ML17265A048
| ML17265A048 | |
| Person / Time | |
|---|---|
| Site: | Northwest Medical Isotopes |
| Issue date: | 09/18/2017 |
| From: | Haass C Northwest Medical Isotopes |
| To: | Michael Balazik Document Control Desk, Division of Policy and Rulemaking |
| Shared Package | |
| ML17265A039 | List: |
| References | |
| NWMI-LTR-2017-013 | |
| Download: ML17265A048 (8) | |
Text
September 18, 2017 NWMI-LTR-2017-013 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk 11555 Rockville Pike Washington, DC 20555 Mr. Michael Balazik Research and Test Reactors Branch A Division of Policy and Rulemaking Office of Nuclear Reactor Regulation RE: Responses to Advisory Committee on Reactor Safeguard Questions on Docket No. 50-609, Northwest Medical Isotopes, LLC, NWMI-2013-021, Construction Permit Application/or Radioisotope Production, at Meetings on June 19, 2017; July 11, 2017; and August 22 and 23,2017
References:
- 1. Northwest Medical Isotopes, LLC LetterNWMI-LTR-2015-006 to U.S. Nuclear Regulatory Commission, dated July 20, 2015, NRC Project No. 0803 - Northwest Medical Isotopes, LLC, Submittal Part 2 Construction Permit Application for a Radioisotope Production Facility" (ADAMS Accession No. ML15210All4)
- 2. Northwest Medical Isotopes, LLC Letter NWMI-LTR-2017-012 to U.S . Nuclear Regulatory Commission, dated September 8, 2017, "Docket No. 50-609, Northwest Medical Isotopes, LLC, Transmittal of Revision 3 of Chapters 1.0 through 18.0 ofNWMI-2013-021, Construction Permit Application for Radioisotope Production"
- 3. EPRI Report 1025287, Seismic Evaluation Guidance, Screening, Prioritization and Implementation Details [SPID] for the Resolution ofFukushima Near-Term Task Force Recommendation 2.1: Seismic, Electric Power Research Institute, November 27, 2012, ADAMS Accession No. ML12333Al70.
- 4. EPRI, 2013, EPRJ Ground Motion Model Review Final Report, June 3, 2013, ADAMS Accession No. ML13155A553.
Response to NRC Request for Information Pursuant to IO CFR 50.54(t) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," Docket Number 50-483, Callaway Plant Unit 1, Union Electric Company Facility Operating License NPF-30, (Letter to Document Control Desk, U .S. Nuclear Regulatory Commission), Ameren Missouri, Callaway Energy Center, Fulton, Missouri, March 28, 2014.
Dear Mr. Balazik:
Northwest Medical Isotopes, LLC (NWMI) met with the Advisory Committee on Reactor Safeguards (ACRS) on June 19, 2017; July 11, 2017; and August 22 and 23, 2017. From these meetings, NWMI updated Chapters 1.0 through 14.0 ofNWMI-2013-021, Construction Permit Application for Radioisotope Production (CPA) to Revision 3 (Reference 2). In addition, there were several questions that were formally asked and NWMI is responding formally through the submission of this letter.
Northwest Medical Isotopes, LLC I 815 NW 9th Ave, Suite 256 I Corvallis, OR 97330
Mr. Michael Balazik Page 2 The formal responses concern the following topical areas of our CPA, including evolution of the Radioisotope Production Facility (RPF) design, site grading, seismic (including structural and high frequency), and uranium metal fires . Criticality safety is addressed in NWMI-2017 -RAI-003 , Response to the US. Nuclear Regulatory Commission, Northwest Medical Isotopes, LLC - Request for Additional Information Regarding Preliminary Safety Analysis Report, Construction Permit Application, Docket No. 50-609.
- 1. Evolution of Radioisotope Production Facility Design The RPF design is completed in stages. NWMI has completed the RPF preliminary design and has initiated final design. Final design is needed to develop the Operating License Application and the construction drawings and associated facility specifications to support facility construction.
The construction document phase consists of preparing drawings and specifications to establish the requirements for construction of the facility. The construction documents describe the quality, configuration, size, and relationship of all components to be incorporated into the project.
In addition, the construction documents serve as a basis for obtaining bids from contractors and are used by contractors to obtain price quotes from subcontractors.
