Referential technologies

In terms of the technical solution, only sources with pressurized water reactors (PWR) are considered, which represent the currently best available technology from the standpoint of environmental impact with a range of safety benefits. Other reasons for choosing these reactors are mainly:

  • world-wide prevalence of pressurized water reactors - account for almost 60% of the operated nuclear power plants in the world,
  • designs tested by 50 years of operation and refined following the current security standards,
  • the ongoing construction of these designs in Europe and elsewhere in the world,
  • ČEZ’s operational experience with this type of power plant - Dukovany and Temelín Nuclear Power Plants are Generation II PWR,
  • capacity corresponding to optimal utilization of current locations and needs of the Czech Republic in future years including extended possibilities of power control.

The selection of supplier will be based on a combination of a large number of factors - legislative, environmental, safety, technical, economic and financial. However, all suppliers will have to prove, together with the legal requirements, the fulfilment of the so-called envelope parameters of the environmental impact, which are assessed in the EIA process.

The Generation III+ PWR-unit power plant can be supplied by a number of world-renowned manufacturers. The following designs are considered to be reference designs:

  • AP1000 design           Westinghouse Electric Company LLC (USA),
  • APR1000 design         Korea Hydro&Nuclear Power (South Korea),
  • ATMEA1 design        AREVA NP/Mitsubishi Heavy Industries (France/Japan),
  • EPR design                 AREVA NP (France),
  • EU-APR design           Korea Hydro&Nuclear Power (South Korea),
  • HPR1000 design         China General Nuclear Power Corporation (China),
  • VVER-1200E design  Rosatom (Russia).

The power plant supplier will be selected in the next stages of design preparation. In the course of the EIA processes, the environmental impacts were assessed for the upcoming new nuclear sources at the Dukovany site and at the Temelín site. Within the framework of these assessments, environmental as well as safety requirements for all the reactor types are the same and their impacts are considered in their potential maximum (it means that parameters used for impact assessment conservatively cover the parameters of the facility of all the prospective suppliers). The supplier of the NNS therefore may be another manufacturer, whose design will observe the envelope parameters, used for the environmental impact assessment.

Reference design: AP1000

It is the design of Westinghouse Electric Company LLC, USA. Thermal power of one unit is approx. 3,415 MWt, electric power is approx. 1,200 MWe. First four units of the Sanmen and Haiyang power plants (both in China) are already in operation. The Vogtle project (USA) is currently under construction. All these units have a building permit and are already under construction. The AP1000 design was granted a combined license (design + site) in the USA to enable construction. In 2017, it also went through the GDA process in the UK.

Development of the AP1000 pressurized water reactor technology has been in progress more than 15 years and it is based on knowledge and experience gained through successful 50-year operation of more than 100 commercial power plants of the Westinghouse company. 

The primary circuit of the reactor of the AP1000 design consists of two loops of the main circulation pipeline connected to the reactor. Each loop has a steam generator, two main circulation pumps, one hot leg, and two cold legs for the reactor coolant circulation. The primary circuit also includes a pressurizer.

1

Fuel handling building

7

Reactor

2

Containment building

8

Integrated upper block of reactor

3

Containment

9

Pressurizer

4

Coolant storage tank for passive containment cooling system

10

Main control room

5

Steam generators

11

Feed water pumps

6

Main circulation pumps

12

Turbogenerator (turbine and generator)

The main safety systems of the AP1000 include:

  • passive emergency core cooling system,
  • passive residual heat removal system,
  • passive system of pressure relief and heat removal from the containment,
  • hydrogen burning system in the containment,
  • passive fuel melt localization and stabilization system.

In case of no-loss-of-coolant accidents from the primary circuit, heat is removed from the core through the residual heat removal system. The reactor coolant is circulated through a heat exchanger placed in a large-capacity tank inside the containment.

In case of loss-of-coolant accidents from the primary circuit, heat is removed through the emergency core cooling system and from it to the large-capacity tank inside the containment. The passive emergency core cooling system consists of two pressure replenishment reservoirs filled with reactor coolant with the working pressure of the primary circuit, two hydro-accumulators, a large-capacity tank inside the containment, and a safety depressurization system (depressurization valves). The system is also designed to perform the function of high pressure injection of boric acid solution. After heating the water in the large-capacity tank, it evaporates into the space of the containment. The atmosphere of the containment is cooled through the steel walls of the containment by air circulation in combination with spraying of the outer walls of the containment. The integrity of the containment is ensured, in addition to the system of pressure relief and heat removal from the containment, also by the hydrogen burning system in the containment (passive hydrogen recombiners).

In the event of a severe accident, heat removal is ensured by flooding the reactor shaft with water from the large-capacity tank located in the containment and cooling the reactor pressure vessel from the outside. After heating the water in the large-capacity tank, it evaporates into the space of the containment. The atmosphere of the containment is cooled through the steel walls of the containment by air circulation in combination with spraying of the outer walls of the containment. The design is equipped with hydrogen burners to ensure the integrity of the containment even with increased hydrogen production during a severe accident.

 Reference design: APR1000

It is the design of Korea Hydro&Nuclear Power (KHNP), South Korea. The development of the APR1000 design commenced in 2014 and was based on the APR+ and APR1400 designs in order to develop a medium-sized reactor with the electrical power of approximately 1000 MWe. The APR1000 design ideologically builds on the previous OPR1000 designs licensed and operated in South Korea. The thermal power of one APR1000 unit is approximately 2,825 MWt. The APR1000 design is currently under development. The APR+ design on which the APR1000 design is based was licensed in South Korea in 2014. The APR1400 project is licensed in South Korea and the United Arab Emirates.

The primary circuit of the reactor of the APR1000 design consists of two loops of the main circulation pipeline. Each loop has a steam generator, two main circulation pumps, one hot leg, and two cold legs for the reactor coolant circulation. The primary circuit also includes a pressurizer.

1

Containment building

10

Diesel generators

2

Turbine hall

11

Main control room

3

Auxiliary building

12

Moisture separator and reheater

4

Spent nuclear fuel storage pool

13

Deaerator

5

Pressurizer

14

Turbine

6

Steam Generator

15

Low-pressure heaters

7

Safety injection tank

16

High-pressure heaters

8

Main circulation pump

17

Turbine feedwater pumps

9

Reactor vessel

 

 

The main safety systems of the APR1000 include:

  • active emergency core cooling system,
  • active residual heat removal system,
  • passive residual heat removal system,
  • active system of high-pressure injection of boric acid solution,
  • active system of pressure relief and heat removal from the containment,
  • hydrogen burning system in the containment,
  • fuel melt localization and stabilization system,
  • intermediate cooling circuit and essential service water system,
  • special intermediate cooling circuit and essential service water system.

In case of no-loss-of-coolant accidents from the primary circuit, heat is removed from the core first through the secondary circuit using the passive residual heat removal system and then through the active residual heat removal system. In the first phase, the reactor coolant is circulated through the steam generators, and there heat is transferred through the steam generator tubes to heat exchangers placed in the vicinity of the containment. Subsequently, the heat is removed by circulation through the heat exchanger of the residual heat removal system and transferred to the intermediate cooling circuit. Both the passive residual heat removal system and the active residual heat removal system are designed in four divisions.

In case of loss-of-coolant accidents from the primary circuit, heat is removed in the first phase through the emergency core cooling system and then by means of the residual heat removal system. The active emergency core cooling system consists of four hydro accumulators and four active make-up divisions. Heat is removed from the containment through the active system of pressure relief and heat removal from the containment, allowing the interior of the containment to be sprayed. Heat is removed into the intermediate cooling circuit. The heat from the intermediate cooling circuit is transferred to the essential service water system and from it to the atmosphere. The systems are implemented in four divisions. The integrity of the containment is ensured, in addition to the system of pressure relief and heat removal from the containment, also by the hydrogen burning system in the containment (passive hydrogen recombiners). The high-pressure boric acid solution injection system provides an alternative way of ensuring the reactor subcriticality.

In case of a severe accident, the design is equipped with a fuel melt localization and stabilization system. The melt is trapped in a special device and then flooded from the large-capacity tank placed in the containment. The heat from the melt and the containment is transferred to the special intermediate cooling circuit. The heat from the special intermediate cooling circuit is transferred to the special essential service water system and from it to the atmosphere. The design is equipped with other passive hydrogen recombiners to ensure the integrity of the containment even with increased hydrogen production during a severe accident.

Reference design:  ATMEA1

It is the design of the joint venture of AREVA NP/Mitsubishi Heavy Industries, France/Japan. Thermal power of one unit is approx. 3300 MWt, electric power is approx. 1,200 MWe. The design is not yet under construction but has undergone a positive safety assessment by the IAEA, French and Canadian nuclear regulatory body. The design is being considered for the Sinop site, Turkey.

The primary circuit of the reactor of the ATMEA1 design consists of three loops of the main circulation pipeline. Each loop has a steam generator, main circulation pump, one hot, and one cold leg for the reactor coolant circulation. The primary circuit also includes a pressurizer.

1

Reactor

7

Active auxiliary service building

2

Steam generators

8

Radioactive fuel handling building

3

Hydro accumulator

9

Auxiliary service building

4

Pressurizer

10

Dieselgenerator station building

5

Reactor building

11

Turbine hall

6

Fuel building

12

Safety system building

The main safety systems of the ATMEA1 include:

  • active emergency core cooling system,
  • active residual heat removal system,
  • active system of high-pressure injection of boric acid solution,
  • emergency steam generator feed water system,
  • active system of pressure relief and heat removal from the containment,
  • hydrogen burning system in the containment,
  • fuel melt localization and stabilization system,
  • intermediate cooling circuit and essential service water system,
  • special intermediate cooling circuit and essential service water system.

In case of no-loss-of-coolant accidents from the primary circuit, heat is removed from the core first through the secondary circuit by means of the emergency steam generator feed water system and then through the residual heat removal system. In the first phase, the reactor coolant is circulated through the steam generators, and there heat is transferred through the steam generator tubes to the secondary circuit and the steam generated is removed to the atmosphere. Subsequently, the heat is removed by circulation through the heat exchanger of the residual heat removal system and transferred to the intermediate cooling circuit. Both the emergency steam generator feed water system and the residual heat removal system are designed in three divisions.

In case of loss-of-coolant accidents from the primary circuit, heat is removed in the first phase through the emergency core cooling system and then by means of the residual heat removal system. The active emergency core cooling system consists of three hydro accumulators and three active make-up divisions. Heat is removed from the containment through the active system of pressure relief and heat removal from the containment, allowing the interior of the containment to be sprayed. The system is implemented in three divisions. Heat is removed into the intermediate cooling circuit. The heat from the intermediate cooling circuit is transferred to the essential service water system and from it to the atmosphere. The systems are implemented in three divisions. The integrity of the containment is ensured, in addition to the system of pressure relief and heat removal from the containment, also by the hydrogen burning system in the containment (passive hydrogen recombiners). The high-pressure boric acid solution injection system provides an alternative way of ensuring the reactor subcriticality.

In case of a severe accident, the design is equipped with a fuel melt localization and stabilization system. The melt is trapped in a special device and then flooded from the large-capacity tank placed in the containment. The heat from the melt and the containment is transferred to the special intermediate cooling circuit. The heat from the special intermediate cooling circuit is transferred to the special essential service water system and from it to the atmosphere. The design is equipped with other passive hydrogen recombiners to ensure the integrity of the containment even with increased hydrogen production during a severe accident.

Reference design: EPR

It is the design of AREVA NP, France. Thermal power of one unit is approx. 4616 MWt, electric power is approx. 1750 MWe. The Olkiluoto 3 (Finland) and Flamanville (France) projects are in the phase of construction, it is completed in the Taishan site (China). The design is also implemented in the UK (Hinkley Point C).

The primary circuit of the EPR reactor consists of four loops of the main circulation pipeline. Each loop includes a steam generator, main circulation pump, one hot, and one cold leg for the reactor coolant circulation. The primary circuit also includes a pressurizer.

