# List of Approved Spent Fuel Storage Casks: NAC-UMS Revision 4
> **Nuclear Regulatory Commission** · Direct final rule. · Published 2005-07-25 · Effective 2005-10-11 · 70 FR 42485
## Document
- **Document number:** 05-14567
- **Category:** nuclear-waste
- **Sub-agency:** Nuclear Regulatory Commission
- **Federal Register citation:** 70 FR 42485
- **CFR reference:** 10 CFR 72
- **Publication date:** 2005-07-25
- **Effective date:** 2005-10-11
## Abstract

The Nuclear Regulatory Commission (NRC) is amending its regulations revising the NAC International, Inc., NAC-UMS Universal Storage System listing within the "List of approved spent fuel storage casks" to include Amendment No. 4 to Certificate of Compliance (CoC) Number 1015. Amendment No. 4 to the NAC-UMS CoC will modify the cask design by replacing the specific term "zircaloy" with the more generic term "zirconium alloy"; revising the definitions of "operable" and "site specific fuel"; revising vacuum drying pressure and time limits; revising short-term temperature limits and completion times for the heat removal system; clarifying the surface dose rate surveillance; adding a dissolved boron concentration option; deleting a redundant boron concentration administrative control; adding an alternate site-specific design basis earthquake analysis; and incorporating editorial and administrative changes.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2005/07/25/05-14567/list-of-approved-spent-fuel-storage-casks-nac-ums-revision-4)
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