ML17363A412
| ML17363A412 | |
| Person / Time | |
|---|---|
| Site: | Northwest Medical Isotopes |
| Issue date: | 12/29/2017 |
| From: | Northwest Medical Isotopes |
| To: | NRC/OGC |
| SECY RAS | |
| References | |
| Construction Permit Mndtry Hrg, RAS 54137, Northwest Medical Isotopes-M 50-609-CP | |
| Download: ML17363A412 (10) | |
Text
U.S. Nuclear Regulatory Commission Commission Mandatory Meeting Safety 2 Presentation January 23, 2018 Exhibit NWMI-006 11
Integrated Safety Analysis NUREG-1537, Guidelines for Preparing and Reviewing Applications for the Licensing of Non-Power Reactors, requirements
- Used integrated safety analysis (ISA) methodologies (per 10 CFR 70 Subpart H, Additional Requirements for Certain Licensees Authorized to Possess a Critical Mass of Special Nuclear Material, and NUREG-1520, Standard Review Plan for Fuel Cycle Facilities License Applications)
- Applied radiological and chemical consequence and likelihood criteria identified in the performance requirements of 10 CFR 70.61
- Designated items relied on for safety (IROFS) and established management measures to demonstrate adequate safety for the Radioisotope Production Facility (RPF)
Evaluated RPF in systematic integrated examination, including processes, equipment, structures, and personnel activities, which ensured that all relevant hazards that could result in unacceptable consequences were adequately evaluated and appropriate protective measures were identified Evaluated special nuclear material areas through development of criticality safety evaluations (CSE) to identify double contingencies controls to maintain subcriticality Exhibit NWMI-006 2
Integrated Safety Analysis Methodology RPF was evaluated using an ISA process
- Completed process hazards analysis (PHA)
- Developed quantitative risk assessments (QRA) to address events and hazards identified in PHA as requiring additional evaluation Evaluated accident sequences (qualitatively) to identify likelihood and severity using event frequencies and consequence categories consistent with regulatory guidelines Assessed each event with an adverse consequence (involving licensed material or its byproducts) for risk using a risk matrix that enables user(s) to identify unacceptable intermediate- and high-consequence risks
- Developed IROFS to prevent or mitigate consequences of events
- Reduced risks acceptable frequencies through preventive or mitigative IROFS Exhibit NWMI-006 3
Integrated Safety Analysis Methodology (continued)
Used event trees analysis (certain circumstances)
- Provided quantitative failure analysis data (failure frequencies)
- Quantitatively analyzed an event from its basic initiators to demonstrate that quantitative failure frequencies are highly unlikely under normal standard industrial conditions (i.e., no IROFS required)
Identified management measures to ensure that the IROFS failure frequency used in the analysis was preserved and IROFS are able to perform intended function(s) when needed Translation of IROFS (10 CFR 70) to technical specifications (10 CFR 50) will be developed in the Operating License Application Exhibit NWMI-006 4
Integrated Safety Analysis Results Evaluated accident sequences using both qualitative and quantitative techniques
- Most of quantitative consequence estimates are for releases to an uncontrolled area (public)
- Worker safety consequence estimates are primarily qualitative
- As facility final design matures, quantitative worker safety consequence analyses will be performed Accidents for operations with special nuclear material (including irradiated target processing, target material recycle, waste handling, and target fabrication), radioactive materials, and hazardous chemicals were analyzed Initiating events for analyzed sequences include operator error, loss of power, external events, and critical equipment malfunctions or failures Shielded and unshielded criticality accidents assumed to have high consequences to worker if not prevented Updated frequency (likelihood) and worker and public quantitative safety consequences will be provided in Operating License Application Exhibit NWMI-006 5
Preliminary Hazard Analysis Completed PHA on eight systems; Qualitative Risk Assessment Documents 107 nodes were evaluated Radioisotope Production Facility Preliminary Hazards Analysis (PHA tables ~300 pages) Radioisotope Production Facility Integrated Safety Analysis Summary Chemical Safety Process Upsets
