Latest Radio-active Particle finds At Dounreay

18th December 2021

Glossary of terms
Term Explanation
ID number Unique reference number given to each particle
Date Date on which the particle was found
Easting East co-ordinate of particle find in UK national grid
Northing North co-ordinate of particle find in UK national grid
Depth Approximate depth in centimetres at which the particle was located.
Cs137 Bq Content of Caesium 137 activity in the particle, measured in becquerels.
Co60 Bq Content of Cobalt 60 activity in the particle, measured in becquerels
Nb94 Bq Content of Niobium 94 activity in the particle, measured in becquerels
Am-241 Content of Americium-241 activity in the particle, measured in becquerels
Type Type of particle. Particles are generally of 3 main types depending on the origin of the particle, but a fourth type, denoted by U, has also been identified.
Type of particle code Type of particle
DFR Originated from Dounreay Fast Reactor
MTR Originated from a Materials Test Reactor
SS Stainless steel, originated from DFR or PFR (Prototype Fast Reactor) cladding materials
U Contain irradiated uranium oxide, which could have originated from MTR or DFR fuel
Note: particle type is determined from analysis. Where required SEM/Edax is carried out, with the agreement of SEPA, on selected particles.

Comments: Some particles, when separated in the laboratory from the associated sediments, are found to comprise more than 1 fragment. The number of fragments are identified.