1. Previous Minutes

2. Substation Planning

Based on the heat dissipation figures provided by Anne, Jukka had prepared some options for the air conditioning arrangements for the different substation rooms.

The 18kV cell needs no special arrangments as the load is only 1.5kW.
The 30kW heat load in the saferoom requires a dedicated air conditioning unit. This can be located in the S-430 storage area. Some civil engineering work would be required to allow cold air injection below the false floor. Extraction would be via a simple grille at ceiling level. There would be no requirement for ductwork inside the room.
The situation for the LV room is less clear. The heat load of 10kW is not high enough that active cooling is certainly required, nor low enough that passive cooling is clearly adequate. If active cooling is required, the extra load could be supported by making a simple modification to the unit cooling the existing LV area. There was, however, some concern about how the required ductwork could be accomodated. More detailed information on the exact load is needed to decide between active or passive cooling.

Jukka pointed out that keeping the ductwork for the LV room would, if they were equipped with dampers, allow these to be used for smoke extraction (with insulation added and assuming correct rating for fans, to be checked). However, adequate smoke extraction could also be ensured by pushing air in from the corridor and having a chimney—although any chimney would have to be sited carefully to avoid blocking access to the barn doors.
It was agreed that more coordination work was required to understand the possible layouts for piping, ductwork and cable trays across the S-206 corridor. The cost implications must also be understood—any relocation of the pipe from the steam humidifiers is likely to be problematic.

There was a long discussion on how cables could be rooted from the transformers to the saferoom and the LV room. It was finally agreed that

The 18kV room should be made large enough (5.8m) for the 4MW solution. In addition to “future proofing” this area, it provides extra space for cable trays—only 3-4 extra 18kV units would be required for the 4MW solution.
Cables from the “physics” transformers will be routed down into the 18kV room and then underfloor into the LV room.
Cables from the “general services” transformers can be routed into the saferoom either via the 18kV room or via a small extension on the Salève end of the bunker.
Routing the 400V cables via the 18kV room was not seen as problematic since a fire in this area would anyway lead to a cut in power.

The 18kV cables to the transformers have to come from the galerie technique running between B513 and B31. Two options were discussed for routing these cables:

boring small tube horizontally under B513. This was considered the best solution, but there were some concerns on the feasibility and the cost.
Routing the cables up into the S-203 corridor and then at ceiling level. It was felt that TIS would have concerns for both general safety and the (non-)separation of services.

Cables will also need to be routed between the LV room and the current UPS room. More information is needed on the size of these cables in order to understand the possibilities.
In many cases, a caniveau under the S-206 corridor would ease routing problems, but this has cost implications. It was pointed out that it may be better to have a caniveau now to allow the installation of any ducting that might be required for a later expansion. This could be done, but the costs need to be understood.

Jukka presented options for upgrading the overall air conditioning installation in B513 to support equipment loads of

Costs and an installation schedule are needed for the 2MW solution and for a later upgrade to the full solution. Information on the power demands of the 4MW solution should also be provided in order to understand the impact on the substation—can the space requirements be satisfied now?