# Projects

## Shielding Calculations for the Canister Storage Building

The Canister Storage Building(CSB) shielding calculations are an example of an extreme radiation streaming problem. They are typical of the calculations PNNL performs for a variety of problems and clients.

In this project, PNNL helped evaluate the suitability of the CSB on the Hanford Site for storage of interim high level waste (IHLW) canisters. The CSB is an existing building that had been designed originally for the storage of spent nuclear fuel. Thus, it was necessary to determine if the design of the building was adequate for storage of IHLW canisters. The CSB consists of three below-grade storage vaults and a single above-grade operating deck area. The IHLW canisters will be stored in vaults #2 and #3. The vaults of the CSB will be cooled by natural air circulation. Heated air will exit the vaults through an exhaust stack.

Staff used the Monte Carlo n-particle transport code system, MCNP Version 4C, to calculate the radiation dose just outside the exhaust stack. Environmental dose rates for distances up to 50 feet from the base of the exhaust stack were also calculated. Preliminary calculations indicated that more shielding would be required at the base of the exhaust stack than was provided by its nominal design thickness.