RADIATION AND CONTAMINATION SAN ONOFRE NUCLEAR GENERATING STATIO ION COMMUNITY ENGAGEMENT PANEL MAY 28, , 2020 DR. PATRICK PAPIN DEPARTMENT OF PHYSICS GRADUATE PROGRAM IN HOMELAND SECURITY SAN DIEGO STATE UNIVERSITY 24
TOPICS OF DIS ISCUSSION • Radiation • Exposure and Contamination • Shielding • Dose Perspective • What is Safe? 25
RADIATION • Energy given off by matter in the form of rays or high- speed particles • Ionizing radiation removes electrons from atoms, causing the atoms to become electrically charged ions • Alpha particles • Beta particles • Gamma Rays • X Rays • Neutrons 26
EXPOSURE AND CONTAMINATION • Exposure • The act or condition of being subject to radiation • Minimizing exposure • Time, distance and shielding (all used SONGS) • Contamination • Radioactive material present in any substance, area, or on any surface where it is unwanted or unexpected • Dose • Absorbed energy and potential biological effects 27
SHIELDING Thick steel and concrete are used for dry storage at San Onofre 28
DOSE PERSPECTIVE 29
WHAT IS IS SAFE ? • Radiation annual dose limits • Federal occupational dose limit 5000 millirem • (Lower) SONGS worker dose limit 1500 millirem • NRC and SONGS limits for the public 100 millirem • Limits set to safe levels by NRC and recommended by various national and international agencies 1 • At these limits there is: • Nearly no chance of deterministic effects (e.g. hair loss) • Minimal risk of stochastic effects (e.g. cancer) 1 Safe levels are recommended by the National Council on Radiation Protection & Measurements and the International Commission on Radiological Protection 30
TO BE CONTINUED……. QUESTIONS? Contact Info: ppapin@sdsu.edu https://physics.sdsu.edu/ppapin/ https://homelandsecurity.sdsu.edu/ 31
Spent Fuel Design and Operating Experience Randall Granaas SCE Nuclear Fuel / ISFSI Engineer 32
Solid State Spent Nuclear Fuel Ceramic uranium dioxide fuel pellets • – Requires 5,000 degrees F to melt – Cooling since 2012 – Decay heat of SONGS hottest spent fuel assembly comparable to a hair dryer (~1500W) Sealed within corrosion-resistant • zircaloy rods (“cladding”) and pressurized with helium Organized into fuel assemblies • In dry storage, assemblies are sealed • within stainless steel canisters 33
Operating Reactors vs. SONGS Spent Fuel • Offsite releases at Chernobyl and Fukushima due to motive force associated with an operating reactor (extreme heat and steam) • Cesium-137 not volatile at dry storage temperatures (boiling point of ~1250° F) – SONGS fuel lacks the energy to volatilize cesium, not directly comparable to Chernobyl and Fukushima – No water in dry storage • Absent a motive force, radioactive contamination on the surface of the fuel, and fuel particulate, are not very mobile 34
Forced Helium Dehydrator Filter Replacement (Empirical Data) • Typical replacement of filters for FHD system • Helium at 400° F and ~80 psig circulated through canister for about 24 hours • Does not result in removal of significant quantities of radioactive material from the canister, even when drying damaged fuel • Filters are only mildly radioactive 35 35
Outlier Events and Response Strategies Expert Introductions David Victor 36
Outliers, Experts, and Perspectives Tom Isaacs SCE Experts Team Chairman, Independent Strategic Advisor for Nuclear Waste, Lead Advisor, Blue Ribbon Commission on America’s Nuclear Future 37
Criteria to Consider • Plausibility • Stakeholder interest • Human judgment, not quantitative analysis • Most experts approach in a risk-informed way • Human induced scenarios should consider role of human error or deliberate act/terrorism 38
Organizing Outliers • Naturally occurring • Human induced • Fast occurring event • Situation emerging over time 39
Organizing Outliers FAST SLOW (Occurrence) (Emergence) NATURAL Seismic / Tsunami Sea Level Rise / CISCC HUMAN Terrorism / Canister Canister Degradation (postulated crack and water Drop intrusion) 40
The Initial List • Canister drop • Corrosion and/or cracking of a canister due to chloride-induced stressed corrosion cracking (CISCC) • Groundwater daylighting • Postulated crack allows water to enter canister allowing hydrogen buildup and explosion • Sea level rise • Seismic events • Terrorist attack • Tsunami • Vibration from decommissioning and dismantlement activities 41
Defining Scenarios • Mechanistic: relates to theories that explain phenomena in purely physical or deterministic terms; by physical process alone • Postulated : defined as “assume the existence of” 42
Some Additional Thoughts • One of the biggest risks is complacency • Continuous improvement helps maintain vigilance and expectations • Earning trust and providing compelling, clear information are key • It’s also possible to create unhelpful dread and anxiety that can lead to bad decision making 43
