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At least 523 records · Page 29

Markov Model of Accident Progression at Fukushima Daiichi

On March 11, 2011, a magnitude 9.0 earthquake followed by a tsunami caused loss of offsite power and disabled the emergency diesel generators, leading to a prolonged station blackout at the Fukushima Daiichi site. After successful reactor trip for all operating reactors, the inability to remove decay heat over an extended period led to boil-off of the water inventory and fuel uncovery in Units 1-3. A significant amount of metal-water reaction occurred, as evidenced by the quantities of hydrogen generated that led to hydrogen explosions in the auxiliary buildings of the Units 1 & 3, and in the de-fuelled Unit 4. Although it was assumed that extensive fuel damage, including fuel melting, slumping, and relocation was likely to have occurred in the core of the affected reactors, the status of the fuel, vessel, and drywell was uncertain. To understand the possible evolution of the accident conditions at Fukushima Daiichi, a Markov model of the likely state of one of the reactors was constructed and executed under different assumptions regarding system performance and reliability. The Markov approach was selected for several reasons: It is a probabilistic model that provides flexibility in scenario construction and incorporates time dependence of different model states. It also readily allows for sensitivity and uncertainty analyses of different failure and repair rates of cooling systems. While the analysis was motivated by a need to gain insight on the course of events for the damaged units at Fukushima Daiichi, the work reported here provides a more general analytical basis for studying and evaluating severe accident evolution over extended periods of time. This work was performed at the request of the U.S. Department of Energy to explore 'what-if' scenarios in the immediate aftermath of the accidents.

08 HYDROGEN↗

Thermally switchable dielectrics

Precursor polymers to conjugated polymers, such as poly(phenylene vinylene), poly(poly(thiophene vinylene), poly(aniline vinylene), and poly(pyrrole vinylene), can be used as thermally switchable capacitor dielectrics that fail at a specific temperature due to the non-conjugated precursor polymer irreversibly switching from an insulator to the conjugated polymer, which serves as a bleed resistor. The precursor polymer is a good dielectric until it reaches a specific temperature determined by the stability of the leaving groups. Conjugation of the polymer backbone at high temperature effectively disables the capacitor, providing a `built-in` safety mechanism for electronic devices.

36 MATERIALS SCIENCE↗

System and method for modeling and analyzing complex scenarios

An embodiment of the present invention includes a method for analyzing and solving possibility tree. A possibility tree having a plurality of programmable nodes is constructed and solved with a solver module executed by a processor element. The solver module executes the programming of said nodes, and tracks the state of at least a variable through a branch. When a variable of said branch is out of tolerance with a parameter, the solver disables remaining nodes of the branch and marks the branch as an invalid solution. The valid solutions are then aggregated and displayed as valid tree solutions.

97 MATHEMATICS AND COMPUTING↗

System and method for disrupting suspect objects

A system and method for disrupting at least one component of a suspect object is provided. The system includes a source for passing radiation through the suspect object, a screen for receiving the radiation passing through the suspect object and generating at least one image therefrom, a weapon having a discharge deployable therefrom, and a targeting unit. The targeting unit displays the image(s) of the suspect object and aims the weapon at a disruption point on the displayed image such that the weapon may be positioned to deploy the discharge at the disruption point whereby the suspect object is disabled.

42 ENGINEERING↗

Method and apparatus for low power analog-to-digital conversion

A method and apparatus for analog-to-digital conversion. An Analog-to-Digital Converter (ADC) includes M ADC.sub.j, j=1, 2, . . . , M. Each ADC.sub.j comprises a number of cells each of which comprises a first switch, a second switch, a current sink and an inverter. An inverter of a cell in an ADC.sub.j changes state in response to a current associate with an input signal of the ADC.sub.j exceeding a threshold, thus switching on the next cell. Each ADC.sub.j is enabled to perform analog-to-digital conversion on a residual current of a previous ADC.sub.j-1 after the previous ADC.sub.j-1 has completed its analog-to-digital conversion and has been disabled.

42 ENGINEERING↗

Grid-based precision aim system and method for disrupting suspect objects

A system and method for disrupting at least one component of a suspect object is provided. The system has a source for passing radiation through the suspect object, a grid board positionable adjacent the suspect object (the grid board having a plurality of grid areas, the radiation from the source passing through the grid board), a screen for receiving the radiation passing through the suspect object and generating at least one image, a weapon for deploying a discharge, and a targeting unit for displaying the image of the suspect object and aiming the weapon according to a disruption point on the displayed image and deploying the discharge into the suspect object to disable the suspect object.

