Structure - doe-std-1128-98

DOE-STD-1128-98

Valve seals and gaskets should be resistant to radiation damage.

Straight-through valves generally should be used to simplify

maintenance and minimize particle traps.

Valves should be designed to operate in the stem-up orientation, which

would limit potential leakage when the pipe is unpressurized. Valves and

flanges should be located to minimize the consequences of

Generally, process solutions should have primary and secondary

confinement. However, in rare instances where process solutions are

allowed to flow outside of confinement, they should flow only by gravity

and the pressure head should be limited to an equivalent of about 10 feet

of water.

The corrosion resistance of the primary block valve and/or check valve

and all associated piping in the in-cell and/or contaminated areas should

be equivalent.

The use of pumps in contaminated piping systems should be avoided to

reduce potential contamination problems that result from pressurization

and to reduce the maintenance requirements associated with pumping.

The use of gravity flow, jets, vacuum, or airlifts is a suitable alternative.

Vacuum transfers are preferred. If jets or airlift transfers are used, an

adequate waste-air cleanup system should be provided.

C.4.3.2

Structure

Floors should be designed in accordance with code requirements

considering the maximum loads anticipated.

C.4.3.3

Storage

In-process storage should not be permitted; however, temporary storage

of the product in the process area until it can be taken to an appropriate

storage area should be permitted.

Storage facilities in the process areas should be designed to prevent the

exposure of operating personnel and to meet the requirements for

security and safeguards.

C.4.3.4

Shielding

Provisions should be made to accommodate the shielding of all items in

the process area. All structures (e.g., floors, walls, and glove boxes) may

require additional shielding during the lifetime of the facility because of

increased throughput or higher radiation levels of the material being

processed.

C-14