As part of completing the RPF final design, all supporting documentation will be finalized, which includes but is not limited to:
- Final hazards analysis and associated qualitative risk assessment
- Integrated safety analysis
- Criticality safety evaluations and associated calculations
- Criticality safety program
- Criticality accident alarm system and dose analyses
- Shielding analysis
- Fire hazards analysis
- Radiation protection program and associated procedures
- Waste management program
- Material control and accountability program and associated procedures
- Natural phenomena hazards and external events analysis
- Emergency preparedness program
- Quality assurance program
- Safeguards and security program
- 2. Seismic A probabilistic seismic hazard analysis (PSHA) was performed by the U .S. Nuclear Regulatory Commission (NRC) staff for the University of Missouri Research Reactor (MURR) site to assess the seismic safety of the reactor facility using present-day methodologies, as described in Electric Power Research Institute (EPRI) guidance (Reference 3) and NRC Regulatory Guide 1.208, Peiformance-Based Approach to Define the Site-Specific Earthquake Ground Motion. As an input, the Central Eastern United States Seismic Source Characterization (CEUS-SSC) model described in NUREG- 2115, Central and Eastern United States Seismic Source Characterization for Nuclear Facilities (2012), was used, along with the updated EPRI ground motion model (Reference 4). Consistent with the EPRI guidance (Reference 3),
all CEUS-SSC background seismic sources within a 500 kilometer (km) (310 mile [mi]) radius of the MURR site were included. In addition, the repeated large magnitude earthquake sources falling within a 1,000 km (620 mi) radius of the site were considered. For each of the CEUS-SSC sources used in the PSHA, the mid-continent version of the updated EPRI ground motion model (Reference 4) was used. The resulting base rock seismic hazard curves, together with a confirmatory site response analysis, were used to develop control point seismic hazard curves and a ground motion response spectra (GMRS) for comparison.
Mr. Michael Balazik Page 3 The purpose of the site response analysis is to determine the site amplification that will occur as a result of bedrock ground motion propagating upwards through the soil/rock column to the surface.
The seismic hazard curves were estimated at the control point, defined as the top of the weathered rock layer. The 10- 4 and 10- 5 uniform hazard response spectra were also calculated using the results of the confirmatory PSHA and site response analyses, and the GMRS was computed following the criteria in NRC Regulatory Guide 1.208. The GMRS is the performance-based site-specific ground motion response spectrum.
In addition, NWMI compared the seismic response spectrum with peak ground acceleration of 0.2 g, as used in the Callaway Nuclear Plant (Reference 5) and the MURR facility with the GMRS estimated at the control point. The GMRS is enveloped by the seismic response spectrum with peak ground acceleration of0.2 g up to about 16 hertz (Hz). The GMRS exceeds the seismic response spectrum above this frequency. Based on EPRl guidance (Reference 3), the ground motions at higher than approximately I 0 Hz frequency are not damaging to the structures, systems, and components (SSC) of a nuclear reactor, except the functional performance of components sensitive to vibration (e.g., electrical relays). If the electrical relays are fail-safe on excess vibration or loss of power, the safety function of such relays will not be compromised.
NWMI will also evaluate the dynamic analyses of RPF structural components. A static analysis will be completed during final design by using a combination of static load computations to ensure that the SSCs remain in place and intact, and a combination of existing shake table test data and existing earthquake experience will be used to ensure that the equipment functions following the earthquake. The analysis of safety-related structures may be either completed by the:
Linear-elastic response spectra method performed in accordance with ASCE 4, Seismic Design of Safety-Related Nuclear Structures, Section 3.2.3.1, and ASCE 43, Seismic Design Criteria for Structures, Systems, and Components in Nuclear Facilities, Section 3.2.2
- Linear-elastic time history method performed in accordance with ASCE 4, Section 3.2.2, and ASCE 43, Section 3.2.2 Damping - The damping values used for dynamic analysis for the structural system considered will be taken from NRC Regulatory Guide 1.61 , Damping Values for Seismic Design ofNuclear Power Plants.
Inelastic energy adsorption factors and damping values used for the analysis of nuclear safety-related structures will be selected from ASCE 43, Table 5-1 .
Modeling - Finite element models will only be used for the RPF building structures. The mesh for plate elements and member nodes will be selected to provide adequate discretization and distribution of the mass. Further, the aspect ratio of plate elements will be limited to no greater than 4: 1 to ensure accurate analysis results.
Direction of seismic loading - Three orthogonal directions of seismic loading are used in the RPF design, two horizontal and one vertical. The modal components of the dynamic analysis and the spatial components ofresponse analysis are combined as described below.
- Modal combinations - The structure of the RPF is designed to be relatively stiff, and components are combined using the complete quadratic combination method.
- Spatial component combinations - Spatial components are calculated separately and combined using the square-root-sum-of-the-squares method to determine the combined earthquake effect and resulting demands.
