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International Youth Nuclear Congress Youth Future Nuclear Chernobyl Accident, 25th Anniversary. IYNC as a global network of young professionals, researchers, scholars and students has collected Young Generation Network experiences with regards to Chernobyl and has prepared the following report in order to show several technical visit to Chernobyl Nuclear Power Plant:


Chernobyl visit by Dutch and Belgium Young Generation ..........................................................2


A visit to Chernobyl by Spanish Young Generation Network (J贸venes Nucleares) .....................5

IYNC Network: Chernobyl 25th Aniversary

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“It is almost 25 years ago that in Chernobyl, Ukraine, nuclear reactor No. 4 exploded and the worst nuclear disaster in history happened. A disaster that has affected the image of nuclear energy extremely, but also showed that safety should be above all in the nuclear industry” Thus, the announcement of the Dutch Young Generation (DYG) in April last year. They organized together with the Belgian sister organization BNS-YG an excursion to Chernobyl. 10 Dutch and 10 Belgium YG members departed to Kiev on October 7. From there we should visit world's most notorious nuclear power plant ourselves. The excursion takes place on October 8. By bus we entered the 'exclusion zone', a circle with a radius of 30 km around reactor 4, where no settlement is allowed. The checkpoint at the border of this zone is about 100 km north of Kiev. Forbidden to smile The ride to the zone is dominated by vast fields and pine forests. Ukraine is the largest country in Europe and is known as "granary". Our guide Dmitry is acute in action as the bus enters the border of the exclusion zone. Passports ready, and one by one through a turnstile which gives access to the zone. A military checks each passport with the exact number on the list submitted in advance. It is expressly forbidden to make photos of the soldiers manning the checkpoint, and it’s also advised not to smile at them. It is clear that you cannot just access this area. Uninhabited but not abandoned The bus takes us to Chernobyl town, located 18 km from the NPP. 16,000 people used to live here. The residents are gone, but the city has not completely abandoned. More than 3800 people staying in the city to protect and maintain the nuclear power plant. They also work on the new sarcophagus which will be placed around the exploded unit. One of the people who works here is our guide. He tells us the work is done in teams: employees may stay up to fifteen consecutive days in the exclusion zone, then they should stay 15 days outside the zone. This is to minimize the possible harmful effects of radiation. The building site of the new sarcophagus is 200 m from reactor 4. The colossus will be 150 m wide, over 250 meters long and 100 meters high and takes the shape of an arch. When this arch is ready, it slides over the current construction. Novarka, “new arch” is the name of the company in charge of the design and construction. We get off at a government building. We need to sign a declaration that protect the Ukrainian government from any damages that we could suffer as a result of our visit. It’s part of the procedure. After this formality we go to the NPP. We pass two checkpoints, 10 and 5 km from the plant. Control Room of Unit 1 After another passport check at the power plant itself, we get white coats and caps and take a look into the control room of Reactor 1. Chernobyl consisted in April 1986 of four working reactors and two reactors under construction. Next to these plants there were plans for a further six new reactors.

IYNC Network: Chernobyl 25th Aniversary

International Youth Nuclear Congress Youth Future Nuclear Reactor 1 was in operation since 1968 and shut down in 1996. In the control room, they still keep control of the reactor vessel. Then it's time to look at reactor No. 4. The bus stops at the memorial set up for the victims of the disaster. Approximately 800 meters further down the reactor. We enter the visitor centre which provides us a panoramic view of the reactor. Distance is at most 500 meters.

