Congress and two states scrutinize the relicensing process after a federal audit found problems with safety documents.

The federal relicensing system used to ensure that America's 1970s-era nuclear plants are safe for future decades is coming under fire following an audit that found key safety evaluations lacked critical documentation.

Without the documentation, regulators cannot be sure how carefully - or even if - the plants' key safety systems had been checked.

In filings last month, New York and Vermont regulators called for an overhaul of the Nuclear Regulatory Commission relicensing program before the NRC allows a plant in each of their states to operate for 20 more years.

Congress is eager to look at the relicensing question, too - as well as at other concerns such as the video showing guards asleep at a nuclear plant last year. Hearings are expected this month or next, says a staffer with the House Energy and Commerce Committee.

A half-dozen citizen groups have also filed objections, claiming the internal audit of the NRC's relicensing practices raises serious questions not only about current relicensing applications but past ones as well.

"Do we think the whole process is flawed? Yes, we do," says Richard Webster, an attorney for the Eastern Environmental Law Center in Newark, N.J. "The NRC can't document that these reviews were done properly and there are indications some weren't done well at all."

Relicensing is a crucial part of America's current energy strategy. The nation's 104 nuclear plants supply about one-fifth of the nation's electricity. If they are shut down, the US would have to replace them with new nuclear plants - or dozens of coal-fired plants, which would raise greenhouse-gas emissions.

So far, the NRC has relicensed nearly half of the nuclear plants, with another 35 under review. The agency expects some 20 more plants to apply for relicensing soon.

Concerns about the relicensing process stem from a report released last September by the NRC's internal watchdog, the Office of Inspector General. In the 13 relicensing cases it examined, the office found little evidence that NRC staff had confirmed the integrity of aging safety systems they approved. For example: 98 percent of 458 passages in audit, inspection, and safety evaluation reports failed to adequately document or support NRC conclusions.

Problems fell into two categories: "red" cases, where no specific support was found, and "yellow" cases, where support was often provided by the companies whose plants were being relicensed. In those latter cases, the report found that NRC safety evaluation language was often "identical or nearly identical" to the information that the companies had provided in the license renewal application.