42 ENGINEERING↗

Los Alamos, Toshiba probing Fukushima with cosmic rays

Los Alamos National Laboratory has announced an impending partnership with Toshiba Corporation to use a Los Alamos technique called muon tomography to safely peer inside the cores of the Fukushima Daiichi reactors and create high-resolution images of the damaged nuclear material inside without ever breaching the cores themselves. The initiative could reduce the time required to clean up the disabled complex by at least a decade and greatly reduce radiation exposure to personnel working at the plant. Muon radiography (also called cosmic-ray radiography) uses secondary particles generated when cosmic rays collide with upper regions of Earth's atmosphere to create images of the objects that the particles, called muons, penetrate. The process is analogous to an X-ray image, except muons are produced naturally and do not damage the materials they contact. Muon radiography has been used before in imaginative applications such as mapping the interior of the Great Pyramid at Giza, but Los Alamos's muon tomography technique represents a vast improvement over earlier technology.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Reimagining Building Sensing and Control (Presentation)

Buildings are responsible for 40% of US energy consumption, and sensing and control technologies are an important element in creating a truly sustainable built environment. Motion-based occupancy sensors are often part of these control systems, but are usually altered or disabled in response to occupants' complaints, at the expense of energy savings. Can we leverage commodity hardware developed for other sectors and embedded software to produce more capable sensors for robust building controls? The National Renewable Energy Laboratory's (NREL) 'Image Processing Occupancy Sensor (IPOS)' is one example of leveraging embedded systems to create smarter, more reliable, multi-function sensors that open the door to new control strategies for building heating, cooling, ventilation, and lighting control. In this keynote, we will discuss how cost-effective embedded systems are changing the state-of-the-art of building sensing and control.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Implications of an Improvised Nuclear Device Detonation on Command and Control for Surrounding Regions at the Local, State and Federal Levels

This paper discusses command and control issues relating to the operation of Incident Command Posts (ICPs) and Emergency Operations Centers (EOCs) in the surrounding area jurisdictions following the detonation of an Improvised Nuclear Device (IND). Although many aspects of command and control will be similar to what is considered to be normal operations using the Incident Command System (ICS) and the National Incident Management System (NIMS), the IND response will require many new procedures and associations in order to design and implement a successful response. The scope of this white paper is to address the following questions: • Would the current command and control framework change in the face of an IND incident? • What would the management of operations look like as the event unfolded? • How do neighboring and/or affected jurisdictions coordinate with the state? • If the target area’s command and control infrastructure is destroyed or disabled, how could neighboring jurisdictions assist with command and control of the targeted jurisdiction? • How would public health and medical services fit into the command and control structure? • How can pre-planning and common policies improve coordination and response effectiveness? • Where can public health officials get federal guidance on radiation, contamination and other health and safety issues for IND response planning and operations?

command and control, Incident Command Post, ICP, E↗

System and method for controlling hydraulic pressure in electro-hydraulic valve actuation systems

A control system for an engine includes a first lift control module and a second lift control module. The first lift control module increases lift of M valves of the engine to a predetermined valve lift during a period before disabling or re-enabling N valves of the engine. The second lift control module decreases the lift of the M valves to a desired valve lift during a period after enabling or re-enabling the N valves of the engine, wherein N and M are integers greater than or equal to one.

33 ADVANCED PROPULSION SYSTEMS↗

Increasing security in inter-chip communication

An apparatus for increasing security in inter-chip communication includes a sending control module, a communication bus, and a receiving control module. The communication bus is coupled between the sending control module and the receiving control module. The sending control module operates to send data on the communication bus, disable the communication bus when threats are detected, or both.

97 MATHEMATICS AND COMPUTING↗

Method for programming a flash memory

A method of programming a flash memory is described. The method includes partitioning a flash memory into a first group having a first level of write-protection, a second group having a second level of write-protection, and a third group having a third level of write-protection. The write-protection of the second and third groups is disabled using an installation adapter. The third group is programmed using a Software Installation Device.

97 MATHEMATICS AND COMPUTING↗

Supercomputer Simulations Help Develop New Approach to Fight Antibiotic Resistance

ORNL leveraged powerful supercomputing to support research led by University of Oklahoma scientists to identify chemicals that seek out and disrupt bacterial proteins called efflux pumps, known to be a major cause of antibiotic resistance. By running simulations on Titan, the team selected molecules most likely to target and potentially disable the assembly of efflux pumps found in E. coli bacteria cells.

47 OTHER INSTRUMENTATION↗

Exploring Operational Safeguards, Safety, and Security by Design to Address Real Time Threats in Nuclear Facilities

Over the last few years, significant attention has been paid to both encourage application and provide domestic and international guidance for designing in safeguards and security in new facilities.1,2,3 However, once a facility is operational, safeguards, security, and safety often operate as separate entities that support facility operations. This separation is potentially a serious weakness should insider or outsider threats become a reality.Situations may arise where safeguards detects a possible loss of material in a facility. Will they notify security so they can, for example, check perimeter doors for tampering? Not doing so might give the advantage to an insider who has already, or is about to, move nuclear material outside the facility building. If outsiders break into a facility, the availability of any information to coordinate the facility’s response through segregated alarm stations or a failure to include all available radiation sensors, such as safety’s criticality monitors can give the advantage to the adversary who might know to disable camera systems, but would most likely be unaware of other highly relevant sensors in a nuclear facility.This paper will briefly explore operational safeguards, safety, and security by design (3S) at a high level for domestic and State facilities, identify possible weaknesses, and propose future administrative and technical methods, to strengthen the facility system’s response to threats.

