RRFM 2009 Transactions - European Nuclear Society

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The benefits of this configuration outweigh the cost increase for the submerged pump:
• No penetration of piping through the pool walls is used
• No room occupation around the pool (space availability is limited there)
• No need to install radiation shielding (against N 7 and possible fission products)
• No additional risk for BR2 in case of rupture of the piping
• Improved safety, when compared to non-submerged solution:
• The ΔP provided by BR2 primary circulation remains available in case of failure of
the booster pump. So reduced cooling remains available to remove the decay heat of
the tested fuel.
• EVITA being submerged in BR2 pool, a breach in EVITA piping will not lead to
the fuel dry-out.
• EVITA uses mostly BR2's own protection systems.
The pressure profile in EVITA is shown on fig.3 below. The diagram starts at 12,7 bar (static
pressure of BR2 plus ΔP delivered by BR2 primary pumps, which is the pressure in the upper
plenum of BR2) and ends at 9,3 bar, the pressure in the lower plenum of BR2.
17
Fig.3: Pressure profile in EVITA
16
Dynamic pressure [bar]
15
14
13
12
11
BR2 upper plenum
Flowmeter
Pump
Fuel
.
1
9
BR2 lower plenum
1 11 21 31 41 51 61 71 81 91 101
Position along the circuit (calculation points)
If the EVITA booster pump fails, the ΔP delivered by BR2 primary pumps is still more than
sufficient to remove the decay heat of the fuel element, and vice versa. If both pumps fail,
which could happen in case of loss of external electrical power, a batteries powered UPS group
will deliver current for one hour, at which time the residual heat can be removed by natural
convection.
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