(407d) Assessing Consequences of Chemical Releases on Control Room Habitability Using Habit 2.1

HABIT is a package of computer codes designed to assist in the evaluation of control room habitability in the event of accidental spills of hazardous materials in the vicinity, and is part of the U.S. Nuclear Regulatory Agency’s Radiological Protection Computer Code Analysis and Maintenance Program (RAMP). HABIT was originally developed at Pacific Northwest laboratory (PNL) to model atmospheric dispersion based on standard passive dispersion models. In addition to an extensive update of its user interface, HABIT 2.1 was recently extended to include the effects of denser-than-air contaminant cloud behavior using the SLAB and DEGADIS models. This paper summarizes how the previous HABIT source models (instantaneous and finite duration releases) were used to generate inputs to SLAB and DEGADIS. Model results are presented for a postulated chlorine release event, and the importance of denser-than-air behavior is discussed including the potential impact of the air intake height on the concentration of chlorine inside the control room.