Schanfein, Mark J.↗

Architecture and Methods for Substation SCADA Cybersecurity: Best Practices

There are over 3000 electricity providers in the United States, encompassing investor and publicly owned utilities as well as electric cooperatives. There has been ongoing trends to increasingly automate and provide remote control and monitoring of electric energy delivery systems. The deployment of computer network technologies has increased the efficiency and reliability of electric power infrastructure. However, the increased use of digital communications has also increased the vulnerability to malicious cyber attacks [1]. In 2004 the National Research Councils (National Academies) formed a committee of specialists to address these vulnerabilities and propose possible solutions with an objective to prioritize the R&D needs for developing countermeasures. The committee addressed many potential concerns in the electric power delivery system and classified them based upon different criteria and presented recommendations to minimize the gap between the academic research directions and the needs of the electric utility industry. The complexity and diversity of the electric power delivery system in the U.S. has opened many ports for attackers and intruders [1]. This complexity and diversity is attributed to the fact that power delivery system is a network of substations, transmission and distribution lines, sub-networks of controlling, sensing and monitoring units, and human operator involvement for running the system [1]. Accordingly, any incident such as the occurrence of a fault or disturbance in this complex network cannot be deferred and should be resolved within an order of milliseconds, otherwise there is risk of large-scale outages similar to the occurrences in India and the U.S. in 2003 [2]. There are three main vulnerabilities in supervisory control and data acquisition (SCADA) systems commonly identified—physical vulnerability, cyber vulnerability and personal vulnerability [1]. In terms of cyber threats, SCADA systems are the most critical elements in the electric power grid in the U.S. Unauthorized access to a SCADA system could enable/disable unexpected equipment (such as disable the protection system or a circuit breaker) which could cause large scale disruptions of electric power delivery. This paper provides an overview of power system SCADA technologies in transmission substations (Section 2) and summarizes the best practices for implementing a cyber security program. After introducing SCADA system operations in Section 2, a description of the security challenges for SCADA systems is presented in Section 3. In Section 4, NECRC Critical Infrastructure Protection standards CIP-002 through CIP-009 are summarized. An overview of industry best practices is presented in Section 5.

97 MATHEMATICS AND COMPUTING↗

A STRONGLY COUPLED REACTOR CORE ISOLATION COOLING SYSTEM MODEL FOR EXTENDED STATION BLACK-OUT ANALYSES

The reactor core isolation cooling (RCIC) system in a boiling water reactor (BWR) provides makeup cooling water to the reactor pressure vessel (RPV) when the main steam lines are isolated and the normal supply of water to the reactor vessel is lost. The RCIC system operates independently of AC power, service air, or external cooling water systems. The only required external energy source is from the battery to maintain the logic circuits to control the opening and/or closure of valves in the RCIC systems in order to control the RPV water level by shutting down the RCIC pump to avoid overfilling the RPV and flooding the steam line to the RCIC turbine. It is generally considered in almost all the existing station black-out accidents (SBO) analyses that loss of the DC power would result in overfilling the steam line and allowing liquid water to flow into the RCIC turbine, where it is assumed that the turbine would then be disabled. This behavior, however, was not observed in the Fukushima Daiichi accidents, where the Unit 2 RCIC functioned without DC power for nearly three days. Therefore, more detailed mechanistic models for RCIC system components are needed to understand the extended SBO for BWRs. As part of the effort to develop the next generation reactor system safety analysis code RELAP-7, we have developed a strongly coupled RCIC system model, which consists of a turbine model, a pump model, a check valve model, a wet well model, and their coupling models. Unlike the traditional SBO simulations where mass flow rates are typically given in the input file through time dependent functions, the real mass flow rates through the turbine and the pump loops in our model are dynamically calculated according to conservation laws and turbine/pump operation curves. A simplified SBO demonstration RELAP-7 model with this RCIC model has been successfully developed. The demonstration model includes the major components for the primary system of a BWR, as well as the safety system components such as the safety relief valve (SRV), the RCIC system, the wet well, and the dry well. The results show reasonable system behaviors while exhibiting rich dynamics such as variable flow rates through RCIC turbine and pump during the SBO transient. The model has the potential to resolve the Fukushima RCIC mystery after adding the off-design two-phase turbine operation model and other additional improvements.

RCIