The maximum security facility at Lorton Reformatory, which houses some of the city's most dangerous convicted criminals, was described in federal court here yesterday as a "war zone" where inmates have weapons, drugs and other contraband and live in constant fear of one another.

Peter J. Nickles, an attorney representing the 400 inmates in a class-action law suit brought against the city government, told a U.S. District Court jury that the "breakdown in order" in the maximum security cell blocks has left the prisoners "under a constant threat of physical harm."

Corrections Department and other city officials, Nickles said, have "turned the key on these men in callous disregard of their humanity and committed them to this daily fight for their survival." The inmates, none of whom were in the courtroom yesterday, have asked the jury to award them money damages, contending that conditions at the high-walled prison violate their constitutional right under the 8th Amendment to be free from cruel and unusual punishment. Damages could amount to more than $10,000 per inmate.

In their lawsuit, the inmates contend that an inadequate number of guards and other staff at the maximum security facility results in an unusually high number of assaults; that prison officials do not conduct a sufficient number of "shakedowns" or searches of inmates for possession of contraband, such as weapons and that overall supervision and security is inadequate.

The jury of two women and four men heard opening statements yesterday and initial testimony from a corrections expert on behalf of the inmates. The trial, before Judge June L. Green, is expected to take about 10 days.

The inmates also want the court to order the city to increase the number of guards assigned to the maximum security facility and take whatever other measures are necessary to assure their safety.

It was the inmates' lawsuit that was first used in the federal court here two months ago as a vehicle to oppose layoffs at Lorton's maximum security facility which had been proposed as part of Mayor Marion Barry's budget cuts. Eventually, a D.C. Superior Court judge, in a separate law suit brought by correctional officers themselves, blocked all layoffs of guards at the entire Lorton complex.

Assistant D.C. Corporation Counsel Michael A. Zielinski, representing the city at yesterday's trial, told the jury in his opening statement, "We're doing the best job that we can with what's available."

Conditions at the maximum security facility are not so perilous that they amount to a violation of the inmates' constitutional rights, Zielinski argued, adding that some inmates there "will say they have never been in fear or threatened" while confined.

Nickles told the jury earlier that the inmates' "code of silence" at the maximum security facility keeps prisoners from coming forward to report the extent of assaults and abuses there.

"Punishment is punishment, but these men, these forgotten men, will tell you . . . They have lived with fear from the moment they set foot in the maximum facility," Nickles told the jury. Nickles is a partner in the Washington law firm of Covington & Burling which was appointed by the court to represent the inmates for free.

The jury also heard testimony from E. Eugene Miller, an independent corrections expert, who said that physical conditions at the facility violate minimum standards for adult correctional institutions set by a nationwide committee of corrections administrators. Miller is expected to resume testimony today.