NUREG-1537, Part 2 - NRC

APPENDix 18 1
* The design bases changes in structures, systems, and components of the
facility required by the conversion from HEU fuel are specified for use in
the subsequent, applicable SAR sections.
* The LEU design bases for structures, systems, and components have not
changed from those previously established for the HEU facility; This is
acceptable for the LEU-fueled reactor facility as these design bases will be
verified in subsequent, applicable SAR sections.
4 REACTOR DESCRIPTION
4.1 Reactor Facility
This s o description should provide the reviewer with a brief overview of the
design and operating characteristics of the existing HEU-fueled reactor and
comparisons with the proposed LEU-fueled reactor. Any significant safety-related
modifications should be emphasized and the reasons they are required for the
conversion should be summarized. Physical changes in the fuel characteristics and
the balance of the reactor should be described briefly. This section should contain
a discussion as to whether only the fuel will be changed and whether any
significant operational characteristics or procedures will be changed for the
proposed LEU-fueled reactor. The detailed discussions and analyses of these
changes should be reviewed and evaluated in appropriate sections of this safety
analysis.
4.2 Reactor Core
Areas of Review (Sections 4.2.1-4.2.6)
In converting a non-power reactor from HEU to LEU fuel, most of the physical
and operational changes are expected to be associated with the reactor core. The
core includes the fuel, the neutron moderator, the fuel coolant, the neutronabsorbing
sections of the control elements, the neutron reflector, the neutron
startup source, and any in- core experimental ficilities.
Areas of review for the reactor core include an overview of the configuration of
the proposed LEU-fueled core and comparison with the existing HEU-fueled
reactor (e.g., critical masses and operational masses of uranium-235). Figures
should show the locations and geometries of the components in the two cores and
lists should provide important design parameters and operational characteristics.
The design bases and functional characteristics of any core systems or components
for which significant changes are proposed should be reviewed, as well as reasons
that the changes are required to accommodate the conversion from HEU fuel. In
NUREG-1537, PART 2 6 REV 0.2/96
NUREG- 1 537, PART 2 6 REV 0, 2/96