As increasing numbers of pundits and politicians here call for a nuclear-powered submarine to negate North Korea’s ballistic missile threats, some are questioning whether or not international treaties would allow Seoul’s use of nuclear technology for military use.

Although South Korea is a member state of the Treaty on the Non-Proliferation of Nuclear Weapons, the NPT does not appear to specifically restrict development of nuclear-powered submarines.

The NPT, which entered into force in 1970, seeks to curb non-peaceful use of nuclear technology. The aforementioned use in the treaty refers to the nuclear weapons and other nuclear explosive devices, rather than submarines.

This seems apparent in case of Brazil, which is planning to develop a nuclear-powered attack submarine, the Alvaro Alberto SN10, despite being signatory to the NPT.

The more glaring obstacle is the Seoul and Washington’s agreement on peaceful uses of nuclear energy.

It was designed to ensure that the use in Korea of nuclear technology and materials, along with cooperation between the allies, is restricted to civilian use.

Last year’s revision allowed for the enrichment up to 20 percent of uranium-235 in South Korea, on the precondition that a bilateral commission and written agreement by the US takes place. This potentially opens doors for low-level enrichment to use as nuclear fuel, but this means South Korea has to persuade the US first.

In essence, using uranium for military purposes hangs on the decision of the US.

Commercial light water reactors use “low-enriched uranium” -- which is below 20 percent concentration of uranium-235 -- and the enrichment limit for research reactor conversion is at 20 percent. Conventionally, the reactors used in nuclear submarines use uranium enriched to 20 percent or more.

While observers say that developing a nuclear submarine is possible from technological aspect, the prospect of getting US consent on a non-peaceful use of nuclear technology is uncertain.

Proponents of nuclear-powered submarines see a bright prospect of a successful negotiation, given North Korea’s strides in missile programs.

Rep. Won Yoo-chul, one of ruling Saenuri Party lawmakers who released a statement requesting a nuclear sub on Sunday, said that US will not reject the idea of Seoul having a nuclear submarine because it will help keeping North Korea in check.

The communist state has celebrated its first firing of a submarine-launched ballistic missile last week, which can theoretically strike targets up to 2,500 kilometers away and are assessed to be able to evade radars of land based missile defense systems here.

But Park Ji-young, a senior researcher of the Asan Institute for Policy Studies, pointed out that the US’ basic policy is to restrict the spread of nuclear fuels. While uranium used for fuel is not weapon-grade, she pointed out that deploying nuclear submarines can be seen as taking a step toward launching a program for developing nuclear weapons.

A scrapped nuclear submarine project during previous Roh Moo-hyun administration is an indicator of this concern.

In 2003, Roh administration pushed for a project to acquire three nuclear-powered submarines before 2020, which was canceled after it was made public.

It was rumored that rejection from the US had forced Roh to retract the plan.

By Yoon Min-sik (minsikyoon@heraldcorp.com)