Analysis of measures to enhance safeguards, and proliferation resistance in thorium based fuel fabrication plants

The presence of high energy gamma rays emitted by U232, which is always associated in ppm quantities with reprocessed U233, lends robustness or physical protection to the thorium fuel cycle. India is currently setting up a thorium based fuel cycle for its Advanced Heavy Water Reactor (AHWR). Identification and deployment of suitable extrinsic measures for fuel fabrication facilities would help in strengthening overall proliferation resistance. The extrinsic measures proposed in this paper include several measures which have been identified for the first time. A quantitative assessment of the contribution of these measures to overall safeguardability of the fuel fabrication plant has been carried out. Multi Attribute Utility Analysis (MAUA) has been used to evaluate the Proliferation Resistance (PR) value for two hypothetical facilities, one employing none of these measures and the other employing some or all of these measures. The analysis is based on the expert opinion of designers, operators, quality control managers and implementers of safeguards in fuel cycle facilities. Sensitivity analysis for all the proposed measures has also been carried out to study the effect of the influence of individual measures on the overall proliferation resistance of the fuel fabrication plant. The analysis ranks various safeguards measures based on the importance factor of a measure which is defined as the ratio of overall proliferation resistance with and without the measure. Important measures identified based on ranking are near real time monitoring, automation, safeguards-by-design, dynamic nuclear material accounting, and plant imaging.