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DTRA’s advancements in nuclear and radiological detection
A new, more complex nuclear age has begun. Echoing the tensions of the Cold War amid rapidly evolving nuclear and radiological threats, preparedness in the modern age is a contest of scientific innovation. The Research and Development Directorate (RD) at the Defense Threat Reduction Agency (DTRA) is charged with winning this contest.
P. N. Maya, S. P. Deshpande, P. Prajapati, A. K. Tyagi, H. L. Swami, C. Danani, P. Chaudhuri, M. Ghate, V. Mehta, P. K. Sharma
Fusion Science and Technology | Volume 82 | Number 4 | May 2026 | Pages 775-791
Research Article | doi.org/10.1080/15361055.2025.2575708
Articles are hosted by Taylor and Francis Online.
A gross electricity–producing compact pilot plant (PP) is essential in addressing the science and technology gap between present-day tokamaks including ITER to a DEMO and power plant in the staged approach to DEMO. Key driving features for nuclear analysis requirements for a compact fusion PP of 3.6-m major radius, 300-MW fusion power with 0.8 electric gain and 20% (75 days) availability are presented. Modular blanket maintenance requirements and compactness require a gap between the outboard blanket and vacuum vessel for allowing maintenance through the vertical ports, and a scheme is presented. The requirements arising from the plant layout, breeding and shielding blankets, and maintenance scheme and the regulatory considerations are discussed. Because of the space constraints, a breeding blanket is possible only on the outboard, and a preliminary one-dimensional nuclear analysis of the plant is carried out with a helium-cooled solid breeder. For 75 days of continuous operation, the displacement damage in the first wall is about 1.5 displacements per atom (dpa), and the neutron fluence at the magnet insulator is 9.1 × 1017 n/cm2. The total dpa of the structural material in a campaign of 3 full-power years (FPY) were about 22, which is almost the limiting dpa of reduced-activation ferritic-martensitic steel. The analysis indicates that further optimization of the shield blanket is essential for the target operational lifetime of 3 FPY. The total tritium breeding ratio (TBR) obtained is 0.92, which could be reduced to 0.5 to 0.6 by considering the reduction in the blanket coverage area. The target TBR is set to 0.6 for the analysis. To meet this target TBR, an initial tritium inventory of about 2.7 kg is required for 1 calendar year of operation (0.2 FPY) where the exhaust processing time is about 1 day and the time for tritium extraction from the blanket is about 10 days.