Seismic Anchorage of Dry Storage Casks


Abstract eng:
Dry storage casks (DSCs) store spent nuclear fuel (SNF) rods from nuclear power plants (NPPs). DSCs are a temporary storage solution licensed for 20 years, although they may be relicensed for operation periods up to 60 years. DSCs are being re-evaluated as a potential mid-term storage solution, where operating periods may be extended to 300 years. The potential extension of DSC compliance period increases the seismic hazard, resulting in very large horizontal accelerations and destabilizing effects from vertical accelerations. DSCs are typically unanchored, but units located in moderate to high seismic regions may slide and/or tip over, damaging the cask internals. This research focuses on the benefits of seismic anchorage of DCSs. Two types of anchorage are investigated: (a) conventional bolt details with steel chairs using designs adopted from anchoring liquid storage tanks, and (b) stretch length bolt details with steel chairs, which performed very well during the 2010 Maule, Chile earthquake. In the first phase of the study, single anchor tests are performed using both conventional and stretch length bolts under dual actuator cyclic tension and shear. The evaluated stretch lengths are equivalent to four, six and eight bar diameters. Two thicknesses are also considered for the plates of the steel chair: (i) 12.7 mm and (ii) 6.35 mm. The 6.35 mm steel plates are used to investigate the effects of allowing the steel chair to yield compared to a steel chair that remains elastic. In the second phase, a group of anchors using the steel ring to clamp the cask were tested on a 1:2.5 scaled DSC under quasi-static horizontal cyclic loads and additional tests were performed using a shake table. The experimental results are presented and compared for conventional and stretch length bolt details, as well as the scaled DCS in terms of load, displacement, and hysteretic energy capacity. It is shown that stretch length bolt anchorage details provide superior seismic performance compared to conventional bolt anchorage details.

Contributors:
Conference Title:
Conference Title:
16th World Conference on Earthquake Engineering
Conference Venue:
Santiago (CL)
Conference Dates:
2017-01-09 / 2017-01-13
Rights:
Text je chráněný podle autorského zákona č. 121/2000 Sb.



Record appears in:



 Record created 2017-01-18, last modified 2017-01-18


Original version of the author's contribution as presented on USB, paper 2205.:
Download fulltext
PDF

Rate this document:

Rate this document:
1
2
3
 
(Not yet reviewed)