1

Containment building

6

Spent nuclear fuel storage pool

2

Reactor

7

Turbine hall

3

Steam generators

8

Safety system building

4

Pressurizer

9

Auxiliary service building

5

Main circulation pump

10

Diesel generators

The main safety systems of the EPR include:

  • active emergency core cooling system,
  • active residual heat removal system,
  • active system of high-pressure injection of boric acid solution,
  • emergency steam generator feed water system,
  • hydrogen burning system in the containment,
  • fuel melt localization and stabilization system,
  • intermediate cooling circuit and essential service water system,
  • special intermediate cooling circuit and essential service water system.

In case of no-loss-of-coolant accidents from the primary circuit, heat is removed from the core first through the secondary circuit by means of the emergency steam generator feed water system and then through the residual heat removal system. In the first phase, the reactor coolant is circulated through the steam generators, and there heat is transferred through the steam generator tubes to the secondary circuit and the steam generated is removed to the atmosphere. Subsequently, the heat is removed by circulation through the heat exchanger of the residual heat removal system and transferred to the intermediate cooling circuit. Both the emergency steam generator feed water system and the residual heat removal system are designed in four divisions.

In case of loss-of-coolant accidents from the primary circuit, heat is removed in the first phase through the emergency core cooling system and then by means of the residual heat removal system. The active emergency core cooling system consists of four hydro accumulators and four active make-up divisions. Heat is removed from the containment by means of the residual heat removal system from which the heat is transferred to the intermediate cooling circuit. The heat from the intermediate cooling circuit is transferred to the essential service water system and from it to the atmosphere. The systems are implemented in four divisions. The integrity of the containment is ensured, in addition to the residual heat removal system, also by the hydrogen burning system in the containment (passive hydrogen recombiners). The high-pressure boric acid solution injection system provides an alternative way of ensuring the reactor subcriticality.

In case of a severe accident, the design is equipped with a fuel melt localization and stabilization system. The melt is trapped in a special device and then flooded from the large-capacity tank placed in the containment. The heat from the melt and the containment is transferred to the special intermediate cooling circuit. The heat from the special intermediate cooling circuit is transferred to the special essential service water system and from it to the atmosphere. The design is equipped with other passive hydrogen recombiners to ensure the integrity of the containment even with increased hydrogen production during a severe accident.

Reference design: EU-APR

It is the design of Korea Hydro&Nuclear Power (KHNP), South Korea. Thermal power of one unit is approx. 4000 MWt, electric power is approx. 1455 MWe. This is the European version of the APR1400 design. The APR1400 Shin Kori 3 unit (South Korea) is in operation, another Shin Kori 4 unit will be started up. The Shin Kori 5-6 (South Korea) and Shin Hanul 1-2 (South Korea) designs are under construction, with four units being completed in Barakah (United Arab Emirates). In these countries, the APR1400 design has received a construction permit.

The primary circuit of the reactor of the EU-APR design consists of two loops of the main circulation pipeline. Each loop has a steam generator, two main circulation pumps, one hot leg, and two cold legs for the reactor coolant circulation. The primary circuit also includes a pressurizer.

1

Reactor

6

Turbine hall

2

Steam generator

7

Active auxiliary service building

3

Turbogenerator

8

Auxiliary service and safety system building

4

Reactor building

9

Ventilation stack

5

Auxiliary service building

 

 

The main safety systems of the EU-APR include:

  • active emergency core cooling system,
  • active residual heat removal system,
  • active system of high-pressure injection of boric acid solution,
  • emergency steam generator feed water system,
  • active system of pressure relief and heat removal from the containment,
  • hydrogen burning system in the containment,
  • fuel melt localization and stabilization system,
  • intermediate cooling circuit and essential service water system,
  • special intermediate cooling circuit and essential service water system.

In case of no-loss-of-coolant accidents from the primary circuit, heat is removed from the core first through the secondary circuit by means of the emergency steam generator feed water system and then through the residual heat removal system. In the first phase, the reactor coolant is circulated through the steam generators, and there heat is transferred through the steam generator tubes to the secondary circuit and the steam generated is removed to the atmosphere. Subsequently, the heat is removed by circulation through the heat exchanger of the residual heat removal system and transferred to the intermediate cooling circuit.