Scenario: Postulated-crack/Water-intrusion/H2-burn Michael Corradini, Emeritus Distinguished Professor of Nuclear Engineering Engr. Physics, University of Wisconsin 44
Background • This evaluation is not mechanistic (not based on any accident analysis but analyzed for CEP discussion): – Postulated: crack allows water to enter a canister – Postulated: combustible mixture of hydrogen (H2) and oxygen (O2) in the canister due to water intrusion and radiolysis, ignition and combustion – This discussion does not imply that an H2 burn within a dry storage canister is a credible event – Consulted: Profs. Art Motta (PSU) & Joe Shepherd (CIT) • Refs: PNNL-6365, CNWRA-NRC – 02 – 07 – C – 006, 2013 45
Scenario: Postulated-crack/Water-intrusion/H2-burn Postulated Scenario Events: • Cracking of spent fuel canister • Water ingression into canister through a crack • Water radiolysis => H2 and O2 in the canister • Combustible gas (H2 and O2) builds up • Ignition and H2/O2 combustion causes pressure increase as a challenge to canister integrity 46
Scenario: Postulated-crack/Water-intrusion/H2-burn Postulated Scenario event: Cracking of Spent Fuel canister Through-wall crack of canister postulated to come from chloride- induced stress corrosion cracking (CISCC) in coastal environment • AREVA and HOLTEC systems at SONGS are 316L Stainless steel (5/8” thick) specifically for coastal environment • CISCC is a known process that develops slowly and requires specific conditions to initiate. • Inspections are done regularly for selected sets of canisters to detect any corrosion. Should any corrosion be observed, approved/proven remediation techniques would be taken. • The cracks produced would be likely plug by further oxidation or would be so small as to prevent the ingress of water. • This thru-wall crack is postulated, but is highly unlikely 47
Scenario: Postulated-crack/Water-intrusion/H2-burn Postulated Scenario events: Water ingression & water radiolysis Radiolysis of water postulated to produce a combustible mixture • Water ingress into the canister is assumed to occur without identifying source or any actions taken to preclude event • Rate of H2/O2 production from steam/water exposure is difficult to predict as it is a function of radioactive decay emissions, flux and absorption • Neglects oxygen uptake by oxidation of metallic surfaces • Time to reach a combustible mixture would take decades within the canister • Neglects the escape of H2 through the path from which water entered. 48
Scenario: Postulated-crack/Water-intrusion/H2-burn Postulated Scenario event: H2 combustion Postulate combustion of hydrogen-oxygen mixture causes a pressure rise to challenge canister integrity • No ignition source exists in the canister, but is assumed • The limiting event would be a contained combustion of a flammable mixture Given all of these conservative assumptions, analyses result in combustion pressures less than half of the design pressures for the canisters; there is no gross canister failure 49
Terrorist Kevin D. Crowley, PhD Attacks on Retired Dry ry Storage Former Senior Board Director Systems for Nuclear and Radiation Studies Board National Academies of Sciences, Spent Nucle lear Engineering, and Medicine Fuel
Dry storage system vulnerability assessments have been carried out by governments, national laboratories, nuclear industry, and independent analysts United States • Assessments of transportation cask sabotage Dry ry Storage (1970s-) (e.g., Luna et al., 1999) • Assessments following 9/11 attacks to inform System potential ISFSI security orders (2003-) Vulnerability • Assessments to support ISFSI security rulemaking, now postponed (2012-) Assessments International • Germany: Assessments to address longstanding concerns about military aircraft crashes and terrorism • Others
Assessment Topics, These assessments have improved understanding of potential vulnerabilities, but Objectives, and Availability limited information available in public domain • Aircraft attacks • Ground assaults using high-energy devices & explosives • Numerical modeling & physical experiments • Attack sequences, system containment performance, potential radioactive material releases • Most results “classified” or otherwise precluded from public disclosure; some publicly available information pulled back after 9/11 • National Academy of Sciences (NAS) reports (next slide) provide public summaries of some nonpublic assessments 52
