Prime Minister Indira Gandhi said that the nuclear breakthrough was “nothing to get excited about.” But Mrs. Gandhi called on the President, V. V. Giri, to convey the news, convened a Cabinet meeting and ordered the Foreign Secretary, Kewal Singh, to notify the diplomatic representatives of the United States, the Soviet Union; Britain, France and other nations.

Mrs. Gandhi, who appeared cheerful, chatted briefly with newsmen this afternoon at New Delhi's Palam Airport where she had gone to receive the President of Senegal, Leopold Sedar Senghor.

Asked if the explosion would, raise India's prestige among developing nations, Mrs. Gandhi said: “I never bother about prestige. It is nothing to get excited about. We are firmly committed only to the peaceful uses of atomic energy.’'

Later in the day, Mrs. Gandhi publicly congratulated the scientists at a news conference with Dr. $ethna. “It is a significant achievement for them and the whole country,” Mrs. Gandhi said of the scientists. “We are proud of them. They worked hard and have done good, clean job.”

The Atomic Energy Commission said that it had carried out its “peaceful nuclear explosion experiment using an implosion device.” One Indian scientific analyst said that the implosion technique implied that India had perfected a technology more sophisticated than that used by the United States for the first atomic weapon dropped on Japan.

Use for Mining Suggested

In the implosion method, according to the analyst, several pieces of the bomb material are kept apart within a spherical container. They are brought together by a chemical explosive charge to form the crucial mass necessary for an explosion of the nuclear device,

There was no mention in today's announcement about where. the nuclear device had been exploded, but speculation centered on the northwest state of Rajasthan, which has vast desert areas. An official spokesman said after the announcement that the explosion took place at about 8 A.M. today.