In case of loss-of-coolant accidents from the primary circuit, heat is removed in the first phase through the emergency core cooling system and then by means of the residual heat removal system. The active emergency core cooling system consists of four hydro accumulators and four active make-up divisions. Heat is removed from the containment through the active system of pressure relief and heat removal from the containment, allowing the interior of the containment to be sprayed. The system is implemented in four divisions. Heat is removed into the intermediate cooling circuit. The heat from the intermediate cooling circuit is transferred to the essential service water system and from it to the atmosphere. The systems are implemented in four divisions. The integrity of the containment is ensured, in addition to the system of pressure relief and heat removal from the containment, also by the hydrogen burning system in the containment (passive hydrogen recombiners). The high-pressure boric acid solution injection system provides an alternative way of ensuring the reactor subcriticality.

In case of a severe accident, the design is equipped with a fuel melt localization and stabilization system. The melt is trapped in a special device and then flooded from the large-capacity tank placed in the containment. The heat from the melt and the containment is transferred to the special intermediate cooling circuit. The heat from the special intermediate cooling circuit is transferred to the special essential service water system and from it to the atmosphere. The design is equipped with other passive hydrogen recombiners to ensure the integrity of the containment even with increased hydrogen production during a severe accident.

Reference design: HPR1000

The HPR1000 reactor is a design of China General Nuclear Power Corporation (CGN), China. Thermal power of one unit is approx. 3190 MWt, electric power is approx. 1160 MWe. There are two units under construction at Fuqing (China), where the design has received a construction permit.

The primary circuit of the reactor of the HPR1000 design consists of three loops of the main circulation pipeline. Each loop has a steam generator, main circulation pump, one hot, and one cold leg for the reactor coolant circulation. The primary circuit also includes a pressurizer.

1

Reactor building

13

RAW processing building

2

Fuel building

14

Backup cooling system

3

Auxiliary service building

15

Turbine hall

4

Safety system building A

16

Electrical system building of turbine island

5

Safety system building B

17

Main transformer

6

Safety system building C

18

Auxiliary transformer

7

Inlet building

19

ESW pumping station A

8-10

Emergency diesel generator building A/B/C

20

ESW pumping station B

11-12

SBO diesel generator building

21

Cooling water pumping station

The main safety systems of the HPR1000 include:

  • active emergency core cooling system,
  • active residual heat removal system,
  • passive residual heat removal system,
  • active system of high-pressure injection of boric acid solution,
  • emergency steam generator feed water system,
  • active system of pressure relief and heat removal from the containment,
  • hydrogen burning system in the containment,
  • fuel melt localization and stabilization system,
  • intermediate cooling circuit and essential service water system,
  • special intermediate cooling circuit and essential service water system.

In case of no-loss-of-coolant accidents from the primary circuit, heat is removed from the core first through the secondary circuit by means of the emergency steam generator feed water system and then through the residual heat removal system. In the first phase, the reactor coolant is circulated through the steam generators, and there heat is transferred through the steam generator tubes to the secondary circuit and the steam generated is removed to the atmosphere. Subsequently, the heat is removed by circulation through the heat exchanger of the residual heat removal system and transferred to the intermediate cooling circuit. Both the emergency steam generator feed water system and the residual heat removal system are designed in three divisions. In addition, a passive heat removal system can be used as a backup, which can remove heat from the steam generators via an intermediate circuit into tanks located on the outside of the containment. Heat is then transferred to the surroundings by evaporation.

In case of loss-of-coolant accidents from the primary circuit, heat is removed in the first phase through the emergency core cooling system and then by means of the residual heat removal system. The active emergency core cooling system consists of three hydro accumulators and three active make-up divisions. Heat is removed from the containment by means of the residual heat removal system from which the heat is transferred to the intermediate cooling circuit. The heat from the intermediate cooling circuit is transferred to the essential service water system and from it to the atmosphere. The systems are implemented in three divisions. The integrity of the containment is ensured, in addition to the residual heat removal system, also by the hydrogen burning system in the containment (passive hydrogen recombiners). The high-pressure boric acid solution injection system provides an alternative way of ensuring the reactor subcriticality.