NAS, 2006 Post-9/11 congressionally mandated review of potential vulnerabilities of dry storage systems to terrorist attacks: • Aircraft attacks • Ground assaults with high-energy devices & explosives Classified study with classified (NAS, 2004) and public (NAS, 2006) reports NAS, Post-Fukushima congressionally mandated reevaluation of NAS 2016 (2004, 2006) conclusions in light of newer information: • Classified study with public report (NAS, 2016) • Reviewed Nuclear Regulatory Commission (NRC) vulnerability assessments to support ISFSI rulemaking • NRC assessments still in progress when review completed • NAS (2016) recommended that NRC give high priority to completing assessments and ISFSI rulemaking Reports available in library 53
Example 1: : Shaped Charges • Shaped charge: Explosive device designed to focus blast energy; used for cutting hard materials • Testing of shaped charge anti-tank weapon on ductile cast iron (Castor) cask (NAS, 2006) • Bare cask breached (photo) • Cask with concrete jacket not breached • Material releases from breach of unjacketed Castor cask containing simulated fuel elements (Lange et al., 1994) • 3.6 g (1 g respirable) uranium particulates released in test • Calculated inhalation doses were < 50 mSv (5 rem) at 50 m (~160’) from cask • Note: Material releases could include gases and particulates; release quantities depend on number of damaged fuel elements and other factors 54 NAS, 2006, Figure C.4
Example 2: : Ext xternal Im Impacts • High-speed impacts on simulated overpacks for two commercially available dry storage systems (Lee et al., 2014) • Part of effort to simulate B747 aircraft engine impacts on dry storage systems • 110 lb high-strength steel slugs fired at simulated overpacks from 155 mm cannon • Slugs penetrated overpacks to different depths and deformed rear steel liners by about 2” • Test neglects some important design features of real overpacks but illustrates the robustness of dry storage systems 55 Photos from Lee et al., 2014
• Robust designs of dry storage systems help protect spent fuel from terrorist attacks Key Messages • Massive physical shielding • Multiple barriers to radioactive material releases About Dry Ab ry • No dry storage system provides complete Storage System protection against all attack types (NAS, 2006) • Any radioactive material releases from attacks Secu curity would likely be relatively small • Jet fuel fires from aircraft attacks would likely be dispersed and short duration • Effective dry storage security requires • Physically robust dry storage systems • Strong facility security to isolate dry storage systems from people and vehicles
Photo from SCE • UMAX storage is low profile, partially underground, and Key Physical protected by thick reinforced concrete pad and plugs Characteristics of f • NUHOMS storage modules are massive (~ 400,000 lbs loaded) with thick reinforced concrete shielding SONGS Dry ry • NUHOMS storage modules partially screened to oceanfront Storage Systems by UMAX ISFSI 57
• Difficult for terrorists to successfully attack dry storage systems if “success” defined by release of radioactive materials • Robust facility security ESSENTIAL for isolating stored spent fuel from people & vehicles to keep security risks low (see presentation by Dr. Clo losing Lyman) Comments • Continually assess and adjust security posture to counter newly identified threats • Continually plan for “what can go wrong” at the ISFSI and have readily deployable countermeasures available
References • Lang et al., 1994. Experimental Determination of UO2-Release from Spent Fuel Transport Cask after Shaped Charge Attack. INMM 35 th Annual Meeting Proceedings, 408 – 413. Available at https://resources.inmm.org/system/files/annual_meeting_proceedings/1994/167.pdf. • Lee et al., 2014. Impact analyses and tests of concrete overpacks of spent nuclear fuel storage casks. Nuclear Engineering and Technology 46(1), 73-80. Available at https://www.sciencedirect.com/science/article/pii/S1738573315300929. • Luna et al., 1999. Projected Source Terms for Potential Sabotage Events Related to Spent Fuel Shipments. SAND 99-0963. Available at https://www.nrc.gov/docs/ML0106/ML010650451.pdf. • NAS, 2004. Safety and Security of Commercial Spent Nuclear Fuel Storage (U): National Academies Press. • NAS, 2006. Safety and Security of Commercial Spent Nuclear Fuel Storage: Public Report. National Academies Press. Available at https://www.nap.edu/catalog/11263/safety-and- security-of-commercial-spent-nuclear-fuel-storage-public. • NAS, 2016. Lessons Learned from the Fukushima Nuclear Accident for Improving Safety and Security of U.S. Nuclear Plants: Phase 2. National Academies Press. Available at https://www.nap.edu/catalog/21874/lessons-learned-from-the-fukushima-nuclear-accident-for- improving-safety-and-security-of-us-nuclear-plants. 59
Dry cask sabotage: Outlier events Edwin S. Lyman, PhD Director of Nuclear Power Safety Union of Concerned Scientists Washington, DC 60
