ANALYSIS ON THE POTENTIAL IMPLICATIONS OF A TERRORIST ATTACK AT U.S. SPENT NUCLEAR FUEL STORAGE FACILITIES

1. ANALYSIS ON THE POTENTIAL IMPLICATIONS OF A TERRORIST ATTACK AT U.S. SPENT NUCLEAR FUEL STORAGE FACILITIES Derek Favret, Michael Stabin, Frank Parker, Jim Clarke and David Kosson

2. Introduction • September 11, 2001 • Nuclear Industry targeted • Successful attack would potentially cause devastating release of radioactive material (Source: http://en.wikipedia.org/wiki/Image:WTC_attack_9-11.jpg)

3. Headlines • “…could cause contamination problems significantly worse than those from Chernobyl” • “…could release up to 20 times the 137Cs released from Chernobyl” • “…disaster of catastrophic proportions”

4. Background Circles represent sites with one reactor, squares represent plants with two, and stars represent three. Open symbols represent sites with at least one shutdown reactor (Source: Alvarez, et al., Reducing the Hazards from Stored Spent Power-Reactor Fuel in the United States, 2003).

5. Light Water Reactors (Source: National Academies, “Safety and Security of Commercial Spent Nuclear Fuel Storage, 2006)

6. Spent Fuel Pool (SFP) • “Pool within Pool” • Building: Industrial-type design • Steel superstructure above pool • Pool depth: 12-15m • Pool volume: ~4000m3 • No drains or low-level pathways (Source: NRC, Spent Fuel Pool, 2003)

7. REALISTIC THREAT “Severe consequences and unpredictability of terrorists” National Academies: “difficult but possible” “additional analysis needed” UNREALISTIC THREAT “Robust construction and stringent security requirements” “Critics overestimate consequences and underestimate ability to cool fuel in damaged pool” Probability of Successful Attack

8. Scenario • Loss of Coolant Event – “Zirconium Fire” • “Realistic” worst-case analysis • SFP located in rural and urban areas

10. Dispersion Modeling • Defense Threat Reduction Agency • CBRNE modeling tool • Gaussian Puff model “SCIPUFF” • Joined with RASCAL and climatology database for Nuclear Reactor modeling

11. Chemical/Biological Facility Damage Chemical/Biological Weapon Industrial Facility Industrial Transportation Nuclear Weapon Nuclear Weapon Accident/Incident Radiological Weapon Incident Missile Intercept HPAC Incident Models

12. HPAC • High-resolution weather, terrain, and land cover data • Surface and Upper air climatology • Historical, real-time or forecast weather options

13. HPAC Parameters • Spent Fuel Release • Zirconium Fire • Fuel Cladding Failure • Worst-case settings • Historical Weather

14. Parameters (cont.) • Release Height – effective release height • Buoyancy • Vertical Exhaust Velocity • Temperature above Ambient (20oC) • Exhaust Area

15. RESRAD • Argonne National Lab • Calculates site-specific residual radiation levels, lifetime dose and excess lifetime cancer risks to chronically exposed on-site residents • Pathway Analysis

16. RESRAD: Pathway Analysis

17. RESRAD Scenarios

18. RESRAD Parameters • Default parameters • Radionuclides determined by HPAC • Soil density =1.5 g cm-3 • Contamination depth = 0.1 m

19. RESULTS

20. RURAL SCENARIO April, May & December yielded areas of contamination ~ 560 km2 (0.037 GBq m-2 contour) April yielded area of contamination ~ 55 km2 (0.37 GBq m-2 contour) Majority of plumes released in generally Northern direction April represents worst-case dispersion URBAN SCENARIO January yielded area of contamination ~ 202 km2 (0.037 GBq m-2 contour) January yielded area of contamination ~ 14 km2 (0.37 GBq m-2 contour) Majority of plumes released in generally Northern-Eastern direction January represents worst-case dispersion HPAC

21. Rural Scenario Ground Deposition 37 GBq m-2 3.7 GBq m-2 0.37 GBq m-2 0.037 GBq m-2 N Urban Scenario N Annual Dose Rate: 70 Sv y-1 7 Sv y-1 700 mSv y-1 70 mSv y-1

22. HPAC • Total Activity Released = 4.8E+08 GBq (13 MCi) • Radionuclides contributing to ground deposition: • 137Cs = 33.08% • 134Cs = 17.69% • 90Sr = 1.54% • 106Ru = 0.26% • 125Sb = 0.22% • 144Ce = 0.08% • 147Pm = 0.02% NOTE: (Noble Gases = 12.31%, external dose contribution only)

23. HPAC Scenarios (Mean) 137Cs = 1.48E+08 134Cs = 7.96E+07 90Sr = 7.03E+06 Chernobyl 137Cs = 8.50E+07 134Cs = 5.40E+07 90Sr = 1.00E+07 Activity Release (GBq): HPAC vs. Chernobyl

24. RESRAD: Dose Rural Scenario: 0.37 GBq m-2 (10 mCi m-2) contour

25. RESRAD: Dose Urban Scenario: 0.37 GBq m-2 (10 mCi m-2) contour

26. Protective Action Guidelines (PAG) Source: Federal Registrar, Vol 71, No. 1, 3 Jan 06

27. RESRAD: Dose Rural Scenario: 0.037 GBq m-2 (1 mCi m-2) contour

28. RESRAD: Dose Urban Scenario: 0.037 GBq m-2 (1 mCi m-2) contour

29. RESRAD: 137Cs contributions to Dose Rural Scenario: 0.037 GBq m-2 (1 mCi m-2) contour

30. RESRAD: 90Sr contributions to Dose Rural Scenario: 0.037 GBq m-2 (1 mCi m-2) contour

31. Headlines in Review • “…could cause contamination problems significantly worse than those from Chernobyl” • “…could release up to 20 times the 137Cs released from Chernobyl” • “…disaster of catastrophic proportions”

32. HPAC analysis of worst-case incident results in contamination levels in general agreement with Chernobyl. RESRAD analysis shows potential for acute effects are unlikely. Dose levels in the worst case analysis are high in some zones, showing that restrictions on worker access and temporary relocation of some populations will be necessary. Conclusions Although significant, an incident that results in a zirconium fire at a SFP may not be as catastrophic as suggested.

33. For More Information: • HPAC • http://www.dtra.mil/toolbox/directorates/td/programs/ acec/hpac.cfm • RESRAD • http://web.ead.anl.gov/resrad/home2