Mr. Michael Balazik Page4 NWMI will also define specific acceptable qualification methods in the procurement packages to demonstrate seismic qualifications. Seismic qualification of items relied on for safety (IROFS) will include three options of: (1) calculations and verification that the main structural components of the SSC can withstand the seismic loads derived from the in-structure floor response spectra at the damping value derived from Regulatory Guide 1.61 , (2) reference to available shake table testing that demonstrates the seismic capacity of the SSC or of multiple similar items, and (3) demonstration of the seismic capacity through the performance of the type of SSC in actual earthquakes.
Per NRC Regulatory Guide 1.100, Seismic Qualification ofElectrical and Active Mechanical Equipment and Functional Qualification ofActive Mechanical Equipment for Nuclear Power Plants:
- Active mechanical equipment relied on for or important to nuclear safety will be required to be seismically qualified in accordance with Regulatory Guide 1.100.
- Active electrical equipment important to or relied on for nuclear safety will be required to be seismically qualified in accordance with IEEE 344, IEEE Standardfor Seismic Qualification of Equipment for Nuclear Power Generating Stations.
Subsystems and equipment not relied on for nuclear safety but designated as a component of a seismic system per International Building Code (IBC) 2012, Chapter 17, will be required. Existing databases of past shake table tests will be used, such as the Office of Statewide Health Planning and Development database provided by the state of California. These tests have typically been done based on the ICC-ES AC156, Acceptance Criteria for Seismic Certification by Shake-Table Testing ofNonstructural Components, spectrum.
The capacity of the standard support design for overhead fixtures mounted above RPF IROFS will be checked to ensure that the supports can withstand the seismic loads derived from the floor spectra (e.g., remain stable during and after postulated earthquake effects) of the attachment floor slab. This information will be provided in the final safety analysis report as part of the Operating License Application.
The RPF seismic design will also include a check to ensure that pounding or sway impact will not occur between adjacent fixtures (e.g., rattle space). Estimates of the maximum displacement of any fixture can be derived from the appropriate floor response spectrum and an estimate of the fixture's lowest response frequency. This information will be provided as part of the Operating License Application.
Seismic recording instrumentation will be triaxial digital systems that record accelerations versus time accurately for periods between 0 and 10 seconds (sec). Recorders will have rechargeable batteries such that ifthere is a loss of power, recording will still occur. All instrumentation will be housed in appropriate weather- and creature-proofed enclosures. As a minimum, one recorder should be located in the free-field mounted on rock or competent ground generally representative of the site. In addition, at sites classified as Seismic Design Category D, E, or F, in accordance with ASCE 7, Minimum Design Loads and Associated Criteria for Buildings and Other Structures, Chapter 11, using Occupancy Category IV, recorders will be located and attached to the foundations and roofs of the RPF and in the control room. The systems will have the capability to produce motion time histories. Response spectra will be computed separately.
The purpose of the instrumentation is to (1) permit a comparison of measured responses of C-I structures and selected components with predetermined results of analyses that predict when damage might occur, (2) permit facility operators to understand the possible extent of damage within the facility immediately following an earthquake, and (3) be able to determine when an safe-shutdown earthquake event has occurred that would require the emptying of the tank(s) for inspection as specified in NFPA 59A, Standard for the Production, Storage, and Handling ofLiquefied Natural Gas, Section 4.1.3.6(c).
Mr. Michael Balazik Page 5 Seismic instrumentation for the RPF site is not an IROFS; this instrumentation provides no safety function and is therefore not "safety-related." Although the seismic recorders have no safety function, the recorders must be designed to withstand any credible level of shaking to ensi.ire that the ground motion would be recorded in the highly unlikely event of an earthquake. This capability requires verification of adequate capacity from the manufacturer (e.g., prior shake table tests of their product line), provision of adequate anchorage (e.g., manufacturer-provided anchor specifications to ensure accurate recordings),
and a check for seismic interaction hazards such as water spray or falling fixtures. With these design features , the instrumentation would be treated as if it were safety-related quality level (QL)-2. Additional information on seismic instruction will be provided as part of the Operating License Application.
- 3. Site Grading NWMI' s primary goal of proper grading design is to ensure that stormwater flows off of the RPF site in a safe, efficient manner (i.e., grading is performed to ensure proper drainage). The primary design parameter of all grading designs is to maintain positive drainage (e.g., water always has an ability to flow away from the RPF site).
NWMI will grade the RPF site by configuring the surface of the land by removing or adding earthen material to shape the land to best suit the project. NWMI understands that a good grading design integrates the natural landforms of the site with the proposed program to create an aesthetically pleasing, yet functional and cost-effective site plan. The grading of the RPF site will serve three basic purposes:
- Grading re-forms the land surface to make it compatible with the intended land use .