The accident in reactor 4 On 26 April 1986 at 01.23 hours four reactor achieved a capacity of 30 gig watts, as much as ten times its normal capacity of three gig watts. The fuel rods melted, and the steam pressure rose and caused a steam explosion, the 2000 ton roof of the reactor was blown away. The incoming air ignite the hot graphite rods. The radioactive graphite also landed on top of the building, which was eliminated by 90,000 salvage workers (liquidators) from across the former Soviet Union. Many of them were conscripts. They were only a few minutes picking up the pieces before returning to a safer distance from the plant. This we saw in an impressive black and white movie, in the Chernobyl Museum. After the fire was extinguished and the big chunks of radioactive material had been thrown back in the core-crater, Reactor 4 was encased in a concrete sarcophagus, which was finished in November 1986. This sarcophagus holds the bulk of radiation and prevent further spread of radioactive materials for example by wind. After the disaster, the remaining three reactors were put into operation again. The construction of units 5 and 6 was discontinued in 1989. On Friday, December 15, 2000 the last working reactor, No. 3 stopped and closed the Chernobyl power plant for good.

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International Youth Nuclear Congress Youth Future Nuclear The abandoned city Our next stop is the town of Pripyat. 50,000 people once lived here. It was a new town, built in 1970 specifically for the employees of the NPP. The town is 2 km away from the plant. We climb, watched by two soldiers, to the eighth floor of an apartment building in the centre. From the balcony of a luxury penthouse, we observe reactor 4.

It's a sunny fall day. Brought by the wheeze of the dosimeters in the background, we take a walk through the city. On the square stands the abandoned carnival in honour of the 1-May celebration. The image of the Falkirk Wheel, which has come across several articles and documentaries during our preparation for the trip. Precisely because of this it is very impressive to see it in real life.

Radiation Levels The moss on the square contains many radioactive materials. "Don’t put your dosimeter on it" warns our guide, "then he hits a tilt." Just above the moss gave the dosimeter about 16 microsievert per hour (µSv/hr) At the edge of the square is a piece of land disturbed by wild pigs which now live in the city. Also there the radiometer gives a higher dose rate. At the Chernobyl monument a few hundred meters from the reactor, we had measured up to 8 µSv/hr. We leave Pripyat and return to the checkpoint at the border of the exclusion zone. Along the side of the road here and there a simple white sign with Cyrillic indicates one of the more than sixty villages in the zone. Unbelievable in this area once 180,000 people lived and worked. Finally, we take one by one place on the hand-foot-clothes monitor. With nobody contaminated we leave the zone and return to Kiev. Dutch-and and Belgium Young Generation

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Most people know that in April 1986, the world’s nuclear industry was shattered with the accident of the Chernobyl Nuclear Power Plant (ChNNP) reactor 4 in Ukraine. Consequently, every nuclear debate, every interview, every lecture in schools or universities bring up the Chernobyl topic. It was therefore obvious to the Spanish Young Generation Network (Jóvenes Nucleares, JJNN), a group of young nuclear professionals with a scientific background, that there was a need to expand our awareness, to be able to speak with a solid foundation and full knowledge of the facts about the accident and its consequences.

Hence, on November 20th 2009, 24 JJNN members attended a technical visit to Chernobyl Nuclear Power Plant.

Picture 1: Spanish delegation close to Chernobyl 5th & 6th. Chernobyl 3 & 4 behind. Having entered the 30 km exclusion zone, the Spanish Young Generation members were first brought to the "Agency of Information, International Cooperation and Development" (the Chernobyl Interinform) located in the village of Chernobyl, around 15 kilometers away from the plant. The agency belongs to the Ministry of Emergencies and Affairs of Population Protection from the Consequences of the Chernobyl Catastrophe of Ukraine. In the building, the guide provided the delegation with basic information about the accident and the areas which were affected by it.

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International Youth Nuclear Congress Youth Future Nuclear Back in the bus which would bring the participants to the nuclear power plant, it was possible to see, from one side of the road, the two unfinished cooling towers of Chernobyl Groups 5 and 6, which were under construction when the accident took place. On the other side, could be observed the building devoted to the management of radioactive waste from decommissioning activities as well as the storage of 25.000 fuel elements.

