channels, 12 inches in width (30.48 cm), through which the monorail system runs. Each channel
is separated by a concrete divider that is 12 inches in width (30.48 cm) and 30 inches high (76.2
cm), as shown in Figure 2.1 The current age of the facility and degradation due to corrosion
problems have led to failures of the monorail fuel storage system, such that the loss of spacing
provided by the monorail system can no longer be considered a contingency.
Fuel is currently stored in the north and middle basins by one of two methods. The first
method, common to most of the navy fuels, consists of fuel hanging from a single hook
arrangement. A standard is placed through the center of the fuel assembly and hung directly on
the hook. In the second method, which is used for the BORAX V fuel, the fuel assemblies are
placed into a bucket that is then hung from the monorail system.
An example of a monorail hanger system and a typical bucket is given in Figure 3.1 The
buckets are constructed of either aluminum or stainless steel, depending upon fuel types stored in
the bucket, thus assuring materials compatibility.
The failure of the monorail storage system is directly related to the corrosion problems in
the north and middle basins. Earlier corrosion problems led to modification of some monorail
hangers. Some of these modifications included the cutting of carbon steel hanger systems and the
replacement of the carbon steel hooks with stainless steel hooks.
In the process of attaching the stainless steel hooks to the carbon steel hanger assemblies,
a galvanic couple was created. With existing corrosion problems and loss of structural integrity
due to the galvanic couple, the load present caused a failure to occur.
Due to the loss of the engineered safety feature (spacing) provided by this system,
evaluation of a new fuel configuration was required. Considered in this evaluation are various
arrangements of BORAX V fuel elements without the spacing that was once maintained by the
monorail storage system. In addition to the loss of spacing between storage buckets, the