Details are discussed of a volume neutron source for testing assemblies suc
h as blanket sections in a 14 MeV neutron environment. This neutron source
is based on the spherical tokamak. The experimentally confirmed ability of
the spherical tokamak to reach very high plasma pressures makes it ideally
suited as the basis for a very compact neutron source (R similar to 0.7 m,
I-P similar to 7-12 MA). An outline engineering design for such a device ha
s been established and a detailed thermo-hydraulic and stress analysis is p
resented, which demonstrates its engineering feasibility. Availability has
been estimated by a bottom-up approach and shows a fluence target of 6 MWa
m(-2) is achievable over a 10 year operational life. Detailed 3D neutronics
calculations establish damage and material activation rates and show that
the neutron spectrum is very close to that expected in ITER. (C) 1999 UKAEA
Fusion. Published by Elsevier Science S.A. All rights reserved.