A Comparative Analysis of the Radiological Consequences of Routine Operation of a Fission Research Reactor and the Fusion Ignition Experiment IGNITEX

The IGNITEX experiment is being designed to study the physics of ignited plasmas. Over the service lifetime of the device (two years), it is expected to be pulsed 2,000 times with each pulse producing 150 MW of DT fusion power for approximately five seconds. Neutrons from each pulse will activate the magnet structure, liquid nitrogen in the cryostat and test cell air. Radioactive effluents from IGNITEX will primarily result from activated air, activated liquid nitrogen, and tritium. To provide a perspective for evaluating the doses resulting from the gaseous effluents from IGNITEX, the doses from the gaseous effluents from a 1 MW fission research reactor were also calculated.For both facilities, the primary effluents are airborne. Two dose receptor locations were assumed. The first was taken to be the building nearest to the facility and it was taken to be 400 m distant. The second was the nearest residence and it was taken to be 1.2 km distant. For the dose calculations, the air stability was assumed to be neutral and the dose receptors were assumed to be in the direction of a 4.5 m/sec prevailing wind. All releases were taken to be at ground level. The equations used to calculate the annual doses were taken from Regulatory Guide 1.109. The gaseous effluents from IGNITEX were assumed to consist of ⁴¹Ar, ¹³N, ¹⁶N, ¹⁴C, and ³H. Effluents from the fission research reactor consisted of ⁴¹Ar, gaseous and semi-volatile fission products. Each facility's dose was compared to the 10CFR50 Appendix I limits. In each dose category, with the exception of the thyroid dose the dose resulting from the operation of IGNITEX were more than that of the fission reactor. The increased doses were due primarily to the activated nitrogen releases.