Behavior of the DataSeal in mixed radiation fields

Tamper-indicating seals have important application in many areas of the nuclear non-proliferation regime established by the Nuclear non-Proliferation Treaty (NPT). These seals must operate reliably in extremely harsh environmental conditions including high radiation fields. Due to experience with inadequately tested equipment, the International Atomic Energy Agency (IAEA) has established an extensive test regime for all equipment used for nuclear safeguards purposes, which includes testing in strong ionizing radiation fields. Therefore, the Atominstitute of the Austrian Universities (ATI) in cooperation with the IAEA (Section of NDA and Seals) has completed a series of irradiation tests (based on Safeguards test procedure) on a new seal product (an active radio frequency tamper indicating seal) that was designed for use in the trucking industry. These irradiation tests were: thermal neutron irradiation test at thermal column, fast neutron irradiation test in elevator and gamma irradiation test in the spent fuel storage. The tests results indicate that these seals may be used in high-class radiation fields. However, they will not survive in radiations fields that are present in some special applications. In strong gamma radiation fields, it was found that the instruments emit spurious signals and fail after a cumulative dose of about 350 gy. Similarly, the seals failed after an average thermal neutron fluence of 4,968 x 1013 n/cm2 . No fast neutrons are present at the thermal column, therefore, only the thermal neutron dose was calculated there; only a fast neutron spectrum with a negligible thermal contribution is present in the elevator; no major technical problems were observed with the data reader; the connectors used for the seal wire are not stable/secure enough; vibration in the reactor hall caused the seal to record tampering events; the seals, the program and the results were checked every day during and after irradiation; activation analysis shows that 82Br is the only material used in these seals that is prone to neutron activation, The absorption of thermal neutrons in each layer of the seal's structure has been demonstrated using neutron tomography. (nevyjel)