International Topical Meeting on Nuclear Research Applications and Utilization of Accelerators

4-8 May 2009, Vienna

SM/ADS-04

The XT-ADS Core Design

G.  Van den Eynde

SCK·CEN, Boeretang, Mol, Belgium

Corresponding Author: gvdeynde@sckcen.be

The XT–ADS core has to be able to fulfill several objectives. First of all, the XT–ADS machineshould be a relevant prototype for an industrial ADS. This means that the power of the core should be sufficiently high in order to be representative. Second, the XT–ADS machine is foreseent to be an irradiation facility for EFIT, the large scalle industrial transmuter under design in the same FP6 IP–EUROTRANS project. This require that XT–ADS can reproduce irradiation conditions which are similar to the operating conditions for EFIT. For example, the ratio of damage in structural material and burn-up in the fuel is such a parameter that is important when we want to use XT–ADS as the irradiation facility that hosts the EFIT fuel qualification programme. In order to accommodate these programmes, and of course also other irradiation programmes, 8 positions in the XT–ADS core are kept free. These positions also have a penetration through the reactor lid which allows the positions to have in-pile loop types of experiments and/or extensively monitored experiments.

The constraints in which the design of the core of XT–ADS is done are quite strict. The basic
idea is to use existing technology as much as possible. Also, the design did not start from scratch: SCK·CEN offered the preliminary design of MYRRHA Draft 2 as a starting point for the XT–ADS machine.

Some major design options for XT–ADS are the fuel, the choice of coolant and inlet/outlet temperatures and the core geometry. The fuel in the core is MOX (albeit with a high plutonium enrichment) and not an innovative minor actinide fuel. The coolant is lead-bismuth eutectic. This allows us to lower the working temperatures compared to the lead cooled EFIT and as a consequence the requirements on the structural materials are not that high (corrosion, erosion, . . .). The damage caused by neutron irradiation (dpa) on some components was also a driving force behind some significant changes in the core compared to the MYRRHA core.

This paper will give an overview of the current state of the design of the XT–ADS core, motivate how we got there from the initial MYRRHA core and present a look at the future.