ML081850355
| ML081850355 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 06/27/2008 |
| From: | Ameren Corp |
| To: | Office of Nuclear Reactor Regulation |
| Thadani, M C, NRR/DORL/LP4, 415-1476 | |
| Shared Package | |
| ML081850355 | List: |
| References | |
| GL-04-002, TAC MC4671 | |
| Download: ML081850355 (2) | |
Text
Page 1 of 2 Summary of Telephone Conference Regarding Request for Extension of Completion of Corrective Actions for NRC Generic Letter 2004-02 Callaway/AmerenUE Participants: Matt Brandes, Brian Holderness, Tom Elwood NRC (NRR) Participants: Mike Scott, Mohan Thadani, Leon Whitney Date and Time of Telecon: Wednesday, June 25, 2008, 1430 to 1450 (CDT)
Background
By letter dated June 24, 2008 (ULNRC-05521) AmerenUE submitted a request to the NRC to allow an extension of the time for completing all of the remaining corrective actions identified in response to Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors." The letter provided the basis for AmerenUE's request which would delay completion of the remaining corrective actions for Callaway Plant until December 15, 2008 (from the current commitment date of June 30, 2008).
Upon receipt of the June 24 letter, the NRC requested a telephone discussion with Callaway representatives to discuss the requested extension. The June 25, 2006 telephone conference was accordingly scheduled and conducted for this purpose.
Summary of Telephone Conference The subject telephone conference between Callaway/AmerenUE and NRC personnel was conducted from 1430 to 1450 on Wednesday, June 25, 2008. After brief introductions and a lead-off by Mohan Thadani (the NRC Project Manager for Callaway), the call was led by Michael Scott of the NRC. Mr. Scott expressed his desire to understand the basis and need for the extension requested for Callaway.
The parts of AmerenUE's June 24 letter describing what testing and actions have been completed, as well as the delay in obtaining the final report for the analyses and evaluations performed by the vendor, were briefly discussed. The similarity to Wolf Creek's request was noted too. In response to a question from Mr. Scott, Matt Brandes noted that all of the actions required for ensuring an Operable ECCS, including a suction strainer head loss that ensures adequate net positive suction head for the ECCS pumps under post-LOCA conditions have been completed. The remaining actions primarily are for completing proper documentation and revision of Callaway site design documents and procedures based on the vendor-provided analyses and test results. Mr. Brandes noted that there is significant NPSH margin at Callaway, as supported by successful chemical effects and debris bypass testing conducted in January 2008.
Mr. Scott then referred to two of the remaining actions identified in Enclosure 1 of the June 24 letter, i.e., a potential modification to the safety injection system to address downstream effects and the potential removal of the containment spray system cyclone separators based on the results of the downstream effects evaluation. Mr. Brandes noted that based on the results obtained for Page 2 of 2 the downstream effects testing performed in conjunction with the strainer head loss testing conducted last January, it is very unlikely that these modifications will be needed, as there is a large amount of margin with respect to downstream component wear.
Mr. Brandes then explained the circumstances surrounding the vendor's discovery earlier this year in which an error was identified in the design for the sump strainer now installed at Callaway. The error resulted in the size of the holes in the base plate for the strainer being smaller than they should be, thus resulting in a higher pressure drop than intended. Mr. Brandes noted that this condition was evaluated and found to be acceptable, and Tom Elwood noted that an Operability Determination was performed for this condition, which supported continued Operability of the ECCS. Mr. Brandes clarified that this determination was valid under the current licensing basis as well as the new licensing basis developed in response to GL 04-02. It was noted, however, that during the refueling outage to be conducted at Callaway this fall, a modification to replace the existing strainer support with one having the correct hole size will be completed in order to increase head margin to desired levels. It was repeated that the current configuration ensures ECCS operability with respect to the strainer issue addressed by GL 04-02, notwithstanding the modification planned for the fall refueling outage.
With regard to the requested completion date extension to December 15, 2008, Mr. Scott asked why that much time is needed. Mr. Elwood and Mr. Brandes noted that the fall refueling outage is a significant factor with regard to the availability of resources for documenting the final evaluations and completing all of the remaining activities.
Mr. Scott then concluded the call, emphasizing that based on what was described in this call and in AmerenUE's June 24 letter, it is the NRC's expectation that all of the remaining corrective actions will be completed by the completion date identified in AmerenUE's request.
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