TS 3.3.3.3(a) requires, in part, the accident monitoring instrumentation channels shown in Table 3.3-5, including the
main steam line (
MSL) high range-noble gas effluent monitor, to be
operable. Contrary to this, on October 1, 2010, licensee evaluation of design bases for the proposed replacement of the
MSL high range-noble gas effluent monitor common to Units 3 and 4, i.e., Radiation Monitor (RAD)-6426 with Data Acquisition Monitor (DAM)-1 and High Range Noble Gas Detector Assembly SA-9, determined that the current configuration of the sample line and monitor system failed to meet the TS operability requirements. Specifically, the licensee determined that noble gas samples collected from each of the U3 and U4 steam lines would not be representative of noble gases released from the
MSL safety valves and/or atmospheric dump valves during postulated
emergency plan scenarios. Further, licensee evaluations indicated that the subject monitoring system had not met the TS requirement since it was installed in 1981. The inspectors determined that this finding is more than minor. Initial NRC concerns and licensee commitment for proposed sampling and estimating noble gas quantities released via steam pathways in accordance with
NUREG 0578 were documented in letters dated March 10, 1980, March 28, 1980, and August 20, 1980, from Robert E. Uhrig, Vice President,
Florida Power and Light to the Office of Nuclear Reactor Regulation Projects and Licensing Offices. The inspectors noted that the subject correspondence documented that subsequent to installation, operating tests were to be conducted for the purpose of correlating noble gas activities in steam samples with flow out of the system through the
MSL safety relief or atmospheric dump valves to demonstrate proper operation. However, licensee representatives stated that their reviews of monitor operability determined that neither test records nor other correlation data were found which demonstrated completion of the proposed initial operating tests for the installed monitoring system. The inspectors noted that proper oversight and review of those initial post startup tests, if conducted, potentially could have identified the design inadequacies subsequent to sample line and monitoring systems installation. Further, the
inoperable monitor had a credible impact on equipment maintained to support emergency response dose calculation capabilities in accordance with
Emergency Plan Implementing Procedure 20126, Offsite Dose Calculations. The finding was considered to have very low safety significance (Green) because the licensee had alternate methods for estimating effluent releases from the
MSL atmospheric dump and/or release valves. This issue and corrective actions were documented in the licensees corrective action program as Condition Report (CR) Numbers 572823, 585330, and 596361.
