Koizumi says Japan not ruling out nuclear subs, days after U.S. offers positive view

Defense Minister Shinjiro Koizumi on Friday reiterated that Japan is not ruling out acquiring nuclear-powered submarines, days after a U.S. Navy official reportedly offered a positive assessment of the move.

“Regarding nuclear-powered submarines, we will proceed with our consideration of not ruling them out as an option,” Koizumi told a regular news conference. Tokyo is weighing acquiring such submarines in revisions to its three key security documents set to come by the year’s end.

Koizumi’s remarks came after an unidentified U.S. Navy official, citing Tokyo’s expertise in nuclear energy technology, told Japanese and South Korean media this week that Tokyo should consider acquiring nuclear submarines.

Asked about how the vessels might fit into Japan’s security strategy, the defense chief noted the pros and cons, saying that while nuclear-powered submarines are capable of extended patrols and are said to have several times the speed of conventionally powered submarines, they are less quiet underwater, expensive and require specialized expertise for maintenance, repair and operation.

Japan currently operates a fleet of 23 diesel-electric attack submarines, but has long avoided the more expensive and politically fraught option of nuclear-powered vessels.

Calls for Tokyo to acquire nuclear boats gained steam after an expert panel recommended in September last year that Tokyo develop vessels with “next-generation” power sources and vertical launching systems for long-range missiles. The ruling Liberal Democratic Party-Japan Innovation Party bloc effectively codified this push in their October coalition agreement.

Although neither the expert panel nor the coalition deal directly mentioned nuclear-powered submarines, Koizumi and other Japanese officials have repeatedly refused to rule out any options when it comes to nuclear submarines, as Tokyo looks to boost its defense capabilities.

Koizumi added to the speculation in November, when he touched on South Korea’s deal with the U.S. to secure nuclear vessels, noting that “all the surrounding countries have nuclear submarines.”

In June, the JIP also reignited the debate when it submitted a proposal to the government that called for the swift introduction of nuclear-powered submarines, citing China’s constant naval expansion into the Pacific.

The Chinese Navy is moving toward an all-nuclear-powered submarine fleet, U.S. naval officials say, a monumental shift that will give ammunition to proponents of Japan developing its own nuclear subs.