Subsequently, the relative elevations and gradients of streets, buildings, parking areas, and pedestrian/vehicle accesses must be mutually compatible if they are to function as a system.
Similarly, these areas must be compatible with the surrounding existing terrain.
- Grading establishes and controls the new drainage patterns. To be cost-effective, the grading design should allow for the efficient collection, conveyance, and detention of stormwater runoff.
Proper grading will mitigate or prevent water damage to underground structures and the site (e.g.,
areas below ground surface, foundation damage, eroding hillsides, and muddy stream waters).
Grading helps define the character and aesthetics of the site. Site design is the foundation on which many other elements of site development depend. Proper grading should be cost-effective and responsive to the opportunities and restraints offered by the site.
NWMI will consider both the runoff that starts on the site and the runoff that flows onto the site from off-site areas. The drainage analysis will serve as the basis for the design of all proposed drainage structures and will influence the layout of the site plan. The analysis will set the basic parameters for the grading design.
Specifically, NWMI will verify all features of the site that could lead to flooding or other water-induced damage at the site in the drainage analysis. The information will cover the possible hydrologic events, their causes, historic and predicted frequencies, and potential consequences to the RPF. The water table will be located, and the potential for radioactive contamination of ground and surface waters will be considered.
The RPF will be located and designed to withstand credible hydrologic events (e.g., floodplain, ponds/lakes). The final design will evaluate the following:
- Facility design bases are derived sufficiently from predicted hydrologic events that there is reasonable assurance that such events would not preclude safe operation and shutdown of the RPF.
Mr. Michael Balazik Page6 Design bases contain provisions to mitigate or prevent uncontrolled release of radioactive material in the event of a predicted hydrologic occurrence. Potential consequences of such an event will be considered or bounded by accidents analyzed in Chapter 13.0 of the final safety analysis report.
- Design bases consider leakage or loss of radioactive materials to ground and surface water, and releases of airborne radioactive material in surface water.
The primary areas of evaluation during the final RPF design will include the design bases for all SSCs that could be affected by predicted hydrological conditions at the site, including impacts on (1) structures resulting from the force or submergence of flooding, (2) systems resulting from instrumentation and control electrical or mechanical malfunction due to water, and (3) equipment (e.g., fans, motors, and valves) resulting from degradation of the electromechanical function due to water.
NWMI will provide reasonable assurance that SSCs would continue to perform required safety functions under credible water damage conditions. In addition, the design will use the applicable local building codes to help ensure that water damage to SSCs at the RPF site would not cause unsafe RPF operation, would not prevent RPF safe shutdown, and would not cause or allow uncontrolled release of radioactive material.
- 4. Spurious Actuations A question was raised during the August 22, 2017 ACRS meeting as to whether evaluations will include the potential for spurious actuations to occur during a fire event leading to an inability to maintain nuclear material in a safe state. To clarify, the fire hazards analysis will evaluate a fire in each fire area containing SSCs important to safety and ensure that equipment is available for maintaining nuclear material in a safe state following a fire . Further analysis will identify all fire-induced circuit failures that could directly or indirectly (e.g., by causing single or multiple spurious actuations) compromise the safe state.
- 5. Uranium Metal Fire The RPF will receive uranium metal from the U.S. Department of Energy, Y-12 Complex in Oak Ridge, Tennessee, as an input to support target fabrication. All targets are fabricated from the uranium metal receipts during initial operation. Uranium metal receipts are significantly reduced once target inventories have been developed to support reactor operations, and the majority of uranium input to target fabrication can be acquired from recycled uranium.
NWMI's current analysis evaluated the packing and shipping of uranium metal in compliance with the ES-3100 container requirements and planned handling at the RPF in NWMI-2015-SAFETY-007, Quantitative Risk Analysis ofFacility Fires and Explosions Leading to Uncontrolled Release ofFissile Material, High- and Low-Dose Radionuclides. As part of the Operating License Application, NWMI will evaluate nonstandard payloads and configurations and failures of hardware/control at the RPF. NWMI will also evaluate worker safety/exposure impact from potential uranium metal fires . As needed, controls will be elevated to IROFS controls to meet 10 CFR 70.61 , "Performance Requirements," for uranium exposure.
Uranium metal fines formed by particle-to-particle abrasion in a convenience can during shipping represents a configuration identified in NWMI-2015-SAFETY-001 , NWMI Radioisotope Production Facility Preliminary Hazards Analysis, and evaluated in NWMI-2015-SAFETY-007. The evaluation in NWMI-2015-SAFETY-007 is based on an existing analysis in SNF-6192-FP, Uranium Pyrophorocity Phenomena and Prediction, of ignition test observations for uranium hydride powder with a characteristic particle diameter of 1.85 micron(µ). The SNF-6192-FP analysis concluded that a particle bed depth of7 millimeters (mm) was required for ignition at ambient temperature, which was consistent with test observations.
