Design and development work for the Argentinean project called CAREM is continuing The project is ten years old and the initial design power level was 15 MWe The current work is on a 25 MWe reactor, with thought being given to a 100 MWe reactor. Engineering for the 25 MWe plant is scheduled for completion by the end of 1996. Financial, political and siting decisions are expected to be made in 1996, which if favorable, will lead to construction in 1997. Experimental work is under way in a high pressure loop to study critical heat flux (CHF) and dynamic response, and to make a comprehensive study of the reactor physics of the core in the RA-8 critical facility Development and testing is being carried out on the core internals, control rod drives & position indicators and the reactor protection system, especially the trip system

1.2. China

Loss-of-coolant experiments are being carried out for the Chinese nuclear heating reactor (NHR200). A test loop has been in operation since 1989, and allows tests on the three possible positions for a break to occur, (i) pipes on the upper plenum, (ii) steam generator pipe break and (iii) boron injection pipe below the vessel water level. Experiments have shown good agreement with the results of calculations on the influence of the break position on RPV water level, on discharge quality and hence on the depressurization rate. Depressurization is quite slow (thousands of seconds), due to the small size of pipe connections.

China is carrying out a study on the choice of a reactor system for a co­generation plant. The study is based on a 2×450 MWt plant and hinges on the configuration of the intermediate loop A comparison is being made between two alternatives; (i) steam generator in the RPV supplying steam to the turbine and an external steam water heat exchanger, and (ii) a system with an in-reactor high pressure water heater which provides hot water to generate steam in an inverted U-tube steam generator The steam passes to the turbine and back-pressure steam provides the heating load.

The second alternative allows a lower primary pressure and hence a saving in cost The possibility of radioactive leakage into the tertiary circuit is reduced due to the high reliability of water-water heat exchangers and by having a secondary pressure higher than the primary pressure. The overall efficiency loss from having a 10 MPa primary is offset by the higher efficiency of the second heat exchanger which is a steam generator rather than a low efficiency steam/steam heat exchanger

З 3 Indonesia

Indonesia is presently giving serious consideration to the introduction of nuclear power Strategic planning in Indonesia also envisages the utilization of an integral reactor design for the supply of heat and electricity to many of its islands. The perspective plan is to Install 12,000 MWe of nuclear power by 2019, of which the majority will be based on large reactors of existing designs. There is, however, a potential market for a 30 MWe design, suitable for several small islands in Indonesia resulting from the high cost of transportation of fossil fuel

3 4 Italy

The reactor continuing to be developed in Italy is named Inherently Safe Immersed System (ISIS). This reactor has components which are passive at category "B" in the IAEA definition which means that they need no valve movements or logic circuits for system initiation. The reactor uses some of the concepts used in the "PIUS" design but has a very small heated primary inventory with density locks to give access to highly pressurized cold water in the event of a reactor malfunction. Data on safety analysis shows the very high level of safety that can be achieved The problems of deployment are now economic rather than safety related The system could be competitive in a co-generation mode, perhaps with a pressure reduction to decrease the mass of steel needed. Further work on tackling the economic competitiveness aspects is under way.