One version of the new 8-inch neutron atrillery shell the Army wants to produce could kill as many civilians in areas adjacent to the battlefield as the already-deployed nuclear shells it would replace, according to various government experts.

President Carter and proponents of the new neutron weapons have portrayed them as relatively "clean" because their blast and heat effects would not be as great as the nuclear shells already in Europe.

The present nuclear shells would cause civilian deaths nd injuries through blast and heat in settlements near the battlefield. Judging by radiation yield estimates by the Defense Nuclear Agency, the powerful 2-to-3-kiloton version of the neutron shell would do the same thing, over about the same radius, through slow-killing and cell-damaging doses of radiation.

The 2-to-3 kiloton shell does, however, have an advantage that its supporters have played down in the public debate over the new weapons. It would be almost twice as effective in killing enemy soldiers, inside tanks and armored troop carriers within the battlefield target area as the presently deployed nuclear shells.

Therein lies one dilemma for President Carter as he decides - probably this week - whether to approve reduction of the neutron 8-inch artillery shell and Lance missile warhead.

Carter must decide whether the added military deterrent value of the new shell is worth the political and practical problems created by its publicized radiation effects on European civilian populations possibly exposed to them.

The largest 8-inch nuclear shell now in the U.S. arsenal has a 5-to-10-kiloton radiation yield. But the planned 2-to-3-kiloton neutron shell had the radiation yield of a 20-to-30-kiloton nuclear weapon.

According to top officials at DNA, that two-to-three kiloton neutron shell would deliver radiation of 300 to 450 rads a mile from ground zero. Such levels are enough to cause radiation sickness within hours in almost all soldiers or civilians exposed. Almost half of them, according to government doctor, would die within two or three months.

Those who survved, along with others who took gradually lessening radiation doses in the next half mile out from the blast, would be subject to increasing likelihood of developing leukemia and other cancers, government doctors say.

The exact relationship between low-level radiation and long-term cancer effects has long been debated by scientists and doctors.

Questioned about the off-the-battlefield radiation caused by explosion of the proposed neutron shell, a DNA official, who helped develop the weapon, said recently, "That is not our business. We are concerned with battlefield casualties, immediate casualties . . . There is no way of claiming there will be less casualties (with the neutron shell)."

There are radiation casualties with the present weapons, he added.

The DNA official went on to say that civilians in towns a mile from a battle should not be on the streets but "in their houses and in the basement."

He said the projected 300-to-450-RAD dose would be cut "one-half to one-third inside the house. And in the basement it would be one-tenth.

Even at the one-tenth or 30-to-45-RAD level, some government doctors who have studied radiation effects on humans see some dangers. "A dose of 14 rads is not exactly recently. Weyzen manages human health studies for the Energy Research and Development Administration.

ERDA scientists developed the neutron weapons, while in another ERDA section doctors explored adverse radiation effects on humans the weapons would cause.

The DNA scientist recently said "no one is going to die" at a 150-rad dose. On the other hand, a doctor working for ERDA at Oak Ridge and specializing in radiation effects said at 150 rads, "10 per cent of those exposed will die."

Another ERDA doctor noted that studies of Japanese women who survived the atomic bombs at Hiroshima or Nagasaki showed radiation dosed of 150 rads caused an increase in breast cancers.

Studies of Marshall Islanders exposed to 14 rads of radiation from fallout of a U.S. hydrogen bomb test in 1954 showed recently that almost 20 years after the event, thyroid nodules and cancers developed in larger-than-expected numbers.

Commented one ERDA doctor, "fourteen rads is not an incidential exposure."

More recently, leukemia cases have begun turning up in ex-GI's who were exposed to low level radiation during 1957 nuclear weapons tests.

To ERDA weapons builders and Defense scientists, the level of radiation is insignificant.

As one DNA official put it recently, "On the battlefield the degree of risk (to civilians) must be balanced against the alternative." By alternative, he meant military defeat.

The 8-inch neutron artillery shell is the result of almost ten years of development as the army searched for a replacement for the current nuclear shells which were sent to Europe initially in the mid-1950s.

In the early 1970s, the Army made an effort to get new 8-inch shells with designs that offered greater security and range than the current ones. The initial cost was nearly $1 billion.

The present 8-inch nuclear shells can fire only nine miles and have no internal security systems. They also are complex and slow to load and fire.

By 1974, Congress made it clear to the Army that it would not approve new shells unless they had a new design.

In January 1975, in response to this, ERDA scientists moved to develop the neutron 8-inch shell using enhanced radiation technology learned while building the Sprint missile of the anti-ballistic missile system.

DNA officials said during a recent interview that the decision to go to neutron weapons came at the right time. The Soviets "had hardened their tanks to withstand blast and thermal" effects of the presently deployed nuclear weapons.

"You would be surprised at what little danger nuclear shells do to a mass of tanks, especially at the distances they are now deployed," one defense official said. "The most effective way now to get them is with nuclear radiation. It is virtually the only way," he added.

President Carter, according to aides, will make his decision on whether or not to go ahead with production of neutrons weapons after reviewing an ERDA-Defense Department study.

Carter aides so far see no indication the President has changed his earlier "initial," decision that production of the neutron shell and warhead is warranted.