Effects of Earthquakes

DOE-STD-1020-2002

in the adjacent SSCs pounding together; (3) displacements of adjacent SSCs during seismic

response resulting in failure of connecting pipes or cables; (4) flooding and exposure to fluids

from vessels or piping systems ruptured as a result of earthquake motion; and (5) effects of

seismic-induced fires.

The occurrence of an earthquake affects many or all SSCs in a facility. Hence, it is

possible to have multiple seismic-induced failures of SSCs. These common cause effects must

be considered in design or evaluation. For example, multiple failures in a tank farm can result in

loss of contents greater than that held in any single tank which in turn could overflow a retention

berm and/or flood adjacent SSCs. The effects of this large quantity of tank contents on SSCs

must be considered.

Earthquake ground shaking also affects building contents and nonstructural features

such as windows, facades, and hanging lights. It is common for the structure to survive an

earthquake without serious structural damage but to have significant and expensive damage of

contents. This damage could be caused by overturned equipment or shelves, fallen lights or

ceilings, broken glass, and failed infill walls. Glass and architectural finishes may be brittle

relative to the main structure, and they can fail well before structural damage occurs. Windows

and cladding must be specially attached in order to accommodate the relative seismic movement

of the structure without damage. Building contents can usually be adequately protected against

earthquake damage by anchorage to the floor, walls, or ceiling.

Facilities in which radioactive materials are handled are typically designed with

redundant confinement barriers between the hazardous material and the environment. Such

barriers include:

The building shell.

Ventilation system filtering and negative pressurization that inhibits outward air flow.

Storage canisters, glove boxes, tanks, or silos for storage or handling within the

building.

Release of radioactive material to the environment requires failure of two or more of

these barriers. Thus, seismic design considerations for these facilities aim to prevent collapse

and control cracks or openings (e.g., failed doors, failed infill walls) such that the building can

function as a hazardous materials confinement barrier. Seismic design considerations also

include adequate anchorage and bracing of storage cannisters, glove boxes, tanks or silos and

adequate support of ventilation ducting, filters, and fans to prevent their loss of function during

an earthquake. Long-term storage canisters are usually very rugged, and they are not particularly

vulnerable to earthquake damage.

Earthquake damage to components of a facility such as tanks, equipment,

instrumentation, and distribution systems can also cause injuries, loss of function, or loss of

confinement. Many of these items can survive strong earthquake ground shaking with adequate

anchorage or restraint. Some items, such as large vertical tanks, must be examined in more

detail to assure that there is an adequate lateral force-resisting system for seismic loads. For

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