NUREG-1864 A Pilot Probabilistic Risk Assessment Of a Dry Cask Storage System At a Nuclear Power Plant
Nuclear Regulatory Commission (2007-03)
This Page: https://copswiki.org/Common/M1800
Media Link: https://copswiki.org/w/pub/Common/M1800/ML071340012.pdf
More Info: Nuclear Waste
This is a horrible example of how far off our Nuclear Regulatory Commission is in estimating problem. This PRA has fatal flaws, such as:
FATAL FLAW 1: No appreciation of Chloride Induced Stress Corrosion Cracking (CISCC) or any other sort of corrosion.
The MPC, which acts as the confinement boundary for the HI-STORM dry cask storage system, is
constructed entirely from austenitic stainless steel Types 304, 316, 304L, or316L. All of these stainless
steel grades are corrosion resistant in high-humidity and industrial environments. Therefore, coastal and
industrial atmospheres should have no effect on the confinement ability of the MPC (Reference 51 -- 51. American Society for Metals, "Corrosion Resistant Materials," Metals Handbook Desk Edition, Materials Park, Ohio, 1985.)
FATAL FLAW 2: ISFSI is in unreasonably secure area.
The assumptions in the PRA are BEST CASE rather than WORST CASE.
Other than a spur track from a railway line, there are no railway lines near the route
of the storage cask from the reactor building to the storage pad or at the storage pad.
Within a radius of 8 km (5 miles) of the subject plant, there are no manufacturing or chemical
plants, refineries, storage facilities, mining operations, military bases, military bombing ranges,
aircraft low-level flight patterns, missile sites, transportation facilities, oil or gas wells,
or underground storage facilities. The area within this radius of the subject plant is mostly rural;
the land is either residential or agricultural. The area is not expected to change significantly
in the foreseeable future.
FATAL FLAW 3: No aging effects
Used a thick cask in a test that only could evaluate the aging of the contents, not the thin canisters used in the rest of the evaluation.
220.127.116.11 Aging Effects
To evaluate possible aging effects, a CASTOR-V/21 dry storage cask was examined for degradation
(Reference 6). This cask was produced for use in testing aging effects on long-term dry cask storage.
(This cask design was not put into production.) The examination consisted of remote indirect visual
examination [cask internal, lid seals, and pressurized-water reactor (PWR) spent fuel assemblies]
and temperature measurements of selected spent fuel assemblies. Interior crud samples were taken,
and surface gamma and neutron dose rates were measured. Selected fuel rod assemblies were removed
from One assembly, visually examined, and subjected to nondestructive, destructive, and mechanical
examination. The helium inerting gas was sampled for analysis.
After 14 years of storage, no evidence of degradation that would affect the performance of the cask
or integrity of the fuel was evident. The fuel was intact; there was no evidence of creep or rod bow.
Crud found on the fuel rods was attributed to oxidized steel while the fuel was in the reactor; none of
the oxidation is attributed to dry storage. Of 16 stitch welds that attached borated plates to the basket,
15 were cracked. The stitch weld cracking was attributed to the tight fit of the assemblies in the basket,
not to storage. Small amounts of air mixed in with the helium were attributed to the process of inerting
While the results for the CASTOR-V/21 dry cask suggest that there will be no significant aging effects
for the subject cask, it is unclear whether the two casks experience similar conditions. Accordingly,
except for possible cask and fuel corrosion (see Section 8.3), aging effects are beyond the scope
of this study.
- ML071340012.pdf: NUREG-1864 A Pilot Probabilistic Risk Assessment Of a Dry Cask Storage System At a Nuclear Power Plant