[en] Reported inaccuracies in water level instruments at nuclear power plants are being investigated by the Nuclear Regulatory Commission. In April, 1991, NRC received a report from Northeast Utilities detailing inaccuracies in a pressurized level instrument caused by accumulation of non-condensible gases in the instrument's condensing pots. The instruments measure the depth of cooling water. Further tests found a possible indication error of about plus 40%. Last month, NRC issued an information notice to all licenseeholders, saying that the problem may affect indicators at both PWRs and BWRs. The BWR Owners Group had asked the manufacturer to study the issue. Based on GE's analyses, instruments will function as designed to start the plant's safety systems when needed. GE also stated that it does not believe that this is a generic problem affecting all BWRs, saying that if there is any correction to be made, it is a configuration problem...how the instruments are laid out at a particular facility