Flood Protection and Emergency Operations Plans

DOE-STD-1020-2002

maximum depth of water that could accumulate if the primary-drainage system is blocked (Refs.

4-1, 4-14, and 4-15).

Roof-drainage systems should be designed according to applicable regulations. The

drainage system should be verified as part of the site analysis for the DBFL (discussed above).

In the case of rainfall, a limiting check of the roof system structural design should be made.

Ponding on the roof is assumed to occur to a maximum depth corresponding to the level of the

secondary drainage outlet system (i.e., assuming the primary system has clogged). As part of

this evaluation, the deflection of the roof due to ponding must be considered. The design of the

roof should be adequate to meet the applicable codes. Design criteria for snow and rain-snow

loads are defined in the model building codes and standards.

The DOE criteria specify the importance factors that should be used to scale snow loads

in the design. In the design of roof systems for snow loads, the importance factor for

Performance Categories 1 and 2 is 1.0. For Performance Categories 3 and 4 an importance

factor of 1.2 should be used.

4.3.4 Flood Protection and Emergency Operations Plans

For SSCs that may be exposed to flood hazards (i.e., are located below the DBFL), a

number of design alternatives are available. Depending on the flood hazards that an SSC must

withstand, various hardening systems may be considered. These include,

structural barriers (e.g., exterior building walls, floodwalls, watertight

doors),

wet or dry flood proofing (e.g., waterproofing exterior walls, watertight

doors),

levees, dikes, seawalls, revetments, and

diversion dams and retention basins.

The design of structural systems (i.e., exterior building walls) shall be developed in

accordance with applicable regulations. Waterproofing requirements are also given in applicable

design standards. Guidelines for the design of earth structures such as levees, seawalls, etc. are

provided in References 4-8, 4-16, and 4-17. Guidance for the design of diversion dams and

retention basins can be found in U.S. Army Corps of Engineers, U.S. Bureau of Reclamation,

Soil Conservation Service reference documents (Refs. 4-12 and 4-16).

Emergency operation plans are required in cases where the health and safety of on-site

personnel must be provided for and where the facility must be secured to prevent damage or

interruption of operations. The elements of an emergency operation plan are:

flood recognition system - capability to identify impending floods and

predicting their timing and magnitude.

warning system - procedures and means to provide warning to those in the

affected areas.

4-13