Security reductions at decommissioning power reactors • NRC security regulations are essentially the same for operating and decommissioning reactors • Power reactors are required to protect against the “design basis threat” of sabotage to the reactor core or spent fuel • Requires an armed response force to interdict external attackers • ISFSIs benefit from the presence of the security force although the NRC has not required that they be protected to the same level as spent fuel pools • But NRC has allowed decommissioning reactor licensees such as San Onofre to make changes to their security plans that (they assert) do not reduce their effectiveness • Eliminate annual force-on-force exercises (once all spent fuel is in the ISFSI) • Eliminate cyber security program • Also, the NRC no longer conducts triennial force-on-force inspections • As a result, spent fuel pools and ISFSIs become more vulnerable to sabotage at decommissioning plants 61
Enhancing off-site dose consequences • As Dr. Crowley has shown, sabotage attacks on dry storage casks typically have limited dose consequences • Only a small breach that limits particulate generation and release • Absence of ongoing processes that would drive enhanced radionuclide release • However, the NRC staff has identified additional modes of sabotage attack that could cause greater radionuclide releases from dry casks than previously assumed 62
NRC Draft Technical Basis for ISFSI Security Rulemaking, Revision 1 (2010) “Following the events of September 11, 2001, the NRC … evaluated several types of dry storage casks designs that were viewed as being representative of the entire population of dry storage ISFSIs... the assessments did challenge previous NRC conclusions on the ability of a malevolent act to breach shielding and/or confinement barriers and thus release radiation or radioactive material; and indicated that increased security requirements were warranted for specific scenarios such as these … In response to this new information … the NRC staff developed Commission policy paper SECY-07-0148 to update the ISFSI security requirements …” ( https://www.nrc.gov/docs/ML0932/ML093280743.pdf) 63
SECY-07-0148 (Enclosure 4), 8/2007 • However, … the [NRC] staff acknowledges that uncertainty exists on whether additional weapons capabilities may pose a vulnerability to spent fuel storage casks … an adversary's use of certain types of explosive attacks (using either manufactured or improvised devices)—which the Commission has required certain non-reactor licensees, but not ISFSIs, to defend against—may have the potential to breach some cask designs' confinement barrier and thus cause a radiological release that would exceed the 0.05-Sv (5-rem) dose limit at the ISFSI's controlled area boundary. This uncertainty has only been partially assessed by staff, but would involve, for example, adversaries using explosives to create kinetic, shear, or hydrodynamic weapons effects.” 64
S.G. Durbin and C.W. Morrow, “Analysis of Dose Consequences Arising from the Release of Spent Nuclear Fuel From Dry Storage Casks,” SAND2013-0533, January 2013 Rte. 5 65
Additional security measures • The NRC 2010 Draft Regulatory Basis proposed that if these enhanced adversary attack modes could result in unacceptable off- site dose consequences (defined as more than 5 rem), the new rule should require additional security measures for ISFSIs, such as • Increasing distance to controlled area boundary • Adding engineered security features/barriers • Shifting to a “denial” protective strategy: preventing attackers from gaining physical access to the dry storage casks 66
ISFSI security rulemaking history • 2007: The NRC approved moving forward with a rulemaking to address the new vulnerability assessment information as well as other issues • 2009: Staff issued draft regulatory basis • 2015: The NRC approved staff recommendation to delay rulemaking by five years • 2018: The NRC limited the scope of the rulemaking to codifying post-9/11 orders • 2019: Staff proposed discontinuing the rule entirely • 2020: The NRC has not issued a decision but is likely to accept the staff recommendation • The vulnerabilities first discovered 15 years ago will not be rigorously addressed • The ability of the San Onofre ISFSI to withstand enhanced adversary attack modes without causing off- site doses in excess of 5 rem is not clear 67
SONGS ISFSI-Only Security Plan Ross Quam Security Manager 68
Summary of ISFSI-Only Security • Purpose: safely protect spent fuel against radiological sabotage • Key elements: – Various types of searches can be used – Integrated intrusion detection / video surveillance system – Requirement to interdict and neutralize threats does not apply to the ISFSI; however, SCE will maintain the capability to do so in order to protect security personnel (or others) as appropriate to maintain ISFSI protection – Insider mitigation for all personnel authorized to access ISFSI – Vehicle barrier system to protect against vehicle-borne explosives – Trained on-site response force – Maintain Law Enforcement Response Plan with local law enforcement Above and beyond NRC requirements 69