Mr. Michael Balazik Page 7 The uranium metal particle size generated by abrasion during shipping was considered unlikely to generate the small particles characterized by uranium hydride formation.
80 NWMI's current evaluation 70 (Figure 1) indicates that significant particle bed depths u 60 (greater than 7 mm) are e'
.3 50 required to observe ignition at ;
ambient temperature, and for Q.
~ 40 this bed depth to accumulate on a metal shape piece during c: 30
.~
shipping or storage is ]i 20 considered highly unlikely (as concluded in NWMl-2015- 10 SAFETY-007). However, 0 further consideration of the 2 3 5 6 7 8 9 10 RPF handling activities, Fines Bed Depth, mm which are not well defined at this time, is recommended. - - 10 micron Particles - - 50 mi cron Particles - - 100 micron Particles While significant material is Figure 1. Calculated Ignition Temperature for Small Deposits of not expected to be generated Fine Uranium Metal by abrasion during shipping, abraded material is likely to separate from bulk metal shapes during handling in the RPF. This handling is characterized as transfer of a weighed quantity of as-received uranium shapes from a convenience can into a container for insertion in a dissolver. A number of alternatives are available for performing the transfer, ranging from transfer to a weighing container one shape at a time to dumping a partial convenience can on a weighing tray. Procedures will be developed to avoid generation of significant fines bed depth, if observed.
One example that could be hypothesized is based on a transfer approach where one shape at a time is moved to a weighing container. Any fines generated during shipping would likely remain in the bottom of the convenience can. Tilting the can for final fines removal at the conclusion of the transfer would produce a deeper fines bed in the comer of the convenience can.
While the uranium metal hardness argument presented in NWMI-2015-SAFETY -007 appears reasonable for limiting the amount of uranium fines generated during shipping, the need for a procedure for handling fines, if observed, as a defense-in-depth feature will be reevaluated during development of the Operating Licensing Application.
In addition, NWMI plans to implement appropriate controls in the hood/glovebox to extinguish a uranium metal fire (e.g. magnesium oxide sand) per DOE-HDBK-1081-2014, Primer on Spontaneous Heating and Pyrophoricity. Examples of extinguishing a uranium metal fire in a hood/glovebox include :
- Uranium (metal) fires should not be approached without protective clothing and respirators unless the fire is enclosed in a glovebox. The most effective agent for extinguishing uranium fires has been found to be magnesium oxide sand. Gloveboxes that contain pyrophoric forms of uranium should also contain an amount of magnesium oxide adequate for extinguishment. The burning uranium should be completely covered with sand to as great a depth as possible. The magnesium oxide extinguishes the fire by providing a heat sink, which cools the uranium, and by providing a barrier that limits the availability of oxygen.
Mr. Michael Balazik Page 8
- Argon is a very effective extinguishing agent, providing the oxygen content in the atmosphere is maintained at 4 percent or less. Above 4 percent oxygen, flooding with argon will not extinguish a uranium fire. This is an important point, since the ability to reduce the oxygen content to 4 percent or less during argon flooding in most fume hoods is nearly impossible. Argon may be used effectively to cool the burning uranium prior to application of the magnesium oxide sand.
- Typical foam or dry chemical agents are not effective extinguishing agents. Fusible salt agents have been shown to be effective on small-scale fires. However, the expansion that accompanies the oxidation of uranium has caused the fusible salt coating to crack, allowing the uranium to reignite.
- Water is generally acceptable for use as an extinguishing agent for fires involving uranium. In rare cases where criticality safety considerations preclude the introduction of moderators such as water, suitable alternative fire protection measures need to be incorporated into the facility design. Proper housekeeping, which includes removal of combustibles from pyrophoric forms of uranium, is the most important aspect of fire loss minimization.
NWMI is submitting this response to the NRC in accordance with 10 CFR 50.30(b), "Oath or Affirmation," and 10 CFR 50.4, "Written Communications."
I solemnly declare and affirm that the foregoing information is true and correct under the penalty of perjury.
Executed on September 18, 2017.
If you have questions, I can be reached at (509) 430-6921 or carolyn.haass@nwmedicalisotopes.com.
Sincerely, c~e.~
Carolyn C. Haass Chief Operating Officer cc: Mr. Alexander Adams Research and Test Reactors Branch A Office of Nuclear Reactor Regulation