ENS 49263
ENS Event | |
|---|---|
09:30 Aug 10, 2013 | |
| Title | Degraded Neutron Shielding for a Spent Fuel Cask |
| Event Description | {{#Wiki_filter:PPL Susquehanna, LLC became aware of a reduction in the effectiveness of a spent fuel confinement system at 0430 [EDT] on Saturday August 10, 2013. One of the safety barriers in a spent fuel cask is the water filled volume of the cask which provides neutron shielding. This volume is normally filled with approximately 670 gal of demineralized water. It has been determined that the neutron shielding volume was not completely filled. The cask neutron shield volume is currently being filled. The loaded spent fuel canister is currently located in the reactor building on the refuel floor and has been located there for the duration of the event. Investigation is currently in progress concerning personnel radiation exposure. The lack of neutron shielding represents a significant reduction in the effectiveness of a spent fuel storage cask confinement system which is an 8 hour reportable condition under 10CFR72.75(c)(2). This also represents a dry fuel storage safety system that was disabled or failed to function which is a 24 hour reportable condition under 10CFR72.75(d)(1).
The cask was a TransNuclear NUHOMS-61BTH. Personnel on the refuel floor were equipped with neutron dosimetry. The licensee notified the NRC Resident Inspector and will notify the Commonwealth of Pennsylvania.
At the time the original ENS notification was made, PPL Susquehanna, LLC had determined that a significant reduction in the effectiveness of a spent fuel storage confinement system had occurred, and that spent fuel equipment important to safety was disabled or failed to function as designed. This conclusion was reached because a loaded dry fuel storage transfer cask's neutron water shield was found partially drained down. Subsequent to this event, an investigation concluded that the identified condition is not reportable in accordance with 10 CFR 72.75(c)(2) or 10 CFR 72.75(d)(1). Transnuclear's Final Safety Analysis Report (FSAR), Chapter K.7 defines the 61BT dry fuel storage 'confinement system' as those components which make up the dry shielded cask (DSC) and not the transfer cask. Therefore, the transfer cask neutron shield is not part of the confinement system and the reporting requirements of 10 CFR 72.75(c)(2) do not apply. In addition, Transnuclear FSAR drawing number NUH-03-8002-SAR, Rev. 8, Sheet 1 'General License NUHOMS� ISFSI Onsite Transfer Cask Inner & Outer Shell Assembly' defines the neutron shield components as 'not important to safety.' Therefore, the TC neutron shield is not part of the dry fuel storage safety system and the reporting requirements of 10 CFR 72.75(d)(1) do not apply.' No personnel exposures exceeded regulatory limits. The licensee notified the NRC Resident Inspector and will notify the state. Notified the R1DO (Joustra). }}[[Event description::Description::{{#Regex_clear:PPL Susquehanna, LLC became aware of a reduction in the effectiveness of a spent fuel confinement system at 0430 [EDT] on Saturday August 10, 2013. One of the safety barriers in a spent fuel cask is the water filled volume of the cask which provides neutron shielding. This volume is normally filled with approximately 670 gal of demineralized water. It has been determined that the neutron shielding volume was not completely filled. The cask neutron shield volume is currently being filled. The loaded spent fuel canister is currently located in the reactor building on the refuel floor and has been located there for the duration of the event. Investigation is currently in progress concerning personnel radiation exposure. The lack of neutron shielding represents a significant reduction in the effectiveness of a spent fuel storage cask confinement system which is an 8 hour reportable condition under 10CFR72.75(c)(2). This also represents a dry fuel storage safety system that was disabled or failed to function which is a 24 hour reportable condition under 10CFR72.75(d)(1). The cask was a TransNuclear NUHOMS-61BTH. Personnel on the refuel floor were equipped with neutron dosimetry. The licensee notified the NRC Resident Inspector and will notify the Commonwealth of Pennsylvania.
At the time the original ENS notification was made, PPL Susquehanna, LLC had determined that a significant reduction in the effectiveness of a spent fuel storage confinement system had occurred, and that spent fuel equipment important to safety was disabled or failed to function as designed. This conclusion was reached because a loaded dry fuel storage transfer cask's neutron water shield was found partially drained down. Subsequent to this event, an investigation concluded that the identified condition is not reportable in accordance with 10 CFR 72.75(c)(2) or 10 CFR 72.75(d)(1). Transnuclear's Final Safety Analysis Report (FSAR), Chapter K.7 defines the 61BT dry fuel storage 'confinement system' as those components which make up the dry shielded cask (DSC) and not the transfer cask. Therefore, the transfer cask neutron shield is not part of the confinement system and the reporting requirements of 10 CFR 72.75(c)(2) do not apply. In addition, Transnuclear FSAR drawing number NUH-03-8002-SAR, Rev. 8, Sheet 1 'General License NUHOMS� ISFSI Onsite Transfer Cask Inner & Outer Shell Assembly' defines the neutron shield components as 'not important to safety.' Therefore, the TC neutron shield is not part of the dry fuel storage safety system and the reporting requirements of 10 CFR 72.75(d)(1) do not apply.' No personnel exposures exceeded regulatory limits. The licensee notified the NRC Resident Inspector and will notify the state. Notified the R1DO (Joustra). }}| ]] |
| Where | |
|---|---|
| Ppl Susquehanna Llc Allentown, Pennsylvania (NRC Region 1) | |
| License number: | GL |
| Organization: | Susquehanna |
| Reporting | |
| 10 CFR 72.75(c )(2), ISFSI Degradation 10 CFR 72.75(d)(1), ISFSI Safety System Functional Failure | |
| Time - Person (Reporting Time:+1.47 h0.0613 days <br />0.00875 weeks <br />0.00201 months <br />) | |
| Opened: | Doug Lamarca 10:58 Aug 10, 2013 |
| NRC Officer: | Mark Abramovitz |
| Last Updated: | Oct 3, 2013 |
| 49263 - NRC Website | |
Ppl Susquehanna Llc with 10 CFR 72.75(c)(2), ISFSI Degradation, 10 CFR 72.75(d)(1), ISFSI Safety System Functional Failure | |
WEEKMONTHYEARENS 492632013-08-10T09:30:00010 August 2013 09:30:00
[Table view]10 CFR 72.75(c)(2), ISFSI Degradation, 10 CFR 72.75(d)(1), ISFSI Safety System Functional Failure Degraded Neutron Shielding for a Spent Fuel Cask 2013-08-10T09:30:00 | |