Neutron spectra and dose equivalent inside reactor containment

Neutron spectra were measured at several locations inside the containment vessel at six different power reactors. The purpose of this study is to provide neutron spectra and dose equivalent data to increase the accuracy of the interpretation of dose equivalency when using neutron dosimeters and neutron monitoring instruments at commercial nuclear facilities. A multisphere spectrometer system with seven different neutron detector configurations was used to measure neutron spectra at several locations inside containment at the various sites. These data were analyzed using the computer code LOUHI-78 which provides spectra as a function of neutron energy and lethargy. Kerma and dose equivalent rates are also computed by the code from the same data. Spectral and dose equivalent information are presented for both LWR types. Measurements were also conducted at several locations with tissue equivalent proportional counters (TEPCs). Event size spectra from the TEPC and quality factors derived from these spectra are presented for PWR sites and for high and low dose rates. Spectral data are correlated to instrument readings and personnel dosimeter results obtained at selected work locations by making exposures using H2O phantoms. Several different types of neutron dosimeters were used for these measurements and include NTA film, track etch dosimeters, and albedo systems. Responses of the various instruments and personnel dosimeters are discussed. (author)