US State Department report points to activities at China’s Lop Nur test site last year, though it does not have proof.
China may have secretly set off low-level underground nuclear test explosions despite claiming to observe an international pact banning such blasts, the US State Department said in a report on Wednesday that could fuel US-Chinese tensions.
The finding, first reported by The Wall Street Journal, may worsen ties already strained by US charges that the global Covid-19 pandemic resulted from Beijing’s mishandling of a 2019 outbreak of the coronavirus in the city of Wuhan.
US concerns about Beijing’s possible breaches of a “zero yield” standard for test blasts have been prompted by activities at China’s Lop Nur nuclear test site throughout 2019, the State Department report said.
Zero yield refers to a nuclear test in which there is no explosive chain reaction of the type ignited by the detonation of a nuclear warhead.
Jeffrey Lewis, a nuclear weapons expert at the Middlebury Institute of International Studies, said that the available evidence was possibly consistent with a low-yield tests or with “sub-critical tests”, which do not involve nuclear fission, and which are allowed by the CTBT.
“It is worth noting how thin the evidence is for these claims,” Lewis wrote. “US, Russia and China all conduct subcritical tests…From satellites and seismic stations, subcritical tests are indistinguishable from low yield nuclear tests.”
The finding may worsen ties already strained by US charges that the global Covid-19 pandemic resulted from Beijing’s mishandling of a 2019 outbreak of the coronavirus in the city of Wuhan.
The 1996 Comprehensive Test Ban Treaty (CTBT) allows activities designed to ensure the safety of nuclear weapons.
A spokeswoman for the Comprehensive Test Ban Treaty Organization, which verifies compliance with the pact, told the Wall Street Journal there had been no interruptions in data transmissions from China’s five sensor stations since the end of August 2019 following an interruption that began in 2018.
Chinese foreign ministry spokesman Zhao Lijian told a daily briefing in Beijing that China was committed to a moratorium on nuclear tests and said the United States was making false accusations.
“China has always adopted a responsible attitude, earnestly fulfilling the international obligations and promises it has assumed,” he said.
“The U.S. criticism of China is entirely groundless, without foundation, and not worth refuting.”
China, estimated to have about 300 nuclear weapons, has repeatedly rejected Trump’s proposal, arguing its nuclear force is defensive and poses no threat.