When the delegation arrived to the plant, and after having gone through the required security controls, they were welcomed by the Technical Director for Safety Alexander Y. Novikov, and by the Technical Director for Operation, Sergey A. Kondratenko, in the Mock-up room. The Mock-up room contained three scale models: one of the entire nuclear power plant as it should have been (with six operating units) if the accident hadn‘t taken place, another one of a turbine building, and the third one of a reactor cooling pump. Mr. Novikov, who was working there at the time of the accident, related the event. In front of the scale model of the turbine building, Mr. Kondratenko explained that reactor 2 was definitively shut down in 1991 due to a fire that was declared during an outage of the unit.

After this first general introduction to the functioning of the plant, the Technical Director brought the representatives of the Spanish Young Generation to the control room of reactor 1. In the control room the participants could observe the two instrumentation systems of the reactor core. The first one provided information about more than 1600 high-pressure valves. A specific color code represented the different control rods. The second system enabled analyzing the position of the different control rods through analogical indicators. Mr. Kondratenko explained that the plant worked on the basis of 12 hours shifts (8 to 8) with 4 operators and a head of section in each shift.

The second stop during the visit was the turbine hall. This building was different from the rest of turbine buildings that can be seen in other nuclear power plants around the world. Indeed, while in other plants each reactor may have its own turbine building or, at the most, two reactors sharing the same one, in Chernobyl, the turbine hall (a building of more than 500 meters long) contains the turbines of the four reactors.

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International Youth Nuclear Congress Youth Future Nuclear Before going to the sarcophagus, the delegation paid a visit to Prypiat, the city which was built in 1970 to host the workers of the plant and their families. Between 45.000 and 50.000 people lived there. The city was evacuated more than 24 hours after the accident. The soviet authorities told the inhabitants that they had to take the necessary items for only one week, as they were supposed to come back to their homes. They never did. Since 1986, the city has continuously witnessed looting acts. Back to the plant again, the visitors arrived at the sarcophagus observation point where reactor building 4 can be seen. In this point, there is also the monument which was built in memory of Picture 2 : Prypiat wheel the people who helped building up the sarcophagus. The visit ended in the offices of the observation point where a guide explained the actual state of unit 4. After the accident, a precarious and temporary structure, the so-called sarcophagus, was built in a hurry, without time to develop a proper design. This structure is just a kind of containment building to isolate the damaged reactor. The delegation was informed about the SIP (Shelter Implementation Plan), which has an estimated budget of around 1300 million US dollars, aiming at building a new structure covering and isolating the existing one. The project, once implemented, should enable the manipulation and further extraction of the radioactive materials still on site for further treatment and storage. The SIP, divided in 5 different objectives, foresees the development of 22 different tasks which include, among others, mitigation of the risk of collapse and structural stabilization, dust and water management, fuel containing materials characterization, etc.

During the plant visit, the walks around the surroundings of the plant and inside Prypiat, the effective dose equivalent was measured using a hand-dosimeter for estimating external exposures. The maximum

IYNC Network: Chernobyl 25th Aniversary

International Youth Nuclear Congress Youth Future Nuclear readings were found in exposure situations where radionuclides were accumulated in the wild weeds (e.g. moss). However, in comparison with dose rate levels found in the city of Prypiat, it was observed that close to the moss levels were 10 times higher, and 100 times higher than those ones measured inside ChNNP.

Picture 3: hand-dosimeter at the sarcophagus observation point.

Today there are still around 3,000 people working in the Chernobyl area -plus the security forces surrounding the radiating 30 kilometers off-limits zone.

IYNC Network: Chernobyl 25th Aniversary

International Youth Nuclear Congress Youth Future Nuclear For the long-term, Chernobyl will remain a painful reminder of how important is to maintain higher safety standards and the responsibility that entails this technology. For all the nuclear power professionals, who must always be committed to their best in order to prevent any unexpected situations and also be ready and prepared to act accordingly in the event of unforeseen circumstances: “good enough is not good enough�. Jovenes Nucleares Spanish Young Generation Network

IYNC Network: Chernobyl 25th Aniversary

International Youth Nuclear Congress Youth Future Nuclear

IYNC Bulletin 10

Section 7: Technical Papers