A devastating critique of the Nuclear Regulatory Commission, which the Union of Concerned Scientists accuses of gross failure in its responsibility to ensure the safe operation of atomic power plants. Disarmingly, the UCS takes no strenuous exception to nuclear power generation as an energy option; nor does it even mention Chernobyl. In matter-of-fact fashion, the public policy organization weighs and finds wanting the NRC's performance in four main areas. To begin with, it faults the agency for refusing to address, let alone resolve, fundamental technical problems; the USC disputes the efficacy of cost/benefit analyses that frequently permit the commission to accommodate the utility industry at the potential expense of public safety. Along similar lines, the activist group taxes the NRC with a public-be-damned attitude. While it's possible to quarrel with the union's assertion that delay is not a primary goal of most intervenors, the record clearly shows the NRC treats third-party participants in license proceedings as interlopers. More's the pity, in the view of the UCS, since independent interest groups and individuals have raised issues that improved reactor safety and enhanced environmental protection. Equally disturbing for the UCS is the NRC's inconsistent enforcement of its own rules and regulations as well as federal law. Among other shortcomings, the union cites the agency's reluctance to order plant shutdowns and its obvious willingness to grant design waivers or to ignore clear dangers like seismic activity in nuclear plant environs. In addition, the UCS charges, the NRC maintains the moral equivalent of a ""fraternal relationship"" with the utility industry. A holdover from the pre-1975 era when the AEC was entrusted with the promotion as well as regulation of atomic energy, these cozy ties have led to abuses that include allowing power company officials to review draft inspection and investigation reports. Despite the hard lessons learned from accidents at Three Mile Island and elsewhere, the UCS concludes, the NRC remains irresponsibly amenable to quick-fix solutions. The concerned scientists have a relatively narrow focus that begs larger questions, e.g., whether replacement of the 100-odd nuclear plants now on line or under construction in the US with fossil-fueled installations would result in more acid rain, scarcer oil, dearer electricity, and less prosperity. Within the limits of their brief, though, they make a damning, detailed, and disquieting case.