It is suggested that/the tangential exposure tube that passes underneath
the reactor always be loaded witha neutron absorbing "rabbit"
which can be made to stop directly under the reactor to provide
aadditional emergency shut down action except when it
used for a specific "rabbit" experiment. A boron loaded "rabbitt"
should be rather easy to construct. It would of course have to be
very carefully sealed so as to minimise any possible dispersal of
boron that would reduce the reactivity of the reactor unintentionally.