E.T. Cheng,
TSI Research Inc., 225 Stevens Ave., Solana Beach, CA 92075
Y.-K. M. Peng,**
Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, NJ 08543
D.K. Sze,
Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL 60439
S. E. Berk,
U.S. Department of Energy, Germantown, MD 20874
A small plasma based volumetric neutron source (VNS) could provide a test environment for fusion power blanket technology in ways complementary to the tests planned for ITER. Given capabilities of high neutron fluence, the VNS could be used to test the mean-time-to-failure of test blankets built with the power reactor relevant structural and breeding materials.
A recent study has identified innovative design features for a spherical torus (ST) based VNS to enable the development of capability for achieving high neutron fluence. This capability could in turn permit in a power reactor relevant environment (1) obtaining lifetime limiting factors for power core components including first wall, divertor, and blanket, and (2) developing component operating capabilities at progressing levels of neutron wall-loading.
The design concept takes advantage of the low magnetic field and compact plasma to implement full remote replacement of the center leg of the toroidal field coil, the divertor, the first wall, the breeding shield, and the test blanket modules. The high performance anticipated for the ST plasma permits large physics margins for the required neutron wall loading of 2 MW/m2, while still allowing a long-term power reactor relevant physics performance goal of 5 MW/m2 with reduced margins.
At the initial stage of operation, only modest neutron wall loading (0.5 MW/m2) would be attempted. The device would begin with adequate reliability the test and development of key components and necessary material combinations. After gaining significant testing data and operating experience, components with improved performance and reliability would be installed to utilize increased levels of plasma performance. Success in achieving reliable operations at 2 MW/m2 in wall loading would fulfill the goals of the VNS; success at 5 MW/m2 would permit component testing for the demonstration power plants. This approach of ST-VNS provides a realistic opportunity for the ultimate demonstration of safe, reliable, and environmentally attractive fusion systems.
*Work supported by U.S. Department of Energy, Small Business Innovative Research Grant No. DE-FG03-95ER82098.
**On assignment from Oak Ridge National Laboratory, P.O. Box 2009, Oak Ridge, TN 37831.