NAT_preface.txt

PREFACE:
MOLTEN-SALT REACTORS

ALVIN M. WEINBERG Oak Ridge National Laboratory

Oak Ridge, Tennessee 37830

Received August 30, 1969

The achievement of a cheap, reliable, and safe
breeder remains the primary task of the nuclear
energy community. (In expressing this view, |
suppose | betray a continuing frustration at the slow
progress of fusion research, even though the
Russian success with the tokamak has quickened
the pace.) Actually not much has changed in this
regard in 25 years. Even during World War II,
many people realized that the breeder was central.
It 1s only now, with burner reactors doing so well,
that the world generally has mobilized around the
great aim of the breeder.

As all readers of Nuclear Applications &
Technology know, the prevailing view holds that
the LMFBR 1is the proper path to ubiquitous,
permanent energy. It is no secret that [, as well as
many of my colleagues at ORNL, have always felt
differently. When the idea of the breeder was first
suggested in 1943, the rapid and efficient recycle of
the partially spent core was regarded as the main
problem. Nothing that has happened in the ensuing
quarter-century has fundamentally changed this.
The successful breeder will be the one that can deal
with the spent core most rationally—either by
achieving extremely long burnup, or by greatly
simplifying the entire recycle step. We at Oak
Ridge have always been intrigued by this latter
possibility. It explains our long commitment to
liquid-fueled reactors-first, the aqueous
homogeneous and now, the molten salt.

The molten-salt system has been worked on,
mainly at Oak Ridge, for about 22 years. For the
first 10 years, our work was aimed at building a

nuclear aircraft power plant. The first molten-salt
reactor, the Aircraft Reactor Experiment, was
described 1n a series of papers from Oak Ridge that
appeared in the November 1957 issue of Nuclear
Science and Engineering.

The present series of papers reports the status of
molten-salt systems, and particularly the experience
we have had with the Molten-Salt Reactor
Experiment (MSRE). The tone of optimism that
pervades these papers is hard to suppress. And
indeed, the enthusiasm displayed here 1s no longer
confined to Oak Ridge. There are now several
groups working vigorously on molten salts outside
Oak Ridge. The enthusiasm of these groups is not
confined to MSRE, nor even to the molten-salt
breeder. For we now realize that molten-salt
reactors comprise an entire spectrum  of
embodiments that parallels the more conventional
solid-fueled systems. Thus molten-salt reactors can
be converters as well as breeders; and they can be
fueled with either 2*’Pu or *’U or *°U.

However, we are aware that many difficulties
remain, especially before the most advanced
embodiment, the Molten-Salt Breeder, becomes a
reality. Not all of these difficulties are technical. 1
have faith that with continued enlightened support
of the US Atomic Energy Commission, and with
the open-minded, sympathetic attention of the nu-
clear community that these papers should
encourage, molten-salt reactors will find an
important niche in the unfolding nuclear energy
enterprise.