SONGS Emergency Planning Kelli Gallion Sr. Manager, Emergency Planning & Preparedness 70
Our Mission To protect the health and safety of the public and our workers 71
SONGS Emergency Plan 82 • Reactors Emergency Operating Action Levels 18 • Reactors Emergency Permanently Defueled (2013) Action Levels 3 • All Spent Fuel in Emergency Dry Storage (2020) Action Levels • With all spent fuel in dry storage, there are no accident scenarios that would result in an offsite radiological release 72
SONGS Emergency Plan • Emergency Classification Levels – An operating plant has four classification levels, while decommissioned plants have two (lowest two [least severe] of the four) • Unusual Event - (Lowest emergency class) Indicates a potential problem with operation of the plant. No offsite radioactive release. Officials are notified. 1. Damage to a loaded spent fuel canister » There is no release mechanism for the contamination to go beyond the site boundary. » NUREG-1140 performed accident analyses for dry fuel storage and determined the projected dose to be 3 millirem (one-third of the dose received from a routine dental x-ray) at 100 meters from the ISFSI, which is within the SONGS boundary. 2. Security threat directed at the site • Alert -Indicates an event that could reduce the plant’s level of safety. No offsite radioactive release. Officials are notified. 73 3. Hostile Action within the ISFSI
SONGS Emergency Plan • Maintain 24/7 on-shift trained and qualified emergency responders • Maintain proficiency through required emergency response drills and training – Emergency classification and notification of offsite agencies – Radiological assessment and mitigation – Fire and Medical response with Camp Pendleton (CPEN) and agreement hospitals • Ensure prompt notification of state and local agencies (Cal OES, Orange County, San Diego OES, CPEN) – 15-minute electronic notification – 60-minute verbal notification • Maintain Written Agreements with the following Offsite Emergency Response Organizations – Camp Pendleton Fire and Medical: Firefighting, Rescue, Medical Response & Transport – Law Enforcement: State Parks, CHP, CPEN, FBI, OCSD 74 – Mission Hospital and Tri-Cities Medical Center: Treatment of contaminated, injured workers
SONGS Onsite Emergency Response Actions • The following actions will be taken in response to a damaged spent fuel canister. Let’s assume that an earthquake has been felt and validated. – On-shift emergency responders will perform radiological surveys at the ISFSI to determine if there is damage to a canister. Damage is determined by a change in radiation levels. – If damage has been determined to have occurred, then prompt notifications will be made to California Office of Emergency Services (OES), Orange County Sheriff Communications (Control One), San Diego OES, Camp Pendleton and the NRC • Electronic notification within 15-minutes • Verbal notification within 60-minutes to the 4 agencies listed above including the NRC. – Once OC has been notified, additional notifications are made to: • San Clemente, Dana Point, San Juan Capistrano and State Parks • San Clemente Emergency Management Representative notifies Capistrano Unified School District. 75
SONGS Onsite Emergency Response Actions • SCE will provide protective action recommendations to onsite personnel and offsite agencies, if applicable. • For example, if it is determined that a canister is damaged, then the Emergency Director would likely “recommend” evacuation of the state beach adjacent to SONGS. California State Parks and Camp Pendleton would assist in the relocation of those individuals • In the very unlikely event of a canister breach, on-site actions will be taken to control the spread of contamination. Typical controls include wetting, tenting/covering, ventilating and decontaminating. • The local city/county/school officials make all protective action decisions deemed necessary to protect the public. • State, federal, and local agencies will perform independent radiological monitoring around the site to independently verify radiological conditions. 76
Orange and San Diego Counties Emergency Planning & Response for Offsite Agencies May 28, 2020 Community Engagement Panel Outlier Events Workshop 77
Local Coordination • The Counties of Orange and San Diego along with local jurisdictions will maintain individual emergency response plans specific to the San Onofre Nuclear Generating Station. • Local jurisdictions will continue to support local planning, drills, and exercises for nuclear emergency planning and response. • Local jurisdictions will coordinate joint emergency planning activities through the Interjurisdictional Planning Committee. 78
