Virginia's new correction chief yesterday ordered a massive evaluation of inmates assigned to the troubled Mecklenburg Correctional Center, the first time state officials have dealt directly with allegations that the $20 million prison is designed improperly.

"We are rethinking the concept of Mecklenburg," said Corrections Director Allyn R. Sielaff. "And this review is a part of the process."

The maximum-security prison in southern Virginia has come under harsh criticism since the death-row escapes of six inmates and a riot that demonstrated serious security and management problems at the facility, once considered one of the most modern and secure prisons on the East Coast.

The most expensive prison in the state to operate, Mecklenburg was designed to accommodate a program that many prison experts say was out of date before the facility opened. Those experts also say that Virginia's policy of housing the most aggressive and disruptive prisoners in the state at one location -- Mecklenburg -- has created an explosive and unmanageable situation.

Sielaff yesterday appeared to be dealing with those criticisms by issuing a moratorium on transferring prisoners there until a 15-member team completes a review of the facility's 263 inmates, including 27 who are on death row.

The group began reviewing the inmates' records yesterday and was expected to continue the project for about a week, said Wayne E. Farrar, a corrections department spokesman.

A large percentage of the maximum-security prisoners at Mecklenburg have been sent there because they created disciplinary problems at other prisons.

The corrections officials will be evaluating the records of all prisoners to determine whether they should remain there or be transferred to other prisons in the state, Farrar said.

Although corrections officials and state legislators have been told repeatedly that Mecklenburg is ineffective, this is the first time the state has considered a major overhaul of the prison.

Reports in The Washington Post and consultants' studies that followed disturbances at the prison this summer detailed serious flaws in the design and use of Mecklenburg.

Under the program at Mecklenburg, inmates are stripped of certain liberties that are later returned in phases if the prisoner follows regulations and is not disruptive.

Because Mecklenburg was designed as a temporary, disciplinary institution for only the most hardened inmates, it offers virtually no vocational training or long-term programs for inmates, a situation that has been criticized by the American Civil Liberties Union.

Prisons experts also have said that the modern design of the prison has backfired. A riot in which 32 inmates took nine hostages during a 19-hour siege in August was attributed partially to a design that thwarted guards' efforts to end the takeover.

Sielaff, who is the third person Robb has named to head the prison system in three years, took the job amid a flurry of announcements that he would impose major changes in the operation of the corrections department, particularly Mecklenburg.

Sielaff has ordered strict new security precautions for Mecklenburg and other prisons and said the department will hire about 30 more guards for Mecklenburg.