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HFEB SER Input on Proposed Change to Grand Gulf Technical Specification Regarding Control Room High Temperature Limit Position Reliable human performance is degraded by extreme environmental conditions.
NUREG-0700 establishes a set of environmental confort guidelines for control i
rooms to minimize the potential for operator error during long-term operations.
It provides normal comfort ranges for environmental parameters and addresses extreme conditions only to a limited extent.
In order to evaluate human performance in extreme environmental conditions the staff must l
rely on studies supported by the Department of Defense (See reference).
Discussion By letter dated September 9,1983, Mississippi Power & Light Company has proposed a chan Station to, (1)ge in the technical specifications for Grand Gulf Nuclear delete the " Equipment Not Operating" column from the Area Temperature Monitoring Table 3.7.8-1, (2) delete the column heading
" Equipment Operating" from Table 3.7.8-1, and (3) change the 77'F limiting temperature for the control room to 90'F.
The HFEB agrees with the proposed changes and justification by the Applicant to delete the " Equipment Not Operating" column and the column heading
" Equipment Operating" from Table 3.7.8-1.
With regard to the proposed change in the limiting temperature for the control room, the staff agrees that the 77'F dry bulb temperature limit of NUREG-0700 was established as a comfort limit for long-term operation to minimize the potential for operator error due to fatigue or discomfort. This temperature limit also assumes a relative humidity below 60%.
Studies supported by the Department of Defense indicate that, for short periods of time (up to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />), human operators can be expected to perform reliably in an " effective temperature" environment up to 85'F, wearing i
conventional Itght clothing, doing light, manual, seated work. Effective i
temperature takes into account dry bulb temperature, relative humidity, and l
air flow.
In the control room environment, an 85'F effective temperature can j
be composed of the following conditions:
Dry Bulb Temperature Relatlvf umidity Air Flow H
'F
'C ft/ min 85 29.5 100 0-30 90 32.2 72 0-30 95 35.0 48 0-30 70 0505 05072gs s.
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V 2-Since the technical specification is considering only dry bulb temperature and the staff cannot be assured that relative humidity will be below 72%, nor that it will not approach 100%, it is the staff position that the limiting condition for operation in the control room relative to high dry bulb temperature should be 85'F. This value is also consistent with the maximum I
effective temperature allowed in the Grand Gulf remote shutdown panel area i
when it is manned in any mode of operation.
i Conclusion
,l The staff agrees with the proposed deletion of the " Equipment Not Operating" column and " Equipment Operating" heading from Table 3.7.8-1 of the Grand Gulf technical specifications.
1 The staff does not agree with the proposed change of the control room eight-hour dry bulb temperature limit from 77'F to 90*F, but does support a change in this limit to 85'F dry bulb temperature.
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References:
>i MIL-STD-1472C, Human Engineering Design Criteria for Military Systems, i
Equipment and Facilities, May 2, 1981.
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l MIL-HDBK-759A (Proposed), Human Factors Engineering Design for Army Materiel, l
January 7,1981.
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