On the 15th of December 2000 at 13:17, the last remaining operational reactor number 3 of the Chernobyl Nuclear Power Plant was shut down using the AZ-5 switch located in the reactor’s control room. This historical moment ended 23 years of the plant’s operation since September 1977.

I have received some questions regarding the AZ-5 button not causing an explosion like in the 1986 Chernobyl Disaster. Simply put, power output of the Reactor 4 was far beyond its design limits when the AZ-5 was switched on the 26.4.1986. The safety system was bypassed and all control rods removed from the reactor, so when the button was pressed with the Reactor 4 already running at dangerously high power level, all of the control rods entered the reactor chamber at once. During normal operation and with some control rods remaining in the reactor chamber, the effect of the graphite tips would not cause any serious issues beyond being registered by the monitoring equipment.

Following the Chernobyl Disaster all remaining operational RBMK-1000 reactors and their control systems were modified to prevent such thing happening again.

I couldn’t find the detailed timeline of preparations leading to the Reactor 3 shutdown until I came across a book released by the CHNPP. Hopefully the English translation below will be helpful to other people. The book contains many rare photographs of the Reactor 3 shutdown, the Chernobyl Nuclear Power Plant’s decommissioning, Chernobyl Disaster cleanup operation and a chapter about Slavutych – city located 45km from Chernobyl, erected to accommodate full-time CHNPP employees and their families after the accident.

Chernobyl NPP: CHRONICLE – 2000

In 1999, the Chernobyl NPP generated 3.319 billion kilowatt-hours of electricity, which was 102.17 percent of planned numbers (3.249 billion kilowatt-hours). The share of the Chernobyl NPP among Ukrainian NPPs amounted to 4.62 percent.

01/01/2000. The director’s order “On Core Activity of Chernobyl NPP” was issued.

20/01/2000. BK Energia held a works meeting, where the current situation, social issues and job prospects for the workforce were discussed.

20/01/2000. In the Mariyinsky Palace, Kyiv, the State Prize of Ukraine in Science and Technology was awarded to a group of Chernobyl NPP workers and residents of Slavutych. Among the award winners were general director of the plant V.K. Tolstonogov, chief specialist of the Shelter object V.H. Shcherbyna, former director of the plant M.P. Umanets, mayor of Slavutych V.P. Udovychenko, chief state sanitary doctor of the object of the Ministry of Energy M.E. Chaban.

25/01/2000. The world’s first domestic gridless centrifugal filters for cooling water purification operate at the third power unit.

08/02/2000. The director’s order was issued to establish a council for the diversification of the Chernobyl NPP.

10/02/2000. In connection with the visit of US Secretary of Energy W. Richardson to Ukraine, statements about the shutdown of the Chernobyl NPP in 2000 appeared in the media.

16/02/2000. The Verkhovna Rada of Ukraine adopted a resolution “On Holding Parliamentary Hearings in connection with Fourteenth Anniversary of Chernobyl Disaster”.

23/03/2000. The International Radioecology Laboratory was presented in Slavutych.

28—29/03/2000. Assemblies of contributors to the international Chernobyl Shelter Fund and the Nuclear Security Account were held in Slavutych.

29/03/2000. The Cabinet of Ministers of Ukraine adopted a resolution “On Early Termination of Third Power Unit Operation and Final Closure of Chernobyl NPP”.

03/04/2000. President of Ukraine Leonid Kuchma issued a decree “On Interdepartmental Commission on Complex Solution to Chernobyl NPP Problems”. The commission was appointed.

18/04/2000. Parliamentary hearings in the Verkhovna Rada of Ukraine in connection with the fourteenth anniversary of the Chernobyl disaster.

18/04/2000. The President of Ukraine created an Organizing Committee for the preparation and organization of events related to the fifteenth anniversary of the Chernobyl disaster.

25/04/2000. Working visit of Prime Minister of Ukraine V. Yushchenko to the Exclusion Zone and to the Chernobyl NPP.

25/05/2000. Working group was created at the Chernobyl NPP to determine staffing levels for the plant necessary for the optimal organization of activities related to the subsequent decommissioning of the Chernobyl NPP.

05/06/2000. During his meeting with US President Bill Clinton in Kyiv, President of Ukraine Leonid Kuchma announced the specific date of early shutdown of the third Chernobyl NPP Unit – December 15, 2000.

16/06/2000. Prime Minister of Ukraine V. Yushchenko and a delegation of the European Bank for Reconstruction and Development headed by EBRD First Vice President Charles Frank visited the Chernobyl NPP.

26/07/2000. President of Ukraine Leonid Kuchma issued a decree “On Regulations on Interdepartmental Commission on Complex Solution to Chernobyl NPP Problems”.

03/08/2000. Delegation of the Moscow Center of the World Association of Nuclear Operators (WANO) visited the Chernobyl NPP.

28—30/08/2000. Visit of Director General of the International Atomic Energy Agency (IAEA) Mohammed El-Baradei to Ukraine and the Chernobyl NPP.

14/09/2000. Visit of a team of US Department of Energy officials led by Ms Carolyn Huntoon to the Chernobyl NPP.

25/09/2000. President of Ukraine Leonid Kuchma issued a decree “On Measures related to Chernobyl NPP Closure Act”.

05/10/2000. The Verkhovna Rada of Ukraine adopted a resolution “On Holding Parliamentary Hearings on Chernobyl NPP Closure”.

19/10/2000. The President of Ukraine approved “Measures aimed at Chernobyl NPP Shutdown”.

03/11/2000. Secretary General of ISEM – international craft union – Fred Higgs held a press conference in Kyiv on the social protection of the staff of the closing Chernobyl NPP and residents of Slavutych.

16/11/2000. Workshop for Ukrainian and foreign journalists on the early decommissioning of the third power unit, the decommissioning of the plant and the transformation of the Shelter object into an ecologically safe system was held at the Chernobyl NPP.

29/11/2000. The Cabinet of Ministers of Ukraine adopted resolutions “On Final Shutdown of Chernobyl NPP”, “On Measures for Social Protection of Chernobyl NPP Workers and Residents of Slavutych in connection with Plant Closure”.

01/12/2000. Vice Prime Minister of Ukraine Y. Tymoshenko took part in the plenary session of the Atomprofspilka Central Committee held in Slavutych. The issue of social protection of Chernobyl NPP employees was considered.

04/12/2000. Visit of a group of members of parliament headed by Deputy Chairman of the Verkhovna Rada of Ukraine S. Havrysh to the Chernobyl NPP.

05/12/2000. The Verkhovna Rada of Ukraine held parliamentary hearings on the early closure of the Chernobyl NPP.

11/12/2000. First Vice Prime Minister of Ukraine Y. Yekhanurov visited the Chernobyl NPP.

14/12/2000. President of Ukraine Leonid Kuchma visited the Chernobyl NPP and the city of Slavutych. Prime Minister of Ukraine V. Yushchenko, Prime Minister of the Russian Federation M. Kasyanov, Prime Minister of Belarus V. Yermashov, ambassadors from many countries around the world arrived with him.

15/12/2000. At 13:17 by order of the President of Ukraine during the direct teleconference Chernobyl NPP – the National Palace of Arts “Ukraine”, by turning the emergency protection key (AZ-5) the reactor of the third power unit of the Chernobyl NPP was shutdown forever. The plant stopped generating electricity.

Since September 1977, the Chernobyl NPP had generated 308 billion 738 million 300 thousand kilowatt-hours of electricity.