ML072840574
| ML072840574 | |
| Person / Time | |
|---|---|
| Site: | 07200009, Fort Saint Vrain  |
| Issue date: | 09/27/2007 |
| From: | US Dept of Energy (DOE) |
| To: | Office of Nuclear Material Safety and Safeguards |
| Shared Package | |
| ML072840574 | List: |
| References | |
| TAC L24124 | |
| Download: ML072840574 (6) | |
Text
Ashtabula 2000 Proposed License Amendment Request for the Fort St. Vrain (FSV) Independent Spent Fuel Storage Installation (ISFSI)
Ashtabula 2006 Presentation to the United States Nuclear Regulatory Commission (NRC)
Rockville, MD September 27, 2007 E October 2005 M Environmental Management safety performance cleanup closure
Genesis of Need for License Amendment
Background:
- March 2004 - Licensee/contractor learn of possible installation of a new gas pipeline (FSV-04) beyond the one-half mile radius from the FSV ISFSI and its subsequent connection to the FSV meter station one mile south of the ISFSI
- Installation is not subject to the one-half mile reporting requirements of FSV ISFSI Technical Specification 5.5.3.4.a
- Concern was that the pipeline installation might never-the-less increase the design input of an existing safety analysis
- Decision was made to perform an engineering analysis of the planned pipeline installation E
M Environmental Management safety performance cleanup closure 2
Basis for License Amendment Request
- Utilization of the existing safety analysis methodology that was used by Public Service Company of Colorado is not feasible
- Largely proprietary in nature - difficult to validate
- Utilization may not produce defensible and timely analytical results
- Other concerns with existing safety analysis methodology are:
- The original safety basis evaluations were based on planned construction rather than the current as-built/as operated configuration
- Pipeline methodology was overly simplistic with overly conservative and non-conservative tradeoffs, such as:
- Depressurization calculations assumed an isothermal release which produces a non-conservative overly buoyant plume configuration, thus the plume migration/dispersion model resulted in a reduced blast load on the MVDS, however;
- The plume migration/dispersion model used an overly conservative simplification method for calculating flammable gas mass
- The blast model contained a non-bounding simplification that modeled deflagration as opposed to detonation
- DOE-ID decided to develop new safety analysis methodology E
M Environmental Management safety performance cleanup closure 3
Basis for License Amendment Request (cont.)
- DOE-ID confirmed the existing pipeline configurations (routing, diameter, and pressure) for all pipelines within one-half mile and two other significant pipelines
- New safety analysis model and methodology . . .
- Uses a more conservative adiabatic pipeline depressurization analysis
- Continues to base the plume dispersion analysis on EPA accepted dispersion equations
- Bases the plume detonation on the fuel-air explosion model appropriate for such fuel-air blasts
- Continues to compare the detonation overpressure against the Design Basis Tornado (3 psi overpressure)
- Eliminates non-conservative modeling simplifications
- Tightens overly conservative modeling simplifications
- Can be validated back to baseline equations and assumptions
- DOE plans to submit license amendment request in the mid-2008 timeframe E
M Environmental Management safety performance cleanup closure 4
Basis for License Amendment Request (cont.)
Existing/New Safety Analysis Results Comparison Distance SAR Case Existing Overpressure New Overpressure from ISFSI 3.3 psi 1.98 psi 12 FSV-02 1,400 ft (based on 875 psig (based on 740 psig maximum pre-design estimate) operation pressure) 1.3 psi 2.16 psi 24 FSV-01 4,300 ft (based on 875 psig (based on 1,003 psig pre-design estimate) maximum operating pressure) 1.04 psi 12 FSV-04 5,280 ft (based on 1,440 psig maximum allowable operating pressure)
E M Environmental Management safety performance cleanup closure 5
License Amendment Request - Preferred Outcome
- Approval to implement new pipeline safety analysis methodology
- To facilitate more timely and accurate analysis and evaluation of future natural gas and oil infrastructure changes within one-half mile radius of the FSV ISFSI and beyond, if deemed prudent
- Resultant update of gas pipeline rupture safety analyses
- Approved change to FSV ISFSI Technical Specification 5.5.3 to more accurately describe natural gas and oil infrastructure components, and make reporting requirements consistent with 10 CFR 72.48, excerpted as follows (deletions in red, additions underlined):
- 2. The database shall include an analysis of the hazard posed by failure of individual infrastructure components (such as gas wells, collector pipes, transmission pipelines, or feeder pipes production piping, production equipment, gathering pipelines, and distribution pipelines).
- 4the licensee shall submit a report
- a. within 60 days of identifying the new infrastructure if the analysis of that new infrastructure poses a hazard which exceeds that analyzed in the initial issuance of and Amendment 1 to materials License SNM 2504 requires a license amendment pursuant to 10 CFR 72.48, or
- b. otherwise with the periodic SAR update if the infrastructure poses a hazard bounded by that analyzed in the initial issuance of and Amendment No, 1 to Materials License SNM-2504 E
M Environmental Management safety performance cleanup closure 6