Cernavoda NPP Unit 1 –20 years of living history and counting

At the end of August 2016, according to the most recent international statistics, Unit 1 of Cernavoda NPP registered a  capacity factor of 89.77% since commissioning, occupying the 9th position globally from a total number of 398 nuclear units. With a capacity factor of 91.6% since in service, Romania with two operating nuclear units is on the 1st place in the world.

The nuclear program in Romania was an ambitious vision, an effort of around 240 Romanian companies and thousands of specialists over the years, an ongoing process with a clear perspective for future new build and the means to achieve them.

This is the story of the first nuclear Unit  in Romania and of the specialists who made the vision possible.

In 1968, the first national nuclear program was approved, with the purpose of industrializing nuclear energy in Romania by building nuclear units to ensure the internal consumption and Romania’s energy  independence.

The development of the nuclear program was accompanied by the development of the related horizontal industry and the basic research. In the early years of research in the Romanian nuclear field, significant progress was achieved, comparable with the results obtained by the researchers from Western Europe. The Pitesti Institute  laid the foundation for the manufacturing technology of nuclear fuel and Ramnicu Valcea Research Institute performed ground braking research in the filed of heavy water manufacturing technology. These technologies were subsequently used at Pitesti Nuclear Fuel Plant and at ROMAG heavy water production plant from Drobeta Turnu Severin. The Romanian nuclear program also meant an unprecedented horizontal development, a series of production capacities of different components for nuclear plants being developed in the country, the dream of Ceausescu’s regime being to reflect and even exceed the nuclear industry from other countries.

At the beginning of 1970, we find Romania engaged in a negotiation process with the former Soviet Union in order to implement a VVER 440 MW nuclear reactor technology, a light pressurized reactor with enriched uranium fuel. At that time, this type of reactor was built in the nearby countries: Bulgaria, Czechoslovakia, Germany and Hungary in collaboration with the former Soviet Union. The group of specialists working with the Energetic Design and Studies Institute (ISPE), subordinated to the Ministry of Energy commissioned the sitting studies for the first nuclear plant in Romania. But the plan for implementing the soviet technology is abandoned due mainly to technical aspects, among which the absence of the containment of the VVER 440 nuclear reactors.

On the American continent, the United States and Canada managed to develop their own nuclear technologies. The first commercial CANDU reactor (Canadian Deuterium Uranium) of 100 MWe was commissioned at Douglas Point Nuclear Power Plant, Canada. Subsequently, the project was improved and exported to other countries as CANDU – 6 technology, being implemented in Argentina, South Korea, Romania and China. In 1974, Romania’s Government gives the green light for the manufacturing of nuclear fuel elements with natural uranium and heavy water for the purpose of preparing the construction of the first nuclear plant with Canadian technology.

During the period 1974-1976 Canadian AECL company  (Atomic Energy of Canada Limited), which holds the license for the CANDU 6 reactors and the Romanian Government cooperate to prepare the preliminary studies and in May 1976 the license contracts were signed between the parties.

Romania’s decision to implement the CANDU technology was determined by the very good nuclear safety characteristics, the high operating availability but also by the energy independence policy of the country, supported by the possibilities of the Romanian industry to manufacture equipment, nuclear fuel and heavy water.


The sitting studies for the first Romanian nuclear power plant


At the end of 1978, the contracts with AECL are concluded for the CANDU technology, engineering and technical assistance services as well as for services of equipment procurement and import materials, for the nuclear part of the plant.

During the 1970s, 12 possible locations were under analysis for the first nuclear plant, among which the first 2 were the most accurate from the technical-economical point of view: Cernavoda and Harsova, County of Constanta, both having the Danube as a cooling source. Cernavoda location was chosen due to the structure of the land, reduced seismicity, access possibilities, better impact conditions on the environment.

On January 10th, 1979, the State Committee approved the construction of Cernavoda NPP with 4 units of 660 MWE each on the Cernavoda site.  3 years later, based on the “Study regarding the implications of the construction of Unit 5 at Cernavoda NPP”, drafted by IRNE (the Institute for Nuclear Energy Reactors), the Government decided that the first Romanian nuclear power plant will have 5 units of 706.5 MWe each with a total installed output of 3532.5 MWe.

The designer of the nuclear part of the plant is AECL Canada and the designer of the classical part for the first Unit is ANSALDO-Italy. However, the construction of Cernavoda NPP Unit 1 is ensured by Romanian specialists and with the significant contribution of the Romanian companies at that time.

The CNE Industrial Constructions Consortium also has an important part in providing equipment for the classical part. Starting with Unit 2, the general designer of the plant and the designer of the nuclear part is IRNE. The special designer for the classic part of the plant is ISPE. The plant’s builder is Grupul de santiere Centrale Nuclearoelectrice Cernavoda. The assembly works for the mechanical part are performed by Grupul de Santiere Nuclear Montaj.

The first preparation works on the site of the first nuclear power plant plant begin on April 14th, 1979.

