All systems
General indication of physical layout in the plant, indicating segregation of redundancies
Indications of any support function dependencies which do not take immediate effect (eg can a HPI pump operate for a short time without component cooling or room cooling?) ( In default of information, operation without supports would be assumed impossible.)
Any lack of qualification for safety duties in severe accidents (eg is the main feed system qualified for safety related AFW provision ? Are the fan coolers qualified for post-core melt containment duty ? )
An example of the type of information required is provided in Appendix 1, where an adequate set of information on the Sizewell B high pressure inject- ion system is listed.
Additional details
Information on additional plant specific or generic matters which the prospective vendors consider to be relevant will be taken into account. The types of matter which might be addressed are :
Ultimate safety procedures (U-procedures ).
Feed and bleed cooling possibilities for the primary circuit
Recovery from station blackout situations
Special systems, not typical of PWRS as a whole (eg a local hydro plant as backup power supply found on a few PWR sites such as the Swiss Beznau site, but not typical )
Maintenance provisions
It is not expected to take account of specific maintenance provisions for every system, but to assume normal international standards. However, the contribution of the primary circuit/low pressure circuits interface to risk can be strongly influenced by the maintenance and checking of the interfaces and specific information on intentions regarding these systems would be useful.
In default of information
Since it is not likely that fully adequate information will be provided on all aspects mentioned above, SRD would propose to make use of its knowledge of normal international practice to create default information where the specific information is lacking. The assessment will then be based on the default information, and subject to revision if different specific information is substituted. Since the Daya Bay plant is expected to be based on a known and common type of Framatome plant ( PWR 900 twin ), the default and specific information should not be grossly disparate,