The inspectors identified a
Severity Level IV NCV of
10 CFR 50.59 Changes, Tests, and Experiments, having very low safety significance (Green) for the licensees failure to perform an adequate safety evaluation review for changes made to the facility per modification
EC 357102. In safety evaluation BWR-E-2006-196 (for
EC 357102), the licensee failed to provide an adequate basis as to why the installation of two 15,000 gallon sulfuric acid tanks sharing a common drain system with a
sodium hypochlorite tank did not create conditions for an accident of a different type than any previously evaluated in the
Updated Final Safety Analysis Report. When these chemicals mix, they would produce an on-site release of
chlorine gas, which could potentially overcome the control room operators. The licensee entered this issue into the corrective action program and considered the control room heating, ventilation and air conditioning system
operable because of the time of year (mid-winter) such that weather conditions favoring formation of a tornado does not occur. Also, the licensee stated that the sulfuric acid tanks would be drained to approximately 2000 gallons each during the times of year when tornadoes are more likely to minimize the magnitude of any
chlorine release. Because the issue potentially impacted the NRCs ability to perform its regulatory function, this finding was evaluated using the traditional enforcement process. The finding was determined to be more than minor because the inspectors could not reasonably determine that the activity to install the new sulfuric acid tanks without detection and alarm circuits to notify the control room would not have ultimately required NRC prior approval. This finding has a cross-cutting aspect in the area of human performance because the licensee did not make appropriate or conservative decisions with respect to reviewing the plant design and license basis. Specifically, the licensee staff chose a narrow interpretation of
Regulatory Guide 1.78 Assumptions for Evaluating the Habitability of a Nuclear Power Plant Control Room During a Postulated Hazardous Chemical Release, such that a
control room habitability evaluation for an on-site
chlorine gas release was not completed. The finding was not suitable for a
significance determination process evaluation, but has been reviewed by NRC Management in accordance with qualitative criteria of
Appendix M of IMC 0609 and is determined to be a finding of very low safety significance.