In the event of a severe accident, heat removal is ensured by flooding the reactor shaft with water from the tank located in the containment and cooling the reactor pressure vessel from the outside. The heat from the melt and the containment is transferred to the special intermediate cooling circuit. The heat from the special intermediate cooling circuit is transferred to the special essential service water system and from it to the atmosphere. The design is equipped with passive hydrogen recombiners to ensure the integrity of the containment even with increased hydrogen production during a severe accident.

Reference design: VVER-1200E

This is the European version of the VVER-1200 design from Rosatom, Russia. Thermal power of one unit is approx. 3212 MWt, electric power is approx. 1198 MWe. The V-491 designs of Leningrad II NPP in the Russian Federation and Ostrovets in Belarus are under construction. Unit 1 of Leningrad II power plant is already in operation. The design was also selected for construction in Finland (Hanhikivi) and Hungary (Paks II). In Finland and Hungary, the licensing process is under way, and in Russia and Belarus the design has received a construction permit.

The primary circuit of the reactor of the VVER-1200E consists of four loops of the main circulation pipeline. Each loop has a steam generator, main circulation pump, one hot, and one cold leg for the reactor coolant circulation. The primary circuit also includes a pressurizer.

1

Reactor building

9

Reactor

2

Turbine hall

10

Steam generator

3

Control system building

11

Main circulation pump

4

Active auxiliary service building

12

Pressurizer

5

Auxiliary service building

13

Hydroaccumulators

6

Dieselgenerator station building

14

Passive heat removal tanks

7

Auxiliary diesel generator station building

15

Turbogenerator

8

Safety system building

 

 

The main safety systems of the VVER-1200E include:

  • active emergency core cooling system,
  • active residual heat removal system,
  • passive residual heat removal system,
  • active system of high-pressure injection of boric acid solution,
  • emergency steam generator feed water system,
  • active system of pressure relief and heat removal from the containment,
  • passive system of pressure relief and heat removal from the containment,
  • hydrogen burning system in the containment,
  • fuel melt localization and stabilization system,
  • intermediate cooling circuit and essential service water system.

In case of no-loss-of-coolant accidents from the primary circuit, heat is removed from the core first through the secondary circuit by means of the emergency steam generator feed water system and then through the residual heat removal system. In the first phase, the reactor coolant is circulated through the steam generators, and there heat is transferred through the steam generator tubes to the secondary circuit and the steam generated is removed to the atmosphere. Subsequently, the heat is removed by circulation through the heat exchanger of the residual heat removal system and transferred to the intermediate cooling circuit. Both the emergency steam generator feed water system and the residual heat removal system are designed in four divisions. In addition, a passive heat removal system can be used as a backup for accidents with loss of all power supply sources, which can remove heat from the steam generators via an intermediate circuit into tanks located on the outside of the containment. Heat is then transferred to the surroundings by evaporation.

In case of loss-of-coolant accidents from the primary circuit, heat is removed in the first phase through the emergency core cooling system and then by means of the residual heat removal system. The active emergency core cooling system consists of four hydro accumulators and four active make-up divisions. Heat is removed from the containment through the active system of pressure relief and heat removal from the containment, allowing the interior of the containment to be sprayed. The system is implemented in four divisions. Heat is removed into the intermediate cooling circuit. The heat from the intermediate cooling circuit is transferred to the essential service water system and from it to the atmosphere. The systems are implemented in four divisions. The integrity of the containment is ensured, in addition to the system of pressure relief and heat removal from the containment, also by the hydrogen burning system in the containment. The high-pressure boric acid solution injection system provides an alternative way of ensuring the reactor subcriticality.

In case of a severe accident, the design is equipped with a fuel melt localization and stabilization system. The melt is trapped in a special device which is flooded from the large-capacity tank placed in the containment before melt-through of the reactor pressure vessel. The heat from the melt and the containment is removed by means of a passive pressure relief and heat removal from the containment through an intermediate circuit to the tanks located on the outside of the containment. Heat is then transferred to the surroundings by evaporation. The design is equipped with other passive hydrogen recombiners to ensure the integrity of the containment even with increased hydrogen production during a severe accident.