30 September 2023

70+ Years of Nuclear Power

World Nuclear Power Reactors 1951–2023

The WNISR Interactive DataViz

Interactive visualization developed by World Nuclear Industry Status Report (WNISR) and Visionscarto
with support of the current funders of WNISR, and in particular the Heinrich Böll Foundation EU and the Natural Resources Defense Council (NRDC).
This version is based on a first edition hosted by the Bulletin of the Atomic Scientists 2017-2020 with support of the Pulitzer Center on Crisis Reporting.

Frequently Asked Questions (FAQ)


The information in this data visualization is based on the World Nuclear Industry Status Report (WNISR) Database, a Mycle Schneider Consulting Project, globally updated to 1 January 2023. Additional updates will be made continuously as required. The database covers commercial nuclear power reactors for which construction has or had started and does not include “planned” or “projected” power reactors. It also excludes research, heating or military reactors that do or did not generate power.

Sources of Data

The World Nuclear Power Reactor Data Visualization is based on the WNISR Nuclear Reactor Database. Historic data are drawn from the International Atomic Energy Agency's (IAEA) Power Reactor Information System (PRIS), from the World Nuclear Association's (WNA) online database, and from WNISR’s own research. The annual WNISR provides over one thousand bibliographical references, all of which are available on the WNISR website.

Information on reactor characteristics (type, model, capacity, provider, operator) are mainly drawn from IAEA-PRIS. Provider groupings by country or international consortia have been established by WNISR.

The main discrepancies between IAEA- and WNISR-data relating to reactor constructions:

• IAEA data depends on information provided by Member States; WNISR research attempts to establish which construction projects can be considered “active”. If several credible sources—either in the open literature or from the WNISR's international network of contacts—corroborate a given status, a project will be either added to or withdrawn from the IAEA's list of reactors “under construction”.

• The IAEA sometimes creates “new” construction-start dates, when there has been a significant interruption in the building of a nuclear power plant, as well as in other cases usually involving construction starts prior to the 1980s. WNISR tries to document interruptions but does not modify the original construction start date, unless the changes reflect an evolution of the construction start definition itself.

• Construction data in IAEA-PRIS have not only changed over the years for some reactors; some reactors have simply disappeared from the system. Not all of those changes are reflected in the WNISR database.


Construction Start

The construction-start date is considered to be the moment the concrete base slab of the reactor building is being poured. Site preparation and excavation work are not included. For floating reactors (Russia and China), as no concrete is being poured, WNISR uses the “keel laying ceremony” of the barge as the construction-start date.

Construction Suspension or Abandonment

Over the years, in many cases reactor construction has been suspended or abandoned. Suspension and cancellation apply only to “constructions” and not to “projected” or “planned” reactors. Reactors enter the WNISR statistical database only when construction has started according to the above definition.

Temporary Suspension

A reactor construction that was once suspended but has resumed.

Indefinite Suspension

A construction declared “suspended”—by the operator, authorities, regulators, etc., or listed as “suspended” by IAEA-PRIS—that has not resumed as of 1 January 2023, and has no date or real prospect of restart. This includes non-official suspensions, for which WNISR has determined that there is de facto no active construction and no prospect of timely restart.

• Abandoned Construction

A construction declared cancelled, by the operator, authorities, regulators, etc. or through any other official decision, or listed as “cancelled” in IAEA-PRIS. Some cancellations have been listed in the IAEA publication series “Nuclear Power Reactors in the World” (Reference Data Series No 2) that are not yet included in the WNISR database. This includes non-official abandonments, for which WNISR has determined that there is de facto no active construction and no prospect of restart.

Reactor Startup (Grid Connection)

The WNISR definition of reactor startup is its grid connection. In the case of reactor construction, the expected startup date is not always expressed in terms of grid connection, but also as “commissioning”, “completion”, “commercial operation”, or other, similar terminology. Expected startup is not always connected to a precise date; rather, it can be general as in “early 2021” or as in “second semester 2023”. WNISR uses “best estimates”, based on a variety of sources, when providing expected startup dates, as of January 2023, unless otherwise noted.

Construction Time (Duration Since First Construction Start)

The total construction time is the entire length of a reactor's construction period, from construction start until it is (or is expected to be) connected to the grid or its construction is abandoned (canceled or indefinitely suspended). Temporary suspension periods are included in the total construction time. Unless otherwise noted, expected startup dates are updated as of 1 January 2023.


