TOKYO, Japan — The Japanese government is mulling the inclusion of a plan to evaluate whether the nation should acquire nuclear-powered submarines in its upcoming update to three core defense policy documents by the end of the year, government sources revealed Wednesday.
Supporters argue that acquiring nuclear-powered vessels, which can stay submerged for extended periods and cover vast distances, is crucial to bolstering Japan’s defense posture and maintaining deterrence as military activity from China expands in the Pacific region.
The proposal gained momentum in June when the Japan Innovation Party, a junior coalition partner, urged the government to pursue the swift introduction of nuclear submarines. The concept has also been raised during discussions held by an expert panel advising the government on the national security policy updates.
However, significant skepticism remains within the dominant Liberal Democratic Party (LDP), and officials plan to determine the exact wording of the security documents after further talks with the ruling coalition and advisory experts.
Unlike conventional submarines, which must periodically surface or extend air intake and exhaust pipes, nuclear-powered models do not require frequent surfacing and can remain underwater for several months. They can also achieve top speeds exceeding 50 kilometers per hour, compared to roughly 35 kph for diesel-electric models.
Furthermore, their larger build allows for the integration of long-range counterstrike missile systems.
A senior defense official highlighted the strategic advantages of the technology for naval warfare.
”(Nuclear submarines) can quickly flee after firing in order not to be hit by a counterattack,” a senior Defense Ministry official said. “They would be highly useful.”
Despite these tactical advantages, introducing nuclear submarines presents steep hurdles. Operating reactor-powered vessels would require specialized nuclear engineering personnel, while development, acquisition, and operational maintenance would severely strain the national defense budget.
The proposal also raises legal concerns regarding compliance with Japan’s Atomic Energy Basic Law, which restricts nuclear technology strictly to peaceful applications.
Given these obstacles, some prominent political figures remain doubtful that a formal review will lead to procurement.
”Even if a study is conducted, the conclusion will likely be that (nuclear submarines) are unnecessary,” a senior LDP lawmaker said.