Reflections about Nuclear Energy

by

Theo Schaub, Switzerland

May 30, 2013

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1. First contacts

My high-school graduation took place in the middle of World War II, 1942. I was fortunate to have had a very talented teacher in physics. Short after the discovery of the fissionability of the uranium atom 235 (1939) my teacher explained us the overwhelming potential of mass transformation into energy if this discovery could be governed technically. But he mentioned also the “atomic bomb”.

My technical training as a mechanical engineer ended 1947. Two years ago, in the middle of my university period, the triggering of the Hiroshima and Nagasaki nuclear bombs shocked the world. Here in Switzerland we felt relieved from the menace of Nazi terrorism but, on the other hand, we were very sorry that the nuclear challenge was first demonstrated in a destructive action. At that time I did not know that the USA had already developed reactor systems for peaceful use and that in the year 1951 the experimental fast breeder reactor EBR II had already demonstrated nuclear induced electricity generation.

2. Personal experience

My first professional engagement led in nuclear distant areas such as jet propulsion development and development for the cement industry. But in the year 1955 – the time when the first nuclear power plants, Calder Hall in Great Britain and Shippingport in the USA went into operation – a new development firm for nuclear research was founded in Switzerland. Its name: Reaktor AG. I took the chance and got an assignment there. The firm was a private society, supported by the three major Swiss firms for mechanical and electrical equipment. Five years later the owners

decided that in the long term the necessary investments would exceed their possibilities and they offered the whole institute to the government of the state. Its name was converted into EIR, in English “Swiss Federal Institute for Reactor Research”. Later on a new institute for high energy physics was added, SIN or “Swiss Institute for Nuclear Research”. In the latter one I was assigned chief mechanical engineer for the construction of the proton synchrotron and its accessories. Both institutes got together about 1975 under the name PSI, i.e. “Paul Scherrer Institute”, honoring the leading professor in physics at the “Swiss Federal High School for Technology”, ETH, during the decades 1940 to 1970.

Soon after my start in the EIR I was sent to the ISNSE, the “International School for Nuclear Science and Engineering”. The study of almost one year consisted of three parts: A basic training at the North Carolina State College in Raleigh, an informative trip across the United States with visits of uranium mines, research centers, the Idaho experimental area etc. and applied studies at Argonne National Laboratories. All this I experienced as very fruitful and fascinating. After my return to Switzerland I could help to feed the just finished research reactor (natural uranium and heavy water as a moderator) with irradiation loops.

In the year 1959 I could spend another year in the USA, this time at Oakridge, Tennessee. The study was concentrated on reactor safety. In the sequel I was member of various national and international safety panels.

My most important challenge took place from 1973 up to my retiring age (65) 1988 with the last and most powerful nuclear power plant in Switzerland, the Leibstadt boiling water

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reactor. Its design power was 930 MW. After various improvements on the nuclear, mechanical and electrical side it produces today 1250 MW. There I was as the deputy station manager responsible for the technique in general and for the safety in particular.

3. Nuclear power in Switzerland

During the decade 1960-1970 a number of very different projects and reactor concepts have been produced. Among those was a reactor, intended for heating purposes for the different university institutes of the town. Its location was close to the center of Zurich, under the buildings of the ETH. It had not exceeded the paper status. Another project was realized finally. It was intended as a prototype power reactor on the basis of natural uranium, heavy water moderation and carbon dioxide cooling. Instead of a secondary containment the whole installation was inserted into a hill of sediment stones. The electric power was about 7 MW. Due to the reduced dimensions, the fuel had to be slightly enriched. The reactor could not be operated for a long time. After a shutdown period water could penetrate into the cooling circuit. This led to corrosion of uranium sleeves, made of a magnesium alloy, which in turn hindered the full cooling capacity. A short circuit occurred and some of the fuel elements melted down and the moderator tank burst. Fortunately the shutdown installation was designed against such an event and the chain reaction stopped. No wonder that the further development of this reactor type was cut down. But the accident was not the main reason for this decision. In the mean time it had become possible to purchase enriched uranium and the nuclear industry offered turnkey installations.

