NG-04-0003, Clarification of Assumptions Regarding Reactor Building Crane
| ML040150527 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 01/07/2004 |
| From: | Peifer M Nuclear Management Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NG-04-0003 | |
| Download: ML040150527 (1) | |
Text
NM Committed to Nuclear x Duane Arnold Energy Center Operated by Nuclear Management Company, LLC January 7, 2004 NG-04-0003 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 DUANE ARNOLD ENERGY CENTER DOCKET 50-331 LICENSE NO. DPR-49
SUBJECT:
Clarification of Assumptions Regarding Reactor Building Crane
REFERENCE:
NG-01-1428, Letter dated December 21, 2001 The referenced letter provided a summary of seismic analyses regarding the Duane Arnold Energy Center (DAEC) reactor building crane. The referenced letter stated the assumption that the lifted load and lower load block are assumed decoupled from the bridge and trolley with respect to horizontal earthquake accelerations. The purpose of this letter is to provide the basis for that assumption.
The fundamental building frequency of the reactor building structure is much higher than that of the crane/hoad system. The response spectra for the building peak at a period of less than 1/3 second. An informal review of the crane/load system indicates that the shortest expected period would be greater than 3 seconds. Therefore, the horizontal seismic forces exerted on the suspended load would have no appreciable effect on the crane or the building structure.
In summary, horizontal seismic forces exerted on the crane and support structure by a lifted load are negligible. This assumption is appropriate since the period of oscillation for a suspended load is long in comparison to the response spectra of the reactor building.
This 1tter contains no new commitments.
N)
DAEC Site Vice-President cc:
Regional Administrator, USNRC, Region IlIl Project Manager (NRC-NRR)
NRC Resident Inspector (DAEC) 3277 DAEC Road
- Palo, lowa 52324-9785 Telephone: 319.851.7611