Chernenko seen as 'sociable' and a 'work fanatic'

He can spot insincerity and does not forgive it easily. He is even-tempered, sociable but not verbose, exceptionally self-disciplined , something of a workaholic.

He favors discussion before making a decision - but rigid adherence once a decision has been made.

That's the way a longtime Soviet associate of Konstantin Chernenko describes the new Soviet leader.

His description could yield some insight into the leadership style of the man who now has the most powerful position in one of the two most powerful countries on earth.

Western Kremlinologists, however, warn of the need for caution in assessing the new Soviet leader. After all, they point out, it is unlikely that Soviet officials would paint an unflattering portrait of him. And, they add, it is too early to tell how he might carry out the duties of Communist Party leader - a post he has occupied for only a matter of days.

Nevertheless, Chernenko worked for 21 years at the Communist Party Central Committee headquarters in downtown Moscow, and another seven years as a member of the ruling Politburo of the party. During that time, he established a distinctive style in dealing with those around him.

The Soviet source, who has worked with Chernenko during a dozen of those years, asked not to be identified. He has, however, proved reliable in the past.

His description of Chernenko contrasts sharply with that of some Western analysts, who have characterized the new Soviet leader as little more than an aide and traveling companion to the late Leonid Brezhnev as the former premier forged ''detente'' with the West.

On the contrary, says this Soviet source, Chernenko ''played an important role when Leonid Brezhnev was here - and while Yuri Vladimirovich (Andropov) was here. He played an important role in the formulation of all the policies that led to detente.''

''It's not accidental,'' he continued, ''that he was present when the Helsinki Final Act was signed and when SALT II (strategic arms limitation talks) was signed. It was the physical embodiment of his important involvement in these policies.''

Chernenko, he says, is ''very well balanced, and not inclined to emotional outbursts.''

''He is a very sociable person,'' he adds, who allows ''easy access'' for consultation and discussion.

During discussions, however, the source says, ''he is not very verbose. He knows how to listen to other people.''

In turn, however, Chernenko ''expects to be listened to seriously - and with the will to understand what he is saying.''

On the other hand, he says, Chernenko ''does not stand for insincerity among the people he works with.''

Using a quintessentially Russian turn of phrase, he says Chernenko does not get along well with people who are like barrels with false bottoms.

Chernenko, he says, wants to know what his associates genuinely believe - even if it does not square with his own opinions.

''If he once feels any insincerity, or that a person is in any way insidious, that creates a certain psychological barrier with him.

''He is touchy in this sense.''

Chernenko is also a ''work fanatic,'' putting in extraordinarily long hours on party affairs - a trait which, the source says, Chernenko shared with Leonid Brezhnev: ''They are alike in this respect.''

Further, he says, Chernenko is not one to delegate important decisions. But before making them himself, the source says, Chernenko encourages discussion.

During these discussions, the Soviet associate says, ''He is open to all opinions.''

Once the decision is made, however, he says Chernenko will not stand for recriminations or second-guessing. He is, the source adds, a firm advocate of ''collective leadership,'' seeking consensus - but fully expecting support from everyone once the decision is made.

Chernenko, he says, sees this as part of ''democratic centralism,'' one of the tenets of Marxist-Leninist philosophy, especially as practiced in the Soviet Union.

''It's a matter of discipline, of ethics, with him.''