Critical Reflections about Doel3 & Tihange2

Integrity reactor vessels Doel 3 and Tihange 2

Page: 2

Preface

For an engineer who has followed the news about the reactors of Doel 3 and Tihange 2, it was quite amazing and against common engineering sense that these two reactors are put in service again after three years of research, whereby more than 13000 flaws in the reactor vessel shells have been re- ported. This forms the cause to search for relevant information. A number of reports concerning the reactor vessels of Doel 3 and Tihange 2 are present at the FANC website http://www.fanc.fgov. be/nl/page/dossier-pressure-vessel-doel-3-tihange-2/1488.aspx?LG=2 . Unfortu- nately, these reports are difficult to read, they are tedious, the information is very fragmented and spread out over a large number of different reports. In order to understand how such an investi- gation is carried out, it is recommended to read a report about another case of Structural Integrity Associates Inc. [ 1 ] . This 82 page report deals with a crack of a weld inside a reactor vessel, it ex- plains clearly the course of the investigation, provides the data of the materials and the load cycles, cites where necessary the approach and the data from the "ASME Boiler and Vessel Code", describes the calculations and presents the results in such a way that technical skilled people outside the nu- clear sector can understand these calculations. This is not possible with the material provided in these reports on the FANC website. To do calculations, data from the report of Structural Integrity Associates Inc. [ 1 ] are used, as these data lack in the reports provided by FANC. The findings will be illuminated in this note. First, the construction of the pressurized water reactor (PWR) will be illuminated such as it is presented in the reports of Electrabel. Then, some principles of fracture mechanics will be explained. Next, the most important issues from the Electrabel reports will be illuminated. This will be done at hand of the reports itself, the reader must have these reports at his disposal to follow the explanations, such that a biased viewpoint will be avoided. Then, the critical attention points will be formulated. The consulted sources will be cited by their internet addresses in the bibliography where possible, such that the reader is capable to find them quickly. The authors are totally independent from any organisation or political party and want to keep it that way. The authors believe that nuclear energy will be indispensable in a low–carbon economy. It will not be possible to fully replace the current production of electricity by wind turbines and solar cells [ 2 ] . These energy sources consume too much space in our highly populated areas and varies too strong with the weather conditions. Nuclear energy can be safely used on the condition that normal engineering rules will be followed with reactors which follow the state of the art and that exploitants and government accept that every technical installation has a finite lifetime and needs to be replaced by new ones which comply with the actual state of the art. An accident in the primary circuit of a nuclear reactor, even when the consequences remain inside the nuclear plant itself, will make nuclear energy impossible in the future.

R.Boonen & J.Peirs

May 18, 2017