Chris Davenport
Technical Services Bureau
Division of Environmental Quality
Boise, ID 83706-1255

April 21, 1999

Dear Mr. Davenport,

RE: Comments for the record ISFSI NRC Docket Number 72-20

The Nuclear Regulatory Commission (NRC) issued a materials license (SNM-2508) for the Three Mile Island Unit 2 Independent Spent Fuel Storage Instillation (ISFSI) to be built at the Idaho Chemical Procession Plant (ICPP) at INEEL. The Environmental Defense Institute is on record supporting the implementation of dry spent nuclear fuel storage on the INEEL site, the issue discussed here is where on site is the appropriate location for these storage facilities.

Current knowledge of potential flooding of the ICPP was not applied to the NRC's Safety Evaluation Report of Three Mile Island Unit 2 Independent Spent Fuel Storage Instillation Safety Analysis Report (SAR) that accompanied the March 19, 1999 NRC licence. The fact that DOE is experiencing trouble finding a private entity to build and operate the ISFSI may be a blessing if it offers an opportunity to reevaluate the siting criteria.

Specifically, the NRC safety report notes at [2-7] that the "Probable Maximum Flood (PMF) on streams and rivers of the SAR, the maximum flooding at the proposed TMI-2 ISFSI will be caused by over-toping failure of the Mackey Dam through a general storm probable maximum precipitation (PMP). The ISFSI site will be at or above the maximum flood level of 4,917 ft armsl [sic] predicated for this dam failure scenario." This hydrology data is drawn from an outdated 1986 internal DOE report titled "Flood Routing analysis for a Failure of Mackey Dam" that put the peak flood flow rate at the ICPP at 66,830 cf/s. ⁽¹⁾

The US Geological Survey released a 1998 report that modeled the median 100-year flow rates in the Big Lost River down stream of the INEEL Diversion Dam (6,220 cf/s). The USGS report cross section number 22 at the ICPP puts the median flood elevation at 4,912 feet. ⁽²⁾ Again, this is only the mean flow rate (as opposed to the maximum rate of 11,600 cf/s) of just a 100 year flood, not including any additional cascading events like the failure of Mackey Dam. There are only five feet difference between the ISFSI elevation of 4,917 feet (that assumes Mackey Dam failure) and the USGS predicted elevation of 4,912 feet that does not include Mackey Dam failure. The USGS study also employed current modeling technics and plotted 37 separate cross sections on the INEEL site. The NRC report relied on an out-dated DOE study and therefore is clearly understating the flooding problem with relation to the ISFSI.

Attached is a copy of the Environmental Defense Institute report that summarizes various USGS report findings and how it applies to siting of nuclear waste facilities at the INEEL. This report clearly documents why the ICPP is not an appropriate site for nuclear waste storage or disposal.

The Environmental Defense Institute (EDI) requests that discussions with the public and regulators be implemented to review the new hydrological information and consider a different site for the ISFSI that is currently slated for the ICPP which is also in a flood plain. Additionally, EDI requests consideration of USGS's proposal for two dimensional modeling of the maximum 100-year and 500-year flow rates and the impact on INEEL facilities to enable appropriate decisions on new and existing waste facilities.

Respectfully submitted,

Chuck Broscious
Executive Director

cc:
E. William Brach, US Nuclear Regulatory Commission
Kathleen Trever, INEEL Oversight Program
Wayne Pierre, US Environmental Protection Agency

1. Flood Routing Analysis for a Failure of Mackey Dam, K. Koslow, D. Van Hafften, prepared by EG&G Idaho for U.S. Department of Energy, June 1986, EGG-EP-7184, page 26