In September 1980, the first concrete is poured at the foundation of reactor 1 building. The foundation represents a concrete plate with a width of approximately 3.3 m, on which the unit’s containment is built. Therefore, the first concrete.

The leadership of the site works is covered by the Romanian party, with reduced technical assistance from Canada and Italy, while the quality insurance requirements and nuclear safety supervision falls under the State Inspectorate for the Control of Nuclear Activities within CSEN.

The construction period was a challenge. A series of delays in complying with the annual investment plans, partly due to the delays in contracting different pieces of equipment, difficulties in selecting the building personnel and its training, fund discontinuity, lead to delays in performing the project, the commissioning term being advanced repeatedly.

The beginning of 1983 marks the completion of an important work and namely the assembly of the containment of Unit 1, a concrete cylinder with an interior diameter of approx. 41 m, a height of approx. 42 m and a wall width of approx. 1 m.

In December of 1985, the reactor vessel (Calandria) of Unit 1 arrives on site from Canada and is installed.

During the period 1985-1987, every year, Cernavoda NPP received the state visit of the Romanian President, Mr. Nicolae Ceausescu, urging the completion of works.

In December 1989, just before the Romanian revolution, the degree of completion of works at Unit 1 is 45%. The building and assembly works at Unit 1 and service buildings continue: the spent fuel pool, the equipment airlock.

In February 1990, the post-revolution Romanian Government approved the continuation of works at Unit 1 of Cernavoda NPP with 5 units of 700 Mw each and the cooperation with the companies AECL, General Electric and Ansaldo, the new term for the commissioning of nuclear units being between 1993-1999.

In July 1990, at the invitation of the Romanian Government, the first PRE-OSART mission of the International Atomic Energy Agency-AIEA from Vienna takes place at Cernavoda NPP. The AIEA mission asses the works and makes recommendations, among which the entrusting of the project leadership by RENEL to a company with experience in the nuclear new build.

Based on the AIEA recommendation, RENEL initiated negotiations with the consortium established by AECL and Ansaldo for the completion of the project. The contract is concluded in August 1991 for the completion, commissioning and initial operation of Unit 1 of Cernavoda NPP. The AECL-Ansaldo consortium developed a strong work force on site to lead the works (Project Management Team – PMT) and collaborated very well with the beneficiary and the Romanian teams. The consortium accepted that the heavy water delivery should be performed by ROMAG instead of being imported from Canada, acknowledging the quality of the Romanian heavy water and the compliance with the reactor’s technical requirements. Another important contract negotiated was the one with Zircatec Canada for supplying the first load of nuclear fuel for Unit 1. In the same time, a contract was negotiated with FCN Pitesti for the supply of 2,300 nuclear fuel bundles out of which 66 were introduced in the first load of the reactor.

On April 6th all systems of Unit 1 are tested and CNCAN issues the authorization for the first criticality on April 10th, 1996.

On a beautiful day in the middle of April of 1996, the nuclear reactor of the  first nuclear power plant in Romania, becomes critical, at 17:32. The Head of Shift, R. Yule mentioned in the shift log: Cernavoda NPP reactor 1 was declared critical for the first time by Gilbert Parent and Nicolae Baraitaru at 17:32.

During the period that followed, the power of the reactors was increased gradually, so that on July 11th, 1996, at 18:22 Unit 1 was connected to the national power grid at 35 MW.

On December 2nd, 1996, Cernavoda NPP entered commercial operation, the power being increased gradually, so that during the night of December 2nd – 3rd 1996, the reactor reached the power of 690 MWe (95% of the nominal power).

According to the contract concluded between RENEL and AECL-Ansaldo consortium, the initial operating period was insured by the latter until June 30th, 1997. Until this date, warranty tests, technical-economical performance indicators analysis and radioprotection assessments were performed and compared with the averages in the nuclear industry, at an international level. Warranty tests and measurements demonstrated that the performance indicators of Unit 1 reached better values than the ones promised by AECL and General Electric by project.

The transfer of the full operating responsibility of Unit 1 from the AECL-Ansaldo consortium, to the Romanian specialists  was prepared daily during the initial operating period and on June 30th, 1997, in the control room of Unit 1, at 17:00, the transfer was concluded.

“Cernavoda NPP Unit 1 has become the symbol of the accomplishment of the Romanian specialists, a best practice of international cooperation, a pinnacle of research design, engineering, a landmark that put Romania on the map of nuclear power plant operators. Today’s results of Units 1 and 2 of Cernavoda NPP encourage us to support the future development of nuclear power in Romania, as this energy source has proven its benefits to ensuring the energy supply and achieving the environmental goals adopted by Romania as a member state of the European Union. 20 years of commercial operation is a celebration and also a time to reflect about the future, as SNN is committed to extend the life of Unit 1. Technical analysis on refurbishment efforts and requirements is under way and expected to be completed by 2017”, said Daniela Lulache, CEO of Nuclearelectrica.


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