Cooling Systems - Continued

DOE-STD-6003-96

Additionally, the pressure load range should include temperature-induced pressures,

hydrostatic test pressures, and any credible pressure augmentation resulting from

small leaks between two coupled cooling systems.

Cooling systems that are safety-class should have design, fabrication, inspection, and

testing in accordance with a recognized safety-class code such as ASME 1992. The

specific codes and criteria selected should be commensurate with the level of safety

required and should have a technical justification. Table 6.1 gives suggested design

codes for the cooling system. Where ASME design is not feasible, such as in the case

of unique materials or designs, the alternate codes listed in Table 6.1 may be used.

Piping and equipment supports should be designed to ANSI/AISC N690 (ANSI 1984)

or equivalent. Cooling system components that are safety-significant should have

design, fabrication, inspection, and testing in accordance with a recognized national

consensus code such as ANSI/ASME B31.3 (ANSI 1993a).

b. An analysis of cooling system deflections over the full range of temperatures, vacu-

ums, and pressures should confirm no interferences or loss of pressure boundary

integrity.

c. The cooling system boundary materials and design should provide sufficient margin to

ensure that, when stressed, the boundary behaves in a nonbrittle manner with a very

low probability of rapidly propagating fracture. Coolant should be compatible with

structural materials that it may contact during normal operation and off-normal events

throughout the range of anticipated physical parameters. Table 6.1 lists the materials

requirements. Alternative codes and standards may be used with appropriate

d. Cooling system design should provide for instrumentation to monitor safety-related

variables and controls to maintain the variables within design limits (see also

Section 6.4.1). The cooling system design should provide for instruments to detect

and measure abnormal leakage and controls to isolate and mitigate the leak. To the

extent practical, the primary mode of actuation of safety functions should be automatic

and should be initiated by detection and control channels of suitable diversity and

redundancy.

e. Design should provide means to collect spilled coolant to prevent damage to safety-

class SSCs and to limit contamination and environmental releases.

Design should provide makeup coolant for breaks, leaks, or draining required for

maintenance activities. The coolant makeup rate should be sufficient to maintain the

heat removal and rejection capacity to prevent or limit damage of safety-class SSCs

while allowing only negligible materials reactions with the coolant.

g. For shutdown conditions, the cooling system design should incorporate passive fea-

tures to the extent practical for heat removal, transfer, and rejection functions. The

design objective should be to provide adequate cooling of all safety-class SSCs

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