TY - JOUR

T1 - An investigation towards real time dose rate monitoring, and fuel rod detection in a First Generation Magnox Storage Pond (FGMSP)

AU - Jackson, Sarah

AU - Monk, Stephen

AU - Riaz, Zahid

PY - 2014/12

Y1 - 2014/12

N2 - The First Generation Magnox Storage Pond (FGMSP) is located on the Sellafield Nuclear Site, housing legacy spent Magnox nuclear fuel. Some of which has since corroded, forming a layer of Corroded Magnox Sludge (CMS) creating one of the largest decommissioning challenges the UK has faced. In this work the composition, physical properties and potentially high hazard nature of CMS are discussed, as are the gamma emission spectra of spent Magnox fuel rods typical of the ilk stored. We assess the potential use of a RadLine gamma detector to dose rate map this area and provide fuel rod detection. RadLine consists of a small scintillator, fibre optic cable and photon counter. The probe has the unusual advantage of not being electrically active and therefore fully submersible underwater, with the option to deploy hundreds of metres in length. Our experimental method encompasses general purpose Monte Carlo radiation transport code, MCNP, where we describe the modelling of CMS and pond liquor in comprehensive detail, including their radiological spectrum, chemical composition data, and physical properties. This investigation concludes that the maximum energy deposited within the scintillator crystal due to ambient CMS corresponds to a dose rate of 5.65 Gyhr-1, thus above this value positive detection of a fuel rod would be anticipated. It is additionally established that the detectable region is within a 20 cm range.

AB - The First Generation Magnox Storage Pond (FGMSP) is located on the Sellafield Nuclear Site, housing legacy spent Magnox nuclear fuel. Some of which has since corroded, forming a layer of Corroded Magnox Sludge (CMS) creating one of the largest decommissioning challenges the UK has faced. In this work the composition, physical properties and potentially high hazard nature of CMS are discussed, as are the gamma emission spectra of spent Magnox fuel rods typical of the ilk stored. We assess the potential use of a RadLine gamma detector to dose rate map this area and provide fuel rod detection. RadLine consists of a small scintillator, fibre optic cable and photon counter. The probe has the unusual advantage of not being electrically active and therefore fully submersible underwater, with the option to deploy hundreds of metres in length. Our experimental method encompasses general purpose Monte Carlo radiation transport code, MCNP, where we describe the modelling of CMS and pond liquor in comprehensive detail, including their radiological spectrum, chemical composition data, and physical properties. This investigation concludes that the maximum energy deposited within the scintillator crystal due to ambient CMS corresponds to a dose rate of 5.65 Gyhr-1, thus above this value positive detection of a fuel rod would be anticipated. It is additionally established that the detectable region is within a 20 cm range.

KW - MCNP

KW - FGMSP

KW - Sludge

KW - Gamma detector

KW - Submersible

KW - Dose rate monitoring

U2 - 10.1016/j.apradiso.2014.08.019

DO - 10.1016/j.apradiso.2014.08.019

M3 - Journal article

VL - 94

SP - 254

EP - 259

JO - Applied Radiation and Isotopes

JF - Applied Radiation and Isotopes

SN - 0969-8043

ER -