ASHINGTON, Nov. 19 — In a confidential report, the nuclear industry's internal oversight group has warned utilities that a focus on production over safety had endangered an Ohio reactor and could be a broader problem around the nation.

Corrosion at the Ohio reactor, discovered in March, ate away 70 pounds of steel and left the reactor vessel vulnerable to rupturing. But while the physical degradation of the reactor was unique, the internal report suggested that the causes might not be. The report, not intended for distribution outside the nuclear industry, said the the First Energy Nuclear Operating Company, operators of the reactor, Davis-Besse, near Toledo, had fallen prey to "excessive focus on meeting short-term production goals" and "a lack of sensitivity to nuclear safety."

"The lessons learned from the Davis-Besse event are universal in nature and should be reviewed by all nuclear stations," said the report, by the Institute of Nuclear Power Operations, a group formed by the industry after the March 1979 accident at Three Mile Island, Pa., to share expertise and reduce the chance of further meltdowns. The report is marked "limited distribution" and is coded "Red: Immediate Attention."

For several years, outside critics have raised alarms about a deregulated power market, saying managers would cut corners to keep reactors operating when they should have been shut for maintenance. Even the chairman of the Nuclear Regulatory Commission raised that concern, in 1994.

At Davis-Besse, in Oak Harbor, about 25 miles east of Toledo, managers postponed taking the time to inspect an area on the vessel head that turned out to be corroding, and ignored warning signs that this was happening, the report said.

The industry has not publicly admitted to any worry, nor seized the Davis-Besse incident as a warning. The new report, however, recommended that each nuclear company "conduct a self-assessment to determine to what degree your organization has a healthy respect for nuclear safety and that nuclear safety is not compromised by production priorities."

The institute has a quasiregulatory function, bringing lagging reactor operators up to the industry standard as a way to head off tighter rules from the Nuclear Regulatory Commission. After the meltdown of the reactor at Three Mile Island, in March 1979, the industry created the institute to investigate problems at each plant and to issue confidential reports to the others, so they all could benefit from lessons learned. Operators of all the nation's power reactors are members of the institute, and on the intermittent occasions when its internal assessments become public, they have all been written in blunt terms. Industry executives say its pronouncements are carefully read.

This one, nine pages plus footnotes, was made available by a nuclear industry expert who is seeking to have the industry take it to heart.

A spokesman for the institute, Terry Young, said its personnel could get access to the plants, and state their findings plainly, only if everyone agreed that the findings should be kept within the industry. "We cherish that sense of trust," he said.

Mr. Young said the reports did, in fact, discuss management issues when that was relevant.

The report, dated Nov. 11, cites one failing that seems to show that Davis-Besse's operators had not learned to benefit from other failures. In a July 2001 report to members, the institute emphasized the importance of inspecting for corrosion after a less severe problem was found at a similar plant in South Carolina, Oconee. The institute said managers suffered from "isolationism."

The Oconee report was "reviewed and accepted" by management at Davis-Besse, the institute said, but managers did not perform the inspection on their own plant.

A year ago, even as the steel was being eaten away, the plant's operator was seeking permission to raise its power output by 12.9 percent above what it was licensed for when it opened in 1978.

Experts not involved in the preparation of the report said that it touched on a difficult area, determining when priorities have been put in the wrong order and people's attitudes have shifted away from safety and toward production, and that this report differed from most written by the institute because it focused on upper-level management.

"Talking about management is very sensitive for them," said Andrew C. Kadak, the former president of the Yankee Atomic Electric Company, an umbrella company for three reactors, and a professor at the Massachusetts Institute of Technology.

At the Union of Concerned Scientists, a watchdog group that is generally critical of the industry, David Lochbaum, a nuclear expert, said measuring attitudes toward safety was hard for people in the industry.

"Most of the nuclear industry's people are engineers," Mr. Lochbaum said. "They love equations, things they can measure. But safety culture isn't something you can do that on; you can't see how many feet of safety culture you have and whether you've come up shy or not."

Paul Blanch, a nuclear safety consultant, said that for "merchant" plants, the ones selling their production in deregulated markets, "their only concern is making money."

Mr. Blanch said the institute's report "hit the nail on the head."

"Production does come before safety," he said. "They've got to strike the proper balance."

An engineer at a nuclear plant that was shut for safety reasons for a time in the 1990's, who would not allow his name to be used, said the report was a shift for the institute, which began by trying to share best practices around the industry, and later on human performance, but which is now focused on leadership performance.