Grigory Klinishov, a key figure among the early Soviet researchers behind the two-stage thermonuclear device RDS-37, passed away in Moscow. Initial accounts, cited by Regnum from a source close to the matter, report that the 92-year-old scientist died by suicide.
The body of the engineer-physicist was discovered by relatives in his apartment on the Kosmodamianskaya Embankment in the Zamoskvorechye district. A suicide note lay beside him, in which Klinishov bade farewell to his relatives.
Later, reports from RIA Novosti and TASS confirmed the death of the scientist, according to additional sources. Regnum later provided further details, noting that the suicide occurred on June 17 but only became known four days afterward. Klinishov was deeply affected by the death of his wife and ongoing health issues. He lived with his 67-year-old daughter in the same Kosmodamianskaya Embankment residence. Shortly before his death, he spoke with his father and then left home for several hours. During that time, the physicist took his own life, and his daughter discovered the body in one of the rooms before returning home.
According to sources cited by Kommersant, the city’s Investigative Committee opened an inquiry into Klinishov’s death.
Born in 1930 in the Ryazan region, Klinishov moved with his family to Moscow during early childhood. After finishing school, he enrolled at the Moscow Mechanical Institute, today known as MEPhI, where he pursued his higher studies. Upon completing his schooling in 1956, he began work at KB-11 in the closed city of Sarov, a bureau now called the All-Russian Scientific Research Institute of Experimental Physics.
In Sarov, Klinishov served as an engineer in the theoretical department led by Andrei Sakharov, a prominent co-creator of the first Soviet atomic bomb. He earned a Doctor of Physical and Mathematical Sciences degree in 1967 and, six years later, took the helm of the theoretical department at KB-11. From 2002 onward, he held the role of lead researcher in that department.
Even at the outset of his work at KB-11, Klinishov contributed to the development of the RDS-37, the USSR’s pioneering two-stage thermonuclear device. His name appears among those who participated in the computational and theoretical studies of the weapon.
The RDS-37 underwent testing at the Semipalatinsk test site in Kazakhstan in November 1955, released from a bomber. The device’s rated explosive yield was 3 megatons, though for the test it was reduced to about 1.6 megatons. A defining distinction of this thermonuclear design was its use of a uranium-238 core and a solid lithium-6 deuteride secondary stage.
In 1955, an incident occurred during the test sequence. The Tu-16 bomber carrying the device climbed to an altitude of approximately 12 kilometers, and clouds obscured the test site. Although the crew was cleared to drop the bomb in radar sight, the aircraft declined the attempt, making a precise drop impossible. This marked the first time in nuclear testing history that a bomber aircraft had to be landed with a heavy payload in flight. Roughly 2.5 hours after takeoff, the plane finally landed at Zhana-Semey airport and was cleared for a retest two days later.
On November 22, 1955, the RDS-37 was released for retesting and detonated while on automatic parachutes, about a kilometer and a half above the ground. The bomber had managed to travel roughly 15 kilometers from the explosion point by that moment. The crew felt the blast’s thermal effects far more powerfully than anticipated. Approximately seven minutes after detonation, the radioactive mushroom cloud reached 14 kilometers in height and roughly 30 kilometers in diameter. This event marked the world’s first hydrogen bomb test with an effective yield surpassing 1 megaton.
Tragically, the consequences extended to nearby communities. In a village tens of kilometers from the test site, the ceiling of a private residence collapsed under the blast, killing a three-year-old girl. About 36 kilometers from the epicenter, six soldiers in an observation bunker were buried by soil, one of them drowning. Windows in homes within a 200-kilometer radius were shattered, and 59 settlements reported structural damage, with more than 43 people sustaining injuries in various ways.