WASHINGTON, April 3 (Xinhuanet) -- The United States is considering to replace its W-76 warheads, a compact, powerful hydrogen warhead designed during the Cold War, The New York Times reported Sunday.

    The W-76 warhead has been the centerpiece of the US nuclear arsenal for over two decades, carried aboard nuclear submarines that prowl the Atlantic and Pacific Oceans, but in recent months it has become the subject of a fierce debate over its reliability and its place in the nuclear arsenal, the report said.

    The government is readying a plan to spend more than 2 billion US dollars on a routine 10-year overhaul to extend the life of theaging warheads, and at the same time, some weapons scientists say the warheads have a fundamental design flaw that could cause them to explode with far less force than intended.

    The W-76, developed in the early 1970's for destroying large targets like military bases, now sits packed in clusters of up to eight atop hundreds of missiles in a dozen nuclear submarines, thereport said.

    The W-76 and its troubles were born during the Cold War, when American bomb makers sought to win the arms race with designs thatmade nuclear arms lightweight, very powerful and in some cases so small that a dozen or more could fit atop a slender missile, according to the report.

    Quoting officials and weapons experts, the report said of 5,000active warheads in the US arsenal, 1,500 are W-76's, each of whichis meant to be about seven times as powerful as the bomb that destroyed Hiroshima.

    The W-76's importance is rising as the country's nuclear force relies more on submarines and less on bombers and land-based missiles, but as the arsenal's oldest warheads age, the risk of internal rusting, material degradation, corrosion, decay and the embrittling of critical parts increases, the report said.

    The overhaul to forestall such decay is scheduled to go from 2007 to 2017, and it is expected to cost more than 2 billion dollars, according to experts who have analyzed federal budget figures.

    The report quoted federal officials as disclosing in interviewsthat the warhead is being considered for a new program that intends to replace old warheads with more reliable ones. Enditem