« ՆախորդըՇարունակել »
I reiterate my point that the HTGR is about ten years behind
the ALWR because of the need for an approximately ten-year
Tong HTGR demonstration project to precede NRC design
certification. Such a demonstration project is not required
for the ALWR.
COMMITTEE ON ENERGY AND NATURAL RESOURCES
Following up on the discussion at the hearing on the
Your concerns about meltdown, graphite fires, and a
containment structure have been considered for many years by
the gas-cooled reactor community including the Nuclear Regulatory Commission (NRC) and overseas high temperature gas-cooled reactor (HTGR) developers. First, it should be
said that meltdown is not an approp
ate description for the
HTGR concept, as HTGR fuel is fully ceramic and its failure,
which is at temperatures in excess of 1600 degrees C is
characterized by fission product diffusion through barriers
that maintain their geometry. The rearrangement of
fissionable material in the core or disruption of the core
itself does not occur. Of course, HTGR fuel failure
potentials and consequences are major concerns.
being addressed in the modular high temperature gas reactor
(MHTGR) by the passive decay heat removal configuration, use
of high temperature fuel, and the control of pathways for fission product transport to the environs.
The graphite fire potential was evaluated by the NRC (with assistance from Brookhaven National Laboratory) during the Fort St. Vrain licensing process, following the Chernobyl accident and in the course of its preapplication review for the MHTGR. The NRC states that it believes that air availability pathways, including flow channels in the core, would not support a sustained or damaging graphite fire even if a containment structure was not provided. The NRC states
that confirmatory experiments might be desirable but has not
yet stated this as a requirement. The Department is renewing
interactions with the NRC and the subject of graphite fires will be included in these forthcoming discussions.
QUESTIONS FROM SENATOR WALLOP
Would you agree that the long-term promise of nuclear energy is essentially unlimited through the development of advanced liquid metal reactor technologies?
It was recognized early in the development of nuclear power
that if nuclear fission energy is to make a large
which can utilize essentially all the fissionable material
available in nature from uranium ore, as opposed to the
current light water, heavy water, and graphite moderated
reactor systems which utilize only about one percent of the