No findings of significance were identified. However, the inspectors questioned the basis for the licensees waterborne ground/well offsite sampling locations and corresponding compliance with the
RETS surveillance requirement specified in Chapter 12.5 of the
ODCM. Specifically, Table 12.5-1 of the
RETS, Radiological Environmental Monitoring Program, requires that quarterly ground/well waterborne samples be collected and analyzed from three sources only if likely to be affected. Waterborne sources likely to be affected are defined in Table 12.5-1 as those that are tapped for drinking or irrigation purposes in areas where the hydraulic gradient or recharge properties are suitable for contamination. The licensee has historically sampled from two offsite wells located to the south and west of the Dresden site, both south of the
Illinois River. Liquid radwaste effluents are discharged to the
Illinois River which flows in a westerly direction. As determined during the licensees most recent land use census, several residential wells of varying depths located on the northern banks of the
Illinois River downstream of the licensees liquid effluent (radwaste) discharge point are used as potable sources and/or for irrigation purposes and potentially may be affected sources if the hydraulic gradient or recharge properties are suitable. However, the technical basis for limiting the well water sampling program to the two wells historically sampled versus other offsite wells including residential wells downstream of the stations liquid effluent discharge into the
Illinois River on the northern banks of the river could not be provided by the licensee. Consequently, compliance with Table 12.5-1 of the
RETS could not be determined. As documented in issue report (IR) 532766, the licensee is contemplating plans to further evaluate Dresden site hydrologic data, including several existing hydrogeology studies, to validate its historical well sampling activities and to assess compliance with Table 12.5-1 of the
RETS. Pending the outcome of the licensees evaluation and the NRCs review of that information, this issue is categorized as an Unresolved Item (
URI 050-237/2006010-03; 050-249/2006010-03).
