The recently announced memorandum of understanding between PBMR (Pty) Ltd of South Africa and Chinergy of Beijing on collaboration in the development of high temperature gas-cooled reactor technology makes very good sense, although the specifics of what is planned are as yet unclear. The partners say, a little vaguely, that “the main objective of the agreement is to pursue the potential developments which could be realised through co-operation for the high temperature reactor demonstration projects in China and South Africa, as well as for the commercialisation of these reactor systems thereafter.” Make of that what you will.

Although a court ruling in favour of environmental activist group Earthlife Africa has delayed completion of the Environmental Impact Assessment process for Eskom’s proposed 400 MWt (approx.) demonstration Pebble Bed Modular Reactor project – overturning an earlier decision in favour – PBMR (Pty) Ltd says this will not “necessarily impact upon the overall construction schedule.” It is still aiming to start building its demonstration reactor at Eskom’s Koeberg site and a fuel plant at Pelindaba in 2007, to be completed in 2010.

For Eskom, instigator of the South African PBMR effort, China has much to contribute, not least of which is an operating high temperature reactor, albeit of relatively limited size.

Also, judging by what we know of the 11th Five Year Plan (which will run from 2006) and the 2020 long term plan, the Chinese government is increasingly favourably disposed to expansion of nuclear energy in general and large PWRs (see p 21) and high temperature reactors in particular, with talk of the need to “step up the development” of nuclear power and to “popularise (sic) high temperature gas-cooled reactor technology.”

In addition China’s high temperature gas cooled reactor programme seems to be moving forward, with a schedule strikingly similar to South Africa’s PBMR demonstration project. In China plans are firming up for a 195 MWe/458 MWt high temperature reactor demonstration plant, the HTR-PM, to start construction in 2007, with the aim of achieving first criticality in 2010 (as described in the March 2005 issue of Nuclear Engineering International). A likely site is Wuhei on the coast of Shandong Province and project partners will include generating company Huaneng (50%), China Nuclear Engineering and Construction Corp (35%), Beijing’s Tsinghua University (5%), while the remaining 10% is to be offered to other investors.

Interestingly, PBMR is also seeking investors for its project. So might the China/South Africa collaboration extend to some form of cross participation or shareholding in each other’s demo projects? This remains to be seen.

Both projects pose technological risks, which, of course, it is the role of a demonstration facility to address. The helium cooled South African PBMR will employ a direct cycle gas turbine, which is a major innovation. There is a plan to test the HTR-10, also helium cooled, with a direct cycle turbine next year, but the HTR-PM will adopt the more familiar indirect approach using the helium as the heat source for a conventional steam cycle (as in the current HTR-10 configuration). Nevertheless, the HTR-PM represents a very ambitious scaling up from the HTR-10 cogenerating test facility, which has a thermal capacity of a mere 10 MWt (as the name would suggest) and provides a modest 2.5 MW of electrical generating capacity in addition to heat.

One thing very much in its favour however is that the HTR-10, located at INET (Institute of Nuclear and New Energy Technology), part of Tsinghua University, is actually up and running, having achieved first criticality in 2000 and reaching full power with grid connection in January 2003. Indeed, it is the world’s only operating pebble bed reactor, and one of only two operable high temperature reactors currently in existence, the other being Japan’s 30 MWt High Temperature Test Reactor.

With the prospect of the Chinese and South African HTGR programmes combining forces under the new MOU, a further logical step in HTGR development might be to bring Japan on board. In fact Japanese company Mitsubishi Heavy Industries is already very much involved in the South African PBMR effort as a key contractor. One small snag when it comes to further Japanese involvement is that Japan’s current HTGR technology employs block type fuel as opposed to the German developed pebble bed concept. But in the light of the tremendous advantages that would flow from collaboration with the two other HTGR-developing countries perhaps the Japanese should explore the possibility of a future switch to pebble bed technology, which seems to offer major inherent benefits.

What a waste

Alleged failure to properly address radioactive waste management issues is one of the main reasons why the earlier approval of the Environmental Impact Assessment for the South African PBMR has been set aside.

The PBMR plan is to store all the spent fuel produced by the reactor over its 40 year life in dry storage tanks within the reactor building. It will then be kept on site for a further 40 years before being sent to a final repository. PBMR proponents argue that the pebble fuel is much easier to store long term than conventional fuel rods “because the silicon carbide coating around the fuel particles will keep the radioactive decay products isolated for approximately a million years.”

It would be great shame if the project were to founder on spent fuel management issues, but coming up with convincing arguments on waste disposal has certainly proved one of the nuclear industry’s weak spots over the years.

Some countries, notably Finland and Sweden, have made great progress in this area, whereas others, for example the UK, are in disarray. A recent damning report by the UK House of Lords Science and Technology Committee expressed dismay at delays in formulating a coherent policy and astonishment that a new advisory body, the Committee on Radioactive Waste Management (CoRWM), had been instructed to start from “a blank sheet of paper”, despite “an overwhelming international scientific consensus that underground disposal or storage is a safe long-term solution.” The Committee thought that CoRWM should stop wasting time considering options that have been discarded by the rest of the international community (such as blasting waste into space) and it was also concerned that CoRWM appeared to lack the technical expertise to assess the options. Speaking in the House of Lords the Committee’s chairman Lord Oxburgh said they had been told that the composition of CoRWM was designed to be representative of a “broad spectrum of opinion”, but he questioned whether the minister responsible “would be happy to fly in an aircraft for which the engine design had been chosen by a committee ‘representative of a broad spectrum of opinion’.”

It is to be hoped that radioactive waste disposal policy is in better shape in South Africa otherwise getting final approval for the PBMR Environmental Impact Assessment could be somewhat more difficult than the project’s proponents seem to think it is going to be.