dosimeter
Doses from similar work
- collect TLD’s from 3 members who performed similar work
- Re-issue TLD to those individuals
- Stow TLD in low background areas
- Document on /3
Exposure Time and Dose rate study: Survey map