~140 accident sequences were Process Upsets Associated with Passive Engineering Controls Leading to Accidental Criticality Accident Sequences identified for additional evaluation; Criticality Accident Sequences that Involve Uranium Entering a System 75 accident sequences were Not Intended for Uranium Service evaluated in QRAs Criticality Accident Sequences that Involve High Uranium Content in Side Waste Stream 8 QRAs were completed, covering Facility Fires and Explosions Leading to Uncontrolled Release of Fissile Material, High- and Low-Dose Radionuclides 75 accidents; one QRA addressed Radiological Accident Sequences in Confinement Boundaries chemical accidents (including Ventilation Systems)
Administratively Controlled Enrichment, Mass, Container Volume, and Interaction Limit Process Upsets Leading to Accidental Criticality Accident Sequences Receipt and Shipping Events Evaluation of Natural Phenomenon and Man-Made Events on Safety Features and Items Relied on for Safety Exhibit NWMI-006 6
MCNP Validation (ANSI/ANS 8.24 Requirement)
Monte Carlo N-Particle Transport Code: MCNP 6.1, Continuous Energy ENDF/B- VII.1 Cross-Section Define operation/process to identify range of parameters to be validated 92 criticality safety experiments were selected that adequately match uranium enrichment, geometry, moderator, reflector, and neutron energy Define area of applicability (AoA) of the validation Analyzed data
- Determined bias and bias uncertainty
- Identified trends in data No trends were identified
- Test for normal or other distribution and select statistical method for data treatment
- Identify and support subcritical margin - Margin of subcriticality (MoS) of 0.05 k
- Calculate USL - 0.9240 Exhibit NWMI-006 7
Criticality Analysis Used first principles as bases for equipment Criticality Safety Evaluation Documents design and process area layouts Irradiated Target Handling and Disassembly Irradiated Low-Enriched Uranium Target Dissolution
- Geometry constraints (e.g., pencil tank diameters)
Molybdenum-99 Recovery
- Tank array spacing (conservative)
Low-Enriched Uranium Target Material Production
- Transition from safe-geometry process equipment Target Fabrication Uranium Solution Processes to less-restricted waste staging and processing Target Finishing equipment was considered Target and Can Storage and Carts Evaluations and analysis Hot Cell Uranium Purification Liquid Waste Processing
- MCNP code validation and upper subcritical limits for Solid Waste Collection, Encapsulation, and Staging all areas of applicability
- Defined operation/process to identify range of parameters Offgas and Ventilation
- 92 criticality safety experiments Target Transport Cask and Drum Handling
- Defined area of applicability Analytical Laboratory
- Project-specific single-parameter criticality limits for Calculations U enrichment, forms, and basic geometries
- Single Parameter Subcritical Limits for 20 wt% 235U - Uranium Metal, Uranium Oxide, and Homogenous Water Mixtures Criticality safety evaluations (CSE)
- Irradiated Target Low-Enriched Uranium Material Dissolution
- 55-Gallon Drum Arrays
- Normal operating conditions described
- Single Parameter Subcritical Limits for 20 wt% 235U -
- Criticality hazard evaluation Low-Enriched Uranium Target Material
- Target Fabrication Tanks, Wet Processes, and Storage
- Contingency analysis
- Tank Hot Cell
- Double contingency controls Exhibit NWMI-006 8
Accident Sequences Evaluated and Organization Accident Sequences Evaluated Accident-Initiating Events
- Spill and Spray Accidents - Radiological - Criticality accident and Criticality (Section 13.2.2)
- Loss of electrical power
- Dissolver Offgas Accidents --
- External events (meteorological, Radiological (Section 13.2.3) seismic, fire, flood)
- Leaks into Auxiliary Systems -
- Critical equipment malfunction Radiological and Criticality (Section 13.2.4) - Operator error
- Loss of Electrical Power Accidents - Facility fire (including explosion)
(Section 13.2.5) - Any other event potentially related to
- Natural Phenomena Accidents unique facility operations (Section 13.2.6)
- Other Accidents (Section 13.2.7)
- Accidents with Hazardous Chemicals (Section 13.3)
Exhibit NWMI-006 9
Questions?
Exhibit NWMI-006 10