Current Status

The status of reactors is updated as events occur or are made public. “Current Status” of reactors reflects the status known as of the latest update as indicated underneath the general map, or as of the date mentioned on the respective reactor popup.

Under Construction

The status of a reactor is “Under Construction” when:

  • Construction has started prior to or on the indicated date;

  • The reactor was not connected to the grid as of the indicated date;

  • Construction of the reactor was not cancelled or suspended as of 1 January 2023, unless otherwise noted.

The number of reactors “Under Construction” by year refers to the total number of reactors that met the “Under Construction” criteria as of December 31 of the respective year:

  • Construction of the reactor started before or during the year;

  • The reactor was not connected to the grid as of December 31 of the year;

  • Construction of the reactor was not cancelled or suspended as of December 31 of the year;

  • In case of suspension, construction resumed before or during the year.

“Behind Schedule”

“Behind Schedule” applies to reactors under construction, for which the expected startup is later than the expected startup date at construction start.


A reactor is considered Abandoned (Cancelled or Indefinitely Suspended) as of 1 January 2023 when:

  • Construction started before 1 January 2023;

  • The reactor has been declared Cancelled or Suspended (by IAEA-PRIS, operator, builder, authorities, or other knowledgeable sources) before 1 January 2023 and construction has not resumed, or

  • Construction is de facto suspended, and no active construction is underway on site with no further prospect of restart, as of 1 January 2023.

Cancelled Constructions and Indefinite Suspensions (not resumed) are grouped under the term “Abandoned” constructions.

Completed Constructions

Completed Construction applies to all reactors that have reached grid connection at some point, i.e., they are actually operating, in long-term outage (LTO), or closed.

In Operation (or Operating)

A reactor is considered in operation:

  • From the date of grid connection to the date of entering LTO status.

A reactor can be retroactively withdrawn from “In Operation” status from the day it was disconnected from the grid (either to enter the LTO status or to be considered as closed).

  • From the date of grid connection to the date of the latest power production/final disconnection from the grid;

Long-Term Outage (or LTO)

A nuclear reactor is considered in Long-Term Outage or LTO:

  • When it has not generated any electricity in the previous calendar year and in the first six months of the considered calendar year;

  • When a reactor meets these criteria, it is retroactively withdrawn from “in operation” status and enters the LTO from the day it was disconnected from the grid.


A nuclear reactor is considered as closed:

  • From the day of latest power production/final disconnection from the grid;

  • A reactor can be retroactively considered closed if it is not restarted after an outage (LTO or other).

Reactor Characteristics

Nuclear Steam Supply System (NSSS)

The Nuclear Steam Supply System (NSSS) consists of a nuclear reactor and all of the components necessary to produce high pressure steam, which is used to turn the turbine for electricity generation (IAEA-PRIS Manual). The NSSS is also called the nuclear island.

Nuclear Provider

The indicated nuclear provider is mainly based on the Nuclear Steam Supply System (NSSS) provider, as in IAEA-PRIS as of December 2020, or later for more recent constructions. In some cases, the nuclear provider has changed during construction. The WNISR database does not yet account for all of these changes. Important changes are introduced in the description of the reactor itself.


The indicated Operators are mainly based on IAEA-PRIS as of December 2020, or later in case of more recent constructions or major changes. Changes of operators are usually not identified as such.


WNISR generally uses the net electricity generating capacity as in IAEA-PRIS.

For constructions it refers to the design net capacity. The Reference Unit Power is also provided for each reactor.


This interactive visualization was developed by the core team of the World Nuclear Industry Status Report (WNISR) (data & analysis) and Visionscarto.net (design & programming), with support of the current funders of WNISR, in particular the Heinrich Böll Foundation and the Natural Resources Defense Council (NRDC).

This version is based on a first edition hosted by The Bulletin of the Atomic Scientists 2017–2020 with support from the Pulitzer Center on Crisis Reporting.


  • Julie Hazemann, Information Engineer, Director of EnerWebWatch
  • Philippe Rivière, Journalist and Programmer (visionscarto.net)
  • Mycle Schneider, Independent Analyst, Convening Lead Author and Publisher of the WNISR 
  • Arnaud Martin, Webdesigner and full-stack developer (23FORWARD)
  • Philippe Rekacewicz, Journalist and Cartographer (visionscarto.net)

For any question, remarks or corrections regarding the content of this visualization, please get in touch with contact@worldnuclearreport.org; for all technical issues please inquire with contact@visionscarto.net.