When the federally chartered National Consumer Cooperative Bank opened its doors here three years ago, it was expected to nurture the growth and development of thousands of nonprofit, consumer-owned business collectives across the United States--ranging from corner grocery cooperatives to co-op apartment buildings.

Consumer advocate Ralph Nader lobbied for the bank as a way to renew the nation's cities. Congress bought the idea in 1978, modeling the bank after Franklin D. Roosevelt's farm credit system, which successfully helped agricultural co-ops in the Depression. Using more than $200 million from the American taxpayer as start-up money, the co-op bank was to make loans to consumer co-ops unable to get funds from regular commercial banks.

But a detailed examination of the operation of the bank shows that, to date, this federal experiment has flopped. According to the bank's records and interviews with present and former officials, this is where the taxpayers' investment has gone:

* Only about 40 percent of the bank's money--about $90 million--has been disbursed to borrowers, and much of it has been criticized as risky. Federal bank examiners last year found that 54 percent of the bank's loans then were credit risks, and 25 percent were not even earning interest.

While the bank has lent to some inner-city co-ops and backed some small rural businesses, the bulk of its money has gone to fund housing co-ops, many with upper-middle-class owners. One is the now-bankrupt Town Center co-op in Southwest Washington, which is in default on an $11.3 million loan from the bank.

* The other 60 percent of the bank's money--currently $160 million--has been invested. In 1981 the money was in government securities. As a result, the Treasury was paying interest directly to the co-op bank--putting another $9 million in federal money into it.

Much of the money is invested because the bank consistently has failed to meet its loan projections. The bank's former president has said she could find only 16 credit-worthy co-ops outside the housing field.

* About $9 million a year has gone to pay the operating expenses for more than 140 employes, eight regional offices and a host of outside contractors. Bank officials announced a few weeks ago that they were cutting the regional operations and staff in half to save $1 million.

* More than $1.4 million has gone to outside law firms in the last 15 months. This includes $660,000 to Wald, Harkrader & Ross, which recently hired Richard A. Gross, who had been the bank's general counsel.

Gross, who was taken into the Wald firm as a partner, said in a recent interview that he started negotiating for the partnership last February, while he was the bank's general counsel, and continued to manage the contract and approve the bills of the Wald firm. Bank records show that in late March he approved payments to the firm totaling $160,000 for work performed in December and January, a bank official said.

Gross said there was no conflict of interest in the relationship because his superiors were fully aware that he was seeking employment at the Wald firm. In addition, Gross said that the firm did superior work and that on occasion he got the firm to reduce its fees. Lawyers at the Wald firm said they also talked with Gross' superiors to make sure the bank approved of the discussions before serious negotiations took place.

A Washington lawyer who is an expert in legal ethics has been asked by the bank to review Gross' relationships with the firm to make sure that the bank's conflict of interest rules weren't violated, bank officials said.

* About $200,000 went for a consulting contract--and legal fees to negotiate it--for the bank's former president, Carol S. Greenwald. She left last fall after the critical federal bank examiners' report.

Greenwald and the bank's acting chief executive officer, Mitchell A. Rofsky, a former Nader aide who lobbied for the bill creating the bank, declined to discuss the details of her contract. But other officials said it pays her $6,000 a month for 18 months--$108,000 total--to head a financial advisory committee. According to bank officials, that advisory committee has yet to meet.

The contract also provides Greenwald with some employe benefits, use of a secretary, free office space in the bank building and a $25,000 lump-sum payment, officials said. Thus, she will be making about $95,000 this year, compared with the $75,000 in salary and deferred compensation she earned from the bank in 1982.

In addition, a spokesman for the bank said, another $64,000 was paid to two other Washington law firms to negotiate the settlement of Greenwald's contract.

Frank Sollars, an Ohio farmer and banker who is the bank's board chairman, acknowledges that the bank has been plagued with problems. But both he and Rofsky said in recent interviews that it is too early to write the bank off as a total failure.

They cite difficult economic times, a Reagan administration attempt to abolish the bank in 1981 and the problem of meeting the congressional mandate to make both regular market rate loans and subsidized loans as factors in the bank's poor performance.

"I think the need is as great as it ever was," Sollars said in a recent interview in the bank's Dupont Circle offices. "We have the learning process behind us. I think, hope, most of our mistakes have been paid for. If you pay for all your mistakes and then close the door, that's kind of ridiculous."

He said the bank feels it has a great opportunity to make loans to health care cooperatives, and still has great demand for housing loans.

The federal examiners found that the market rate loans--many of them to housing co-ops--were almost as risky as the subsidized development loans. They blamed much of the bank's poor record on "deficiencies in organization and in the capabilities and performance of staff."

The report, received by the bank board last October, also criticized the loan files and procedures, and even questioned the bank's long-range prospects for survival.

It said the lending programs "do not provide reasonable assurance that credit extended . . . can be repaid. Neither do they offer reasonable assurance that the bank is itself progressing toward an established record of credit-worthiness to enable it to sustain itself in the nation's open, competitive money and credit markets."

The examiner's listing of 51 troubled loans is filled with references to extensions of credit to struggling co-ops, ranging from large housing projects with little equity to 40-acre strawberry patches in California. One loan to a "virtually bankrupt" health food store on the West Coast only permitted "the expansion of an already unprofitable business," the report said.

Rofsky blamed the bad examination report on the "numerical quirk" of a few large housing loans being in trouble. Sollars said the board has accepted nearly every recommendation the examiners made.

"Every problem . . . mentioned, we've had," he said. "It's been lending philosophy, it's been naive, it's been lack of talent, it's been everything."

Because of its federal charter, the bank is exempt from many federal laws, including those covering labor and employment rights and disclosure of information. For example, both the federal and private labor relations boards told employes who tried to unionize that they had no jurisdiction over the new bank.

There also have been complaints over the bank's internal policies. Ed Kirshner, who was head of housing in the subsidized loan division, said that in the fall of 1981 "it was announced as a top priority to fix up the loan files to have them ready for audit. . . . Unauthorized signatures were changed to authorized signatures. In some cases, documents were backdated.

"I was asked twice by the legal department to sign documents dated six months or a year previously. That was standard practice. It was done in a way to make the files look complete at the time." Sollars and Rofsky said they were unaware of such practices.

David Jameson, the former vice president for lending and credit, was one of the few staffers with banking experience when the bank opened for business in March, 1980.

"We were trying to start a bank from scratch," he said. " . . . We had a cadre of political types without banking experience. They were bright and dedicated, but were trying to set up a government bureaucracy that didn't relate to making loans . . . . "

Along with the classifications in its portfolio, the bank also is having problems just making loans. It projected a loan volume of $78 million for 1982, but approved only $30 million. For this year it has projected $50 million, but made only $4 million in the first quarter.

Rofsky and Sollars say the bank is studying ways to expand its market, and can meet its obligation to start paying back the government start-up money in 1990. They reject Greenwald's contention that demand is weak because there are few credit-worthy co-ops outside the housing sector.

Sollars said the faults in the bank's past are "the mutual blame" of the staff and the board of directors. He said the latest reorganization and a new president should put the bank in a position to strengthen its lending abilities.

Rofsky said the bank can succeed with more time.

"We have extremely high and difficult goals, trying to develop a co-op sector in this country because of Congress' determination that a co-op sector is beneficial," he said. "I think we're doing that."