Jurisdictional Emergency Plans • County and City Emergency Operations Plans – Basic Plans – Functional Annexes – Hazard-Specific Annexes and Appendices • County SONGS Specific Emergency Plan – Interjurisdictional Policies – Offsite Dose Assessment – Emergency Protective Actions – Recovery 79
Orange County • Response to an emergency at SONGS – Begins with notification of a situation • Call into Control One (24 hour warning point for Orange County or 9-1-1 – First Responders arrive & simultaneously impacted jurisdictions will be notified by Control One – Incident Commander determines response posture & public protective actions • Initial size up and protective actions will be determined • Radiological Monitoring Teams will be organized • Offsite Dose Assessment Center will be activated • County EOC may be activated to assist jurisdictions impacted and coordinate response 80
Emergency Response Actions • Key Current Procedures – Law Enforcement – Multi-Agency Coordination – Fire/Rescue – Exercises and Drills – Medical (EMS) – Decontamination – Medical/Public Health – Public Information/ – Offsite Radiological Notification Plume Monitoring – Training – Emergency Operations Center Activation 81
Alert, Warning & Notification in San Diego & Orange Counties As related to SONGS Decommissioning Stephen Rea Assistant Director County of San Diego Office of Emergency Services Stephen.rea@sdcounty.ca.gov 82
Emergency Action Levels • Current emergency plans call for Edison to notify San Diego and Orange Counties of an “Unusual Event” or “Alert” at the plant within 15 minutes of the event. 83
Multimodal Alert, Warning and Notification 84
Wireless Emergency Alerts (WEA) WEA Types: • Imminent Threat Alerts that include extreme weather, and other threatening emergencies in your area; • Public Safety Alerts that are less severe in nature than Imminent Threat Alerts; • AMBER Alerts; • Presidential Alerts during a national emergency; and • Test Messages that are opt-in messages to support state and local WEA testing 85
Public Safety Alert • An emergency may happen near the plant, members of the public could receive Public Safety messages for these types of incidents. 86
Imminent Threat Alerts • Emergency evacuation and sheltering may occur in the vicinity of the decommissioned plant • Local or State Emergency 87
Cell Tower Map 88
Outlier Events and Response Strategies Recap David Victor and Doug Bauder 89
BREAK 90
Public Comment Submit written comments to: nuccomm@songs.sce.com 91
For Internal Use Only CLOSING COMMENTS DAVID VICTOR AND DOUG BAUDER 92
For Internal Use Only For Internal Use Only 2020 CEP Meetings Planned Focus Topics 1Q CEP Meeting – Decommissioning and fuel transfer operations 2Q CEP Meeting – Outlier events and response strategies 3Q CEP Meeting* 4Q CEP Meeting* * Topics to be determined Subject to Change 93
Thank you Stay safe and healthy 94
For Internal Use Only For Internal Use Only Acronyms 95
For Internal Use Only APPENDIX 96
Initial comments Working Group • Doug Bauder - SCE VP and Chief Nuclear Officer, SONGS Decommissioning • Donna Boston - County of Orange Emergency Management • Manuel Camargo - SCE Strategic Planning & Stakeholder Engagement • Katie Day - Surfrider Foundation • John Dobken - SCE Public Information Officer • Kelli Gallion-Sholler - SCE Emergency Planning • Randall Granaas - SCE Fuels Engineering • Gary Headrick - San Clemente Green • Ace Hoffman - San Clemente Resident • Tom Isaacs - SCE Experts Team & Independent Strategic Advisor for Nuclear Waste • Roger Johnson - San Clemente Resident • Torgen Johnson – Solana Beach Resident • Jerry Kern - CEP Secretary • Stephen Rea - County of San Diego Emergency Management • Lorraine Sandstrom - SCE Community Affairs & Relations • Jerry Stephenson - SCE Manager, ISFSI Engineering • Dan Stetson - CEP Vice Chairman • David Victor - CEP Chairman 97
RADIOACTIVITY AND CONTAMINATION APPENDIX DR. PATRICK PAPIN 98
RADIOACTIVE DECAY • Half-Life (constant value) • Time required for the number of radioactive atoms to be decreased by a factor of one half • Activity (value decreases over time) • Number of decays (disintegrations) of the radioactive atom per time elapsed 99
BIO IOLOGICAL DAMAGE Absorbed Dose x RBE = Dose Equivalent • Relative Biological Effectiveness (RBE) • Beta, Gamma, X-Rays = 1 • Neutrons = 10 • Alpha = 20 • Passing radiation encounters living cells. • May destroy the cells ability to function, repair, or divide normally. • Most damage results when the radiation absorbed energy breaks chemical bonds and ionizes molecules. • Radiation (except in extreme conditions) damage is not due to heat transfer to the cell. • Example-a whole-body dose that results in a 50% chance of death only increases body temperature equivalent to one sip of tea!! 100
Recommend
More recommend
