The following violation of very low safety significance (Green) was identified by Exelon and is a violation of NRC requirements which meets the criteria of the
NRC Enforcement Policy for being dispositioned as a non-cited violation.
10 CFR 50.54(q)(2),
Emergency Plans, requires, in part, that a holder of a licensee under this part shall follow and maintain the effectiveness of an
emergency plan that meets the requirements in Appendix E to this part, and for nuclear power reactor licensees, the planning standards of 50.47(b).
10 CFR 50.47(b)(4) requires that a standard emergency classification and action level scheme, the bases of which include facility system and effluent parameters, is in use by the nuclear facility licensee. Contrary to the above, from April 25, 2016, until August 3, 2016, the spent fuel pool level emergency action level (
EAL) RG2/RS2 threshold of Limericks
Emergency Plan for a General Emergency and Site Area Emergency did not meet the requirements of Appendix E and the planning standards of
10 CFR 50.47(b). Specifically, Exelon identified that the spent fuel pool level for RG2/RS2 threshold was 0.08 feet, and the correct threshold value was 0.8 feet. The spent fuel pool
EAL threshold values for a lowering water level for an Alert and Unusual Event were correct at 10.20 feet and less than 22 feet, respectively. The normal spent fuel pool water level is over 23 feet. The inspectors evaluated this finding using
IMC 0609, Appendix B,
Emergency Preparedness Significance Determination Process, Table 5.4-1. This Table indicates, in part, that the following should be assessed as low safety significance (White): an
EAL has been rendered ineffective such that any General Emergency would not be declared for a particular off-normal event, but because of other
EALs, an appropriate declaration could be made in a degraded manner (e.g. delayed), and, an
EAL that has been rendered ineffective such that any Site Area Emergency would not be declared for a particular off-normal event. However, the inspectors confirmed that the spent fuel pool level instrumentation at
LGS goes off scale at approximately 0.635 feet, and the Limerick
Emergency Plan, in Addendum 3, directs any Emergency Director to assume the
EAL threshold has been exceeded if the associated parameter goes off scale. In addition, the NEI recommended and NRC endorsed value for this
EAL threshold would have been at nominally 0.0 feet, the level at which the fuel remains covered and actions to implement make-up water addition should no longer be deferred. Although the
LGS threshold for declaration at 0.8 feet would have been exceeded, the inspectors concluded that the event would have been classified when the
SFP level dropped below 0.635 feet, sufficiently above the NEI recommended level. Because the event would have been declared with margin to the actual water level needed for protection of the public, i.e. the spent fuel would still be fully covered by water at the time of the
EAL declaration(s), the inspectors concluded that this performance deficiency was most similar to the Table 5.4-1 branches representing very low safety significance (Green). Exelons corrective actions included revising
EP-AA-1008, Addendum 3, with the correct spent fuel pool level
EAL RG2/RS2 threshold of 0.8 feet. Because this issue was of very low safety significance (Green) and Exelon entered the issue into the corrective action program (
IR 2700440), this finding is being treated as a non-cited violation, consistent with Section 2.3.2.a of the
Enforcement Policy.
