RRFM 2009 Transactions - European Nuclear Society

7. Electrical heater
The external heating is provided through electrical elements inside two stainless steel
cylinders and the gap between elements is filled with high thermal conductivity material
(Figure 6). The maximal power will be roughly 20 kW over a total length of about 300 mm.
This system allows heating the upward NaK before it returns and the downward NaK before
it enters into the pump core. The injected power is an important parameter to control and
adjust the operating conditions in the sample zone. Thermocouples will be placed into the
NaK and inside the heating cylinder between electrical elements.
Figure 6 : Electrical heater
8. Safety requirements and pressurized equipment rules
The safety approach of the test device must be consistent with the safety rules applied to the
reactor and to the nuclear pressurized equipment rules. In the case of CALIPSO, the major
hazard source is the NaK circulation inside the experimental device. In order to prevent
interaction between NaK and the water of the reactor primary circuit, which could damage
the core fuel or other close experimental devices, the two test device envelopes will be
classified as containment barrier and respect specific quality requirements following the
RCC-MX mechanical reference code (5) (design, materiel supply, manufacturing and
controls).
In the design phase, thermal-mechanicals calculations have been performed taking into
account the irradiation effects on mechanical properties of stainless steel tubes. Geometry of
the containment was adjusted to follow the reference code requirements in order to have
maximal stress values less than admissible criterion.
9. Conclusion
Progresses on designing the CALIPSO device have been made concerning its operating
range and its main components such as the electromagnetic pump, the electrical heater and
the heat exchanger. The overall dimensions of the tubes have been defined according to the
safety requirements and regulatory rules.
A contract towards industry is now in progress for the CALIPSO development covering the
detail engineering design study and the manufacturing of a prototype. It will be qualify in an
out-of-pile facility that will be built in 2010. The main objective will be to validate the
dimensioning and the performances of the main components of CALIPSO and the global
behaviour of the NaK loop.
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