"Assessment of the Fingerprinting Method for Verification of Spent Fuel in MACSTOR KN-400 CANDU Spent Fuel Dry Storage,"
M.S. Thesis, Nuclear Engineering, Texas A&M University, College Station, TX (2012).
The Wolsong reactor site in republic of Korea currently has four
CANDU reactors. The spent fuel bundles are transferred to an
interim dry storage facility after cooling in water pool. However,
the site does not have enough space for further extension of its
existing interim storage facility. Hence, Korea Hydro and Nuclear
Power has built a new modular type of dry storage facility, MACSTOR
KN-400. The safeguards regulations of the IAEA demand an effective
method of spent fuel verification at the MACSTOR KN-400 storage
facility in the event of any loss of continuity of knowledge.
Central and peripheral structures of the MACSTOR KN-400 along with
the re-verification tube were modeled using the radiation transport
code, MCNP. Central and peripheral structures have different types
of re-verification systems. Both, gamma and neutron simulations
were carried out using these MCNP models developed for MACSTOR
KN-400. CANDU spent fuel bundles with burn-up of 7.5 GWD/t and 10
years cooling time were considered for the radiation source term.
MCNP gamma-transport simulations were done by integrating CZT
detector inside the re-verification tube. Gamma-transport
simulations for different spent fuel diversion scenarios were
It was observed that for diversion scenarios wherein most of the
bundles are removed from the inner portions of the basket, it was
difficult to conclude whether diversion has taken place based on
the change in gamma radiation signals. Similarly neutron transport
simulations were also carried out by integrating He3 detector
inside the re-verification tube. Results obtained from
neutron-transport simulations for various spent fuel diversion
scenarios were encouraging and indeed indicated higher sensitivity
for diversion of fuel bundles. The study concludes that as the
fingerprinting method based on gamma signals alone does not
adequately protect diversion of fuel bundles inside baskets,
alternative fingerprinting method such as the one with neutron
signals should be explored.
Associated Project(s):Assessment of the Fingerprinting Method for Verification of Spent Fuel in MACSTOR KN-400 CANDU Spent Fuel Dry Storage