Building Protection Against External Ionizing Fallout Radiation

2019-10-09T23:58:41Z (GMT) by Michael Dillon Steven G. Homann
A nuclear explosion has the potential to injure or kill tens to hundreds of thousands of people through exposure to fallout (external gamma) radiation. Existing buildings can protect their occupants (reducing external radiation exposures) by placing material and distance between fallout particles and indoor individuals. This protection is not well captured in current fallout risk assessment models and so the US Department of Defense is implementing the Regional Shelter Analysis methodology to improve the ability of the Hazard Prediction and Assessment Capability (HPAC) model to account for building protection.

This HPAC improvement effort requires accurate estimates of building protection for common building construction types worldwide. Building protection against outdoor radiation sources has been studied for seven decades within the context of (a) nuclear fallout protection and the (b) remediation of nuclear power plant accidents and other cases of wide-spread radiological contamination. The building types and corresponding protection factor estimates currently in use are primarily based on work performed during (a) the early cold war and (b) the remediation of the Chernobyl and Fukushima nuclear power plant accidents. While these prior building protection estimates describe some building types well, they do not cover the range of worldwide building construction. This is problematic as reasonable variations in building protection can significantly alter the number of people adversely affected by nuclear fallout.

This report supports the HPAC improvement effort by identifying a set of building attributes (next page) that, when collectively specified, are sufficient to calculate reasonably accurate, i.e., within a factor of 2, fallout shelter quality estimates for many individual buildings. The set of building attributes were determined by first identifying the key physics controlling building protection from fallout radiation and then assessing which building attributes are relevant to the identified physics. This approach was evaluated by developing a screening model (PFscreen) based on the identified physics and comparing the screening model results against the set of existing independent experimental, theoretical, and modeled building protection estimates. In the interests of transparency, we have developed a benchmark dataset containing (a) most of the relevant primary experimental data published by prior generations of fallout protection scientists as well as (b) the screening model results.