In 1969 the first full size nuclear power plant, a PWR, was started. It is known as “Beznau I”, situated not far from the German border. Two years later “Beznau II” followed, but also

“Mühleberg”, a BWR situated in the region of Berne. All three power plants in the power class of 400 MW are still operating. They figure under the oldest power plants of the world.

Two more power plants have been erected afterwards, that is “Gösgen”, a German Pressurized Water Reactor in the 1000 MW class and “Leibstadt”, a General Electric/BBC Boiling Water Reactor whose power I have mentioned before.

It is not negligible to say that the public opinion and the political guide lines have been rather favorable at that time. During the years after 1960 it became evident that the country had to augment the production of electricity, as the exploitation of the hydraulic capacity approached the economical limit. The responsible member of the Federal Council argued that we did not dispose of own primary energy sources, except the hydropower and that we were already very much dependent on fossil energy for transportation and heating. So we should not increase the consumption of fossil fuel in behalf of electricity production. It would be the appropriate time to enter into the nuclear technology. It would come just in time to fill the lack. It would also help to preserve landscape, air and water.

4. Future of nuclear power in Switzerland

Similar to many countries, also in Switzerland there has been a fluctuating equilibrium between pro and contra of nuclear energy. The construction of a 6th nuclear unit in the middle of the seventies had to be abandoned due to strong local opposition, mainly from the town of Basel. However, when the Swiss citizens have been called to express their opinion on the future of nuclear power, four times they have voted for a continuation of its exploitation.

In view of the excellent operation result of the existing power plants the public opinion has risen in their favor slowly until elsewhere big

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accidents occurred. After the Chernobyl catastrophe the catchword was spread “Chernobyl is everywhere”.

Much stronger was the reaction on the Fukushima catastrophe, two years ago. The German lady chancellor decreed a few days afterwards that 7 German power plants had to be shut down immediately. The Swiss Federal Council had at that time a female majority. Women are always more critical against nuclear and radiation in general. So short after the German declaration the Swiss government declared that the country would abandon nuclear energy and replace it by renewable energy. The declaration was softened by the supplement that the shut-down should not take place immediately or at a fixed date. The operating plants would be allowed to continue as long as the safety could be guaranteed but no new plant would get permission.

It is obvious that the electricity producing societies had already started with projects to replace the existing plants. They had to, since the Beznau and Mühleberg plants approached their designed – and prolonged – life time. In addition the contracts with France for the supply of nuclear energy – at an amount of 1½ big power plant – would expire also about at the time when our own plants had to be taken off the net.

For the specialists in the energy field it is clear that the ambitious goal of the government cannot be reached in due time. Further, many organizations in the area of nature and landscape protection oppose the attempt to cover hundreds of hills with wind generators or, for instance to install solar panels on the roofs of the splendid old town of Berne.

Even the government has admitted that it would be necessary to erect a number of gas fired combined power plants during a transition period. Thus, the former prime goal to reduce carbon dioxide emission has dropped down to a very low priority. This about-face has also puzzled many inhabitants.

The first idea of the government was to settle the abandon of the nuclear technology into the constitution. Fortunately, the government is not all-mighty. The last word has the people when, as mentioned before, public initiative against laws or principles is taken. This challenge will have to be taken within the actual decade.

5. Nuclear power world wide

After a long period of stagnation the decision to extend nuclear power or to adopt it as a necessary means to increase the standard of living has been taken in a number of countries. Even in the Arabic world one seems to realize that the mineral oil will be exhausted within the next generations and projects for nuclear power are inaugurated. More than 200 nuclear power plants are in construction or in the project phase worldwide, about 80 in China.

It is my opinion that:

Exploitation of nuclear energy will increase steadily until a possibly new technology for electricity production is developed.

The symbiosis of thermal reactors and fast breeders must be established in the future.

Though severe accidents cannot be excluded, the probability of their occurrence will decrease and the overall safety level will augment since a worldwide network contributes to spread the knowledge of weak points and to eliminate them.

Nussbaumen, 30 May 2013