05000482/FIN-2013005-03
From kanterella
Jump to navigation
Jump to search
Finding | |
|---|---|
| Title | Apparent inaccuracy in licensee dose assessment software |
| Description | The inspectors identified an Unresolved Item to determine the adequacy of licensee methods and systems for assessing the actual or potential offsite consequences of a radiological emergency, as required by 10 CFR 50.47(b)(9). The NRC determined that the licensee had identified in November 2012, a potential inaccuracy in the Electronic Dose Calculation Program (EDCP, radiological assessment software), and as of November 5, 2013, had not evaluated or corrected the inaccuracy. The NRC observed that the licensee dose assessor participating in the November 5, 2013, emergency preparedness exercise was knowledgeable about an inaccuracy in the Electronic Dose Calculation Program and subsequently reviewed Condition Report 00059832, E-Plan Drill, Potential Incorrect EDCP Dose Assessments, dated January 30, 2013. Condition Report 00059832 documented a potential inaccuracy in EDCP calculations using the main vent stack radiation monitor that was identified during an exercise conducted November 13, 2012. The main vent stack radiation monitor reports separate release rates for total Noble Gasses, radioactive Iodine, and radioactive Particulates when operating in its normal mode. In accident mode the iodine and particulate release rates are not measured. The inspectors determined the Control Room places this monitor in accident mode when the noble gas channel goes into Alert Alarm, at a value of 3530 Ci/s. When the main vent stack radiation monitor is in accident mode, EDCP compensates by calculating assumed Iodine and Particulate release rates, using a noble gas to iodine ratio; a default ratio of 10 is assumed (e.g. the iodine release rate is set to 10% of the measured noble gas release rate). Users identified during the November 13, 2012, exercise that EDCP did not appear to apply the expected noble gas to iodine ratio with the vent stack radiation monitor in accident mode. The licensee confirmed on November 7, 2013, that EDCP was not correctly applying the default noble gas to iodine ratio, resulting in an overestimate of the concentration of iodine and particulates by a factor of 10, and an overestimate of the Thyroid CDE dose. The licensee determined this deficiency existed in EDCP Version 4.7, which was in use on November 13, 2012, and continued to exist in EDCP Version 4.8, implemented October 28, 2013. The NRC continues to evaluate this issue to determine if a performance deficiency exists. No additional information is required from the licensee. URI 05000482/2013-005- 03, Apparent inaccuracy in licensee dose assessment software. |
| Site: | Wolf Creek  |
|---|---|
| Report | IR 05000482/2013005 Section 1EP5 |
| Date counted | Dec 31, 2013 (2013Q4) |
| Type: | URI: |
| cornerstone | Emergency Prep |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71114.05 |
| Inspectors (proximate) | G Guerra M Haire N Okonkwo P Elkmann R Stroblec Peabodyg Apger G George G Guerra G Ryan J Laughlin N O'Keefe N Okonkwo P Elkmann R Stroble |
| INPO aspect | |
| ' | |
Finding - Wolf Creek - IR 05000482/2013005 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Finding List (Wolf Creek) @ 2013Q4
Self-Identified List (Wolf Creek)
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||