WRITTEN QUESTION E-2892/02

by Erik Meijer (GUE/NGL) to the Commission

(14 October 2002)

Subject: The danger of ruptures in cooling-water pipes at the High Flux Reactor in Petten, the Netherlands, and failure to take measures to avert the danger

1. Is the Commission aware of reports in various Dutch media that the primary inlet pipes to the cooling-water system at the High Flux Reactor in Petten, the Netherlands, for

which the Commission holds the licence, are under heavy stress and could break, as a result of which the reactor core would no longer receive cooling water and would melt, causing radioactive contamination of the surrounding area?

2. Is the Commission aware that the danger of such a rupture is increased by drilling for natural gas in the vicinity, which could cause subsidence under the reactor complex, which is built on sand from dunes?

3. Can the Commission confirm that attention was drawn to the risk involved in a pipe rupture as long ago as 1985, that it would be relatively simple to avert the risk, and that in 1994 a technical alteration was proposed in order to contain any rupture, but that this proposal has still not been implemented because of the controversial argument that the pipes could probably withstand an earthquake?

4. Does the Commission know why, unlike the inlet pipes, the primary cooling-water outlet pipes are equipped with a facility to contain any emissions resulting from a possible rupture in them?

5. Is the Commission aware that the primary cooling-water system was originally designed for a 20 MW reactor with a cooling-water flow of 2 750 m3 per hour, but that since 1970 the reactor has been operated at a rating of 45 MW and with a cooling-water flow of 4 150 m3 per hour? Are the design specifications of the primary cooling-water system sufficient to cope with this substantial increase in the cooling-water flow and the resultant resonances?

6. Was an examination of the above problem included in the assessment which resulted from the visit to the reactor by the International Atomic Energy Agency (IAEA) from 3 to 8 March 2002 and the recommendations drawn up in that context for improving the safety system, and the thorough review of the licence mentioned there? Have these recommendations since been implemented?

7. How can the fear of accidents involving the cooling-water system be permanently eliminated, and what will the Commission do to help achieve this?

Answer given by Mr Busquin on behalf of the Commission

(3 December 2002)

1. The Commission is aware of various media reports regarding accidental scenarios affecting the coolant system of the high flux reactor (HFR) and their possible consequences.

2. The Commission is aware of the subsidence of the reactor pond. This concerns a difference in height of one centimeter (cm) all along the pond, which has been known for 30 years and has not increased since. In addition, the reactor design does allow for subsidence.

3. Taking benefit of the current ten years safety re-evaluation, which started in 2001, the Commission has agreed with the safety authorities that, the safety analysis would be complemented by the analysis of a large break loss of coolant accident scenario. This analysis will be completed and submitted to the safety authorities by mid-2003. Such scenarios had already been internally evaluated by the staff of HFR operating company in the mid-eighties and early nineties and were described as the Veldman scenario. These scenarios are normally considered as a design basis accident for pressurised water power reactor, but had not been included in the design basis of the HFR operating at much lower pressure and temperature.

4. The emergency systems presently installed on the HFR reactor differ in the inlet and outlet piping as they take into account the geometry of the primary circuit and the location of the primary pump.

5. When the power of the HFR reactor was increased from 20 megawatt (Mw) to 45 Mw, it was implemented in full agreement with the safety authorities and the operating licence of the HFR was modified in 1970 to this end.

6. The problem referred to in the above questions was not covered in the evaluation made by the International Atomic Energy Agency (IAEA) from 3 March 2002 through 8 March 2002, that addressed the reactor safety procedures and staff training in this respect. The IAEA recommendations do not address the improvement of the safety system itself. The implementation of IAEA recommendations is progressing according to plan and in close contact with the safety authorities. The ten year revision of the licence that do include the re-assessment of the coolant leak scenarios, is not related to the IAEA evaluation and had already been started more than a year prior to the IAEA evaluation.

7. The safety evaluation currently under way will be submitted to the competent safety authorities and conclusions will be drawn. In addition, open consultations are held with the regional and local authorities.