Access Controls and Shielding from Radioactive Hazards

DOE-STD-6003-96

3. a control device that energizes a conspicuous visual or audible alarm signal so that

the individual entering the High or Very High Radiation Area and the supervisor of the

activity (e.g., in a control room) are made aware of the entry;

4. entryways that are locked when not accessed and over which positive control can be

maintained when accessed;

5. continuous direct or electronic surveillance that is capable of preventing unauthorized

entry;

6. a control device that automatically generates audible and visual alarm signals to alert

personnel in the area before use or operation of the radiation source in sufficient time

to permit evacuation of the area or activation of a secondary control device that pre-

vents use or operation of the source;

7. for Very High Radiation Areas, additional measures as necessary to prevent access to

the area when dose rates are above the lower limit for a Very High Radiation Area.

Consideration should be given, in the selection of controls, to the allowance of space for

the controls, the necessity for administrative oversight of the controls, the need for periodic

inspection of the controls, and the ease with which a control may be bypassed. No control

should be installed such that it would prevent rapid evacuation of personnel.

b. Shielding

Shielding design should be based on the appropriate design objectives given in

10 CFR 835. The choice of design, arrangement, and material for shielding should be optimized

considering the following factors at a minimum: efficacy of dose rate reduction, potential corro-

sive or galvanic effects, the advantages of homogeneity vs the advantages of layers, weight, the

need for mobility of the shield, radiation heating potential, temperature resistance, and activation

potential. Occupancy considerations should be considered, including purpose of access(es),

required frequency of access, stay times, and number of workers requiring access.

The design of concrete radiation shields should be in accordance with the requirements of

ANS 6.4. The quality factors given in 10 CFR 835 should be used for determining the dose

equivalent of the various types of radiation for dose rate calculations in conjunction with the

appropriate methodology of ANSI/ANS-6.1.1-1977; alternatively, ANSI/ANS-6.1.1-1991 may be

used, where justified, with quality factors corresponding to its methodology (e.g., as given in

NCRP 116).

The shielding design for fusion facilities should consider the anticipated high-energy neu-

tron spectrum; appropriate high-density shielding should be provided as necessary for these

neutrons and made compatible with shielding for neutrons of lower energies and for gammas.

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