Other Natural Phenomena

DOE-STD-1128-98

Guide of Good Practices for Occupational Radiological Protection in Plutonium Facilities

C.3.4 Other Natural Phenomena

Design loads and considerations for other natural phenomena should provide a conservative

margin of safety that is greater than the maximum historical levels recorded for the site.

Protection against flooding should be based on no less than the probable maximum flood

(PMFL) for the area as defined by the Corps of Engineers. The possibility of seismically

induced damage or failure of upstream dams should be taken into account in assessing the

nature of the flood protection that is required for the facility. If the facility is in a location

that may be subject to ashfall from volcanic action, consideration should be given to the

effects of ashfall on ventilation and electrical systems.

C.3.5 Explosion, Internal Pressurization, Criticality, and Other Causes of Design-Basis

Accidents

Analyses should be made to determine the probable consequences of design-basis accidents

(DBAs), and critical areas and critical items should be designed to withstand DBAs. The

portion of the ventilation system that is an integral part of the critical areas should be

designed to withstand DBAs so that it will remain intact and continue to act as a

confinement system. Building ventilation is an important part of confinement barriers and,

in some cases, air flow may become the only barrier.

C.4 BUILDING LAYOUT

Building layout is extremely important in the operation of a plutonium facility. Improper or poor

layout can lead to operational difficulties and in some instances can contribute to the development

of abnormal situations that may affect personnel safety, result in unnecessary exposure to the

worker and the public, and/or increase the cost of operating the facility. Normally, three areas are

involved in the overall building layout. These areas may be described as:

-- The process area, where plutonium or other radioactive or hazardous materials are used, handled,

or stored;

-- the controlled area, which is normally free of radioactive material but could potentially become

contaminated; and

-- the uncontrolled area, which includes all areas where no radioactive materials are permitted and

radiological controls normally are not necessary (e.g., offices and lunchrooms).

The terms controlled area and uncontrolled area defined above refer to radiologically controlled

and uncontrolled areas. These terms are not to be confused with the formal definitions of controlled

and uncontrolled areas related to safeguards and security concerns.

C.4.1 Objectives

The following objectives should be achieved in the design layout of the facility:

-- Planned radiation exposures to personnel shall be within the prescribed limits of 10 CFR

835 Occupational Radiation Protection (DOE, 1998a). 10 CFR 835.1002 contains

requirements for ALARA design objectives for the design of new facilities or the

modification of old facilities.

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