Adm. H. G. Rickover yesterday agreed on the need for a nationwide analysis of workers' exposure to radiation at the Navy's six shipyards.

But the 77-year-old architect of the nuclear navy sharply criticized a nongovernment study claiming that workers at the Navy's Portsmouth, N.H., yards suffered more than 4 times the incidence of leukemia than the expected rate.

The study was conducted by Dr. Thomas Najarian, a blood specialist with the Boston Veterans Administration hospital, who preceded Rickover as a witness at an all-day session of the House subcommittee on health and the environment.

Najarian said that his study confirmed 10 leukemia cases and that there were "an additional 12 leukemia deaths we have not identified." The expected number of deaths for the general population would have been five.

The Boston Globe, which aided Najarian in his study, concluded in a story published last month that the overall cancer death rate among Portsmouth nuclear workers was more than twice the national average and substantially higher than that of the yards' non-nuclear employes.

In a surprise development, Dr. James Liverman, acting assistant secretary of energy, told the subcommittee late in the afternoon that his department was planning to undertake mortality studies for all 40 of its nuclear facilities around the country. At a hearing before the same subcommittee in January, Liverman had indicated that no such studies were needed.

Subcommittee Chairman Paul G. Rodgers (D-Fla.) who had earlier pushed the Department of Defense to expand its inquiries into the long-term effects of low-level radiation on servicemen who participated in 1950s nuclear weapons tests, voiced his pleasure at Liverman's new approach to the problem.

Rickover seemed of two minds when answering the subcommittee members' question. On the one hand, he said that "the field of radiation effects has been one where insufficient effort has been expended" and "an analysis on a nationwide scale is long overdue."

On the other hand, however, he criticized the Najarian-Boston Globe study, saying at one point, "I'd put discovery in quotation marks," when asked about the finding.

"I don't know if there is a problem at Portsmouth," Rickover said. "From the best scientific evidence we don't see a problem."

He criticized the Globe for refusing to turn over to the Navy the names of the dead shipyard employes that provided the basis for the newspaper's findings.

He also fired a critical aside at Najarian in speaking of sceintists who "just because they have the title doctor . . . (are) sounding off abut things they don't know anything about."

Najarian described during his testimony the difficulties he encountered from the Navy and his own employer during his personal effort to develop facts on the Portsmouth situation.

He said he began with one of his own patients with leukemia at the VA hospital who had been shipyard worker. From him, Najarian learned of others and decided he would see if there was a pattern.

When he sought information on former nuclear shipyard employes, Navy officials at Portsmouth turned him down, he said.

Late last October, on his own, he mailed questionnaires to the families of 40 former shipyard workers whose names he had obtained. Four days later, his immediate supervisor in Boston was contracted by the VA in Washington and asked about Najarian's study. Najarian was told to make it clear to all those he contacted that the VA was not supporting his work.

In mid-November, based on the fist answers to his questionnaire, Najarian decided he needed additional help. When it was clear the VA would not help him, he said he turned to the Boston Globe.

At one point he said, the Navy claimed to have studied 56,000 individuals exposed to nuclear radiation and "found that radiation workers have a lower incidence of leukemia and cancer" than the general population. Najarian called that a deceptive release, since it covered only uniformed Navy personnel who served on ships and not the shipyard workers.

Subcommittee members were critical of the Navy for its refusal to provide Najarian with the names of deceased shipyard workers. Rickover, however, said legal advice was that release of such information would violate the Privacy Act.

Several members questioned why the Navy has gone to the Department of Energy for a study of all Navy shipyard workers.

Sen. Thomas J. McIntyre (D-N.H.) told the subcommittee as the hearing begain yesterday morning that, after learning of Najarian's study, he had arranged for the Atlanta-based Center for Disease Control to undertake an inquiry at Portsmouth.

CDC, an agency of the Department of Health, Education and Welfare, had taken the lead and discovered the increased leukemia cases among ex-GIs who had participated in the 1957 nuclear weapons test nicknamed Smoky.

Dr. William H. Foege, director of CDC, told the subcommittee that his office had reviewed the Najarian-Boston Globe material and "as far as it has gone it is a good study."

McIntyre said the Navy initially balked at CDC's going to Portsmouth, and accused the Pentagon of "stonewalling."

At yesterday's hearing the Navy introduced a letter from Secretary W. Graham Claytor Jr. to HEW Secretary Joseph A. Califano Jr. which said CDC would be given "the same records at Portsmouth" that would be provided to "the independent agency selected" for the Navywide shipyard study.