# Temelín Nuclear Power Station

Temelín Nuclear Power Station (Czech: Jaderná elektrárna Temelín, abbreviation ETE) is a nuclear power plant in Temelín, Czech Republic. It is owned by ČEZ Group, which employs 1,000 workers at the site. The adjacent castle Vysoký Hrádek serves as an information centre.
In 2003, the Temelín Nuclear Power Plant, with its 2,180 MW of installed capacity, became the largest power resource in the Czech Republic and the largest source of zero-emission electricity generation by far.

## History

Planning for the Temelín Nuclear Power Station began in the late 1970s, and the final project was submitted in 1985. Construction of four operating units began in 1987. The project was expected to be completed in 1991, with estimated building costs of 35 billion CSK. Six villages were demolished by the then-Communist government to make way for the power station.
After the Velvet Revolution in 1990, the Czechoslovak government decided to cease construction of the third and fourth reactors; work continued on the first two reactors, however. In the 1990s, alterations to the original design were made by Westinghouse, in conjunction with SUJB and the IAEA, to bring reliability and safety levels into conformance with Western European standards. The standards audit was carried out by Halliburton NUS. As part of the alterations, information and control systems were added, electrical modifications carried out, and cabling, reactor core, and fuel elements were replaced. In 1993, the Czech government decided to complete the plant in the face of delays and cost overruns, with expected completion at the time estimated for 1997. In 1994, an opinion poll reported that 68% of Czech citizens were in favour of nuclear power development.
By 1998, construction was still not completed, and costs reached 71 billion CZK. The Czech government again reconsidered completion of the plant. In 1999, the decision was made to continue, projecting completion to 2000, with a maximum cost of 98.6 CZK billion. The project was controversial; national and international (mainly Austrian) opposition was stronger than in the early 1990s, and public opinion on the project fluctuated. In a 1999 opinion poll, 47% of Czech citizens were in favour and 53% against nuclear power development, a fall from 1994. In subsequent years, the same poll showed 63% in favour and 37% against in 2000 and 58% in favour and 42% against in 2001.
In September and October 2000, Austrian anti-nuclear protesters demonstrated against the Temelín Nuclear Power Plant and at one stage temporarily blocked all 26 border crossings between Austria and the Czech Republic.
As a result of cost overruns, political changes, and design changes to the plant, reactor 1 began commercial operations in June 2002, and reactor 2 on 18 April 2003. As of 2023, the two reactors had produced 272 TWh, or 272.000.000.000 kWh of electricity, with no CO2 emissions. Assuming a price level of CZK 2 per kWh, this amounted to 544 billion CZK. As the initial investment was CZK 100 billion, the plant had turned a profit. In 2022 alone, the operators of the plant earned CZK 80 billion, as a result of the Russian invasion of Ukraine and the resulting energy crisis.

### Melk Protocol

The Melk Protocol, signed on 12 December 2000 in Melk, Austria, is the result of negotiations between the Czech and Austrian governments, led by Czech prime minister Miloš Zeman and Austrian chancellor Wolfgang Schüssel, with the participation of European Commissioner Günter Verheugen. The aim of the protocol was to resolve disputes over the Temelín plant, with Austria raising several concerns about its safety and procedures. The Czech Republic committed itself to some above-standard procedures (e.g., notification of events at Temelín to Austria, and a more stringent environmental impact assessment). Consequently, Austria recognised the importance of EU enlargement and agreed that the free movement of goods and people must be preserved (this clause was a response to the blockade of Czech–Austrian border crossings by Austrian anti-nuclear activists). The protocol is not legally binding.

## Technical data

In 2013, the reactors were uprated from 3,000 MW thermal output to 3,120 MW, bringing the total output to 1,003 MWe net and 1,056 MWe gross. In 2015, turbomachinery was updated, bringing total output to the current 1,026 MWe net and 1,080 MWe gross.
| Station | Reactor type | Net capacity | Gross capacity | Thermal output | Initial criticality | Grid date | Exp. shutdown |
| Temelín 1 | VVER 1000 type V 320 PW | 1,026 MWe | 1,080 MWe | 3,120 MW | Dec 2000 | Jun 2002 | 2062 |
| Temelín 2 | VVER 1000 type V 320 PW | 1,026 MWe | 1,080 MWe | 3,120 MW | Dec 2002 | Apr 2003 | 2063 |

### Reactor vessel (core)

* The reactor contains 163 fuel assemblies and 61 control rod assemblies.
* A single assembly has the shape of ~4.5m long hexagon, and inside are 312 fuel rods.
* The fuel rods contain stacked cylindrical fuel pellets.
* Fuel enrichment: max. 5% (average 3.5%) of $^{235}$U (fissile isotope)
* Fuel load UO$_2$: 92t (the reactor splits about 3 kg of uranium every day).
* Fuel replacement cycle: 4 years (1/4 is changed yearly).
* Vessel height: ~11m; outside diameter: ~4.5m; wall thickness: 193 mm.
* The vessel is designed for up to 17.6MPa at 350 °C.
* The vessel is made of high-quality, low-alloy chrome-nickel-molybdenum-vanadium steel.
* For the reactor to produce 1W of thermal output, 30 billion fissions of uranium-235 must take place every second. For a coal power station to produce the same output, 1,500,000,000 billion carbon atoms must be burned.

### Reactor cooling system

* Number of cooling loops: 4
* Quantity of primary circuit coolant: 337 m$^3$
* Operating pressure: 15.7MPa
* Coolant inlet temperature: approx. 290 °C (554F)
* Coolant outlet temperature: approx. 320 °C (608F)
* Coolant flow through reactor: 23.5 m$^3$/s

### Steam generator

* Number per reactor unit: 4
* Steam delivered per one generator: 1,470 t/hour
* Steam outlet pressure: 6.3MPa
* Steam outlet temperature: 278.5 °C (533.3F)

### Cooling circuit

* The plant has four cooling towers (each unit has two towers).
* Each tower has a height of 150 metres (490 ft), a diameter of 130 metres (430 ft), and an external wall surface area of 44,000 square metres (470,000 sq ft).
* Pure water is evaporated in cooling tower (~0.3m$^3$/s).
** The water needs to be constantly refilled.

### Protective envelope (containment)

* Height of cylindrical section: 38m
* Inside diameter of cylindrical section: 45m
* Wall thickness: 1.2m
* Thickness of steel lining: 8mm

### Turbine generator set

* Number per unit: 1
* Number of steam turbine sections: 1 high-pressure and 3 low-pressure
* Speed: 3,000 rpm
* Voltage on alternator's terminal: 24kV
* Alternator cooling: hydrogen – water

## Reliability

IAEA data show that reactor 1 reaches a cumulative operating factor of about 63%, and reactor 2 of about 76%. The cumulative operating factor figures for Temelín NPP reactors are lower than the figures of similar reactors operated in Russia, where it is around 80–87%.
ČEZ has increased the operating factor as well as production in recent years, and the plant reached 84% in 2012, with a total record production of 15 TWh.

## New reactors

Plans to build all four original reactors were reopened in 2005. However, in 2014, the prospective plans were cancelled.
In 2007, planning was suspended because the incoming government agreed not to promote nuclear energy. However, in July 2008, ČEZ requested the Ministry of the Environment conduct an environmental impact assessment for two additional reactors. In 2009, regional approval was granted for the new build. In August 2009, ČEZ sought bids for two pressurized water reactors. Shortly after the Fukushima nuclear accident, prime minister Petr Nečas announced that the construction of new reactors would continue according to original plans but with the tender selection delayed until 2013.
In July 2012, ČEZ opened public-contract bids for completing the Temelín Nuclear Power Plant in the presence of the bidders—Areva; a consortium of the Westinghouse Electric Company; and a consortium of ŠKODA JS, Atomstroyexport, and Gidropress. In October 2012, Areva's bid was excluded from further evaluation, as they had not met statutory requirements.
In March 2013, a Russian-led consortium, comprising Atomstroyexport, Gidropress, and Škoda, signed contracts with the Czech companies ZAT, Hochtief CZ, and UJV Rez, for the construction of two new nuclear reactor units for Temelín-3 and Temelín-4, both of which being MIR-1200 (Modernised International Reactor). ZAT would supply automated systems for the plant, Hochtief CZ would be responsible for construction of the nuclear island, and UJV Rez would help compile project documentation for the nuclear and turbine islands and also create working documentation for construction of the plant. A statement said the consortium was aiming for a "localisation level" of 75 percent. The other running project for the contract was Westinghouse, with its AP1000 reactor. The winner of the contract was scheduled to be announced at the end of 2013.
In April 2014, ČEZ cancelled the project after the Czech government stated it did not plan to provide guarantees or other mechanisms to support the construction of low-emission power plants following discussions in the EU. The ČEZ CEO stated:
   While originally the project was fully economically feasible given the market price of electricity and other factors, today all investments into power plants, whose revenues depend on sales of electricity in the free market, are threatened.
In 2021, Westinghouse was contracted to upgrade the instrumentation and control systems of the power plant in a nine-year project.