The presidential commission investigating the accident at Three Mile Island met yesterday for the first of three days of discussions on recommendations it will make to President Carter.

One published report said the commission would recommend a moratorium on new nuclear construction, but sources inside the commission denied that such a recommendation had been made.

"We have taken what could be described as a straw vote to see if there is enough interest to have the staff draft language on a construction moratorium," one source said. "But no recommendation was voted on."

"While the presidential commission may recommend anything it wants, only Congress can legislate a moratorium on nuclear construction. What the commission can do is recommend that Congress take up the issue of a moratorium, in the hopes that such a recommendation would influence a congressional vote on a halt to nuclear construction.

Sources inside the Kemeny Commission, so called because its chairman is Dartmouth College President John G. Kemeny, said that what the 12 commissioners began to do yesterday was take up each issue on which the commission had expressed interest to see if they can agree on a recommendation to resolve the issue.

Sources have said that among the recommendations the Kemeny Commission is certain to make is that the Nuclear Regulatory Commission be reorganized to strengthen its hold on nuclear safety. One way to do this would be to strip away its power over nuclear exports and other areas that have nothing to do with nuclear safety. Another would be to put the NRC into the executive branch, out of the realm of independent regulatory agencies.

On the subject of a nuclear construction moratorium, the NRC already has said it will grant no new construction or operating permits unitl the recommendations of the Kemeny Commission on nuclear safety are presented to Carter and made public.

Twenty-five applications to the NRC for nuclear construction permits are "under construction permit review." There are 95 nuclear plants under construction, meaning they have construction permits but no licenses to operate.

Sources inside the Kemeny Commission said the only moratorium seriously discussed has been one on construction permits. One source said that while there has been some discussion of putting a halt to operating license, there is not a strong enough feeling on this issue to consider making it a recommendation.