A bounding estimate of neutron dose based on measured photon dose around single pass reactors at the Hanford site.
Neutron and photon radiation survey records have been used to evaluate and develop a neutron to photon (NP) ratio to reconstruct neutron doses to workers around Hanford's single pass reactors that operated from 1945 to 1972. A total of 5,773 paired neutron and photon measurements extracted from 57 boxes of survey records were used in the development of the NP ratio. The development of the NP ratio enables the use of the recorded dose from an individual's photon dosimeter badge to be used to estimate the unmonitored neutron dose. The Pearson rank correlation between the neutron and photon measurements was 0.71. The NP ratio best fit a lognormal distribution with a geometric mean (GM) of 0.8, a geometric standard deviation (GSD) of 2.95, and the upper 95 th % of this distribution was 4.75. An estimate of the neutron dose based on this NP ratio is considered bounding due to evidence that up to 70% of the total photon exposure received by workers around the single pass reactors occurs during shutdown maintenance and refueling activities when there is no significant neutron exposure. Thus when this NP ratio is applied to the total measured photon dose from an individual film badge dosimeter, the resulting neutron dose is considered bounded.
National Institute for Occupational Safety and Health (NIOSH), Office of Compensation Analysis and Support (OCAS), Robert A. Taft Laboratories, 4676 Columbia Parkway, Cincinnati, OH 45226, USA. ttaulbee@cdc.gov
Timothy D
TD
Taulbee
Samuel E
SE
Glover
Gregory V
GV
Macievic
Mickey
M
Hunacek
Cheryl
C
Smith
Gary W
GW
DeBord
Donald
D
Morris
Jack
J
Fix
D003625:Data Collection; D004784:Environmental Monitoring; D005843:Geography; D006801:Humans; D008297:Male; D015233:Models, Statistical; D009502:Neutrons; D009688:Nuclear Reactors; D016273:Occupational Exposure / Q000009:adverse effects / Q000032:analysis*; D017785:Photons; D011829:Radiation Dosage; D018570:Risk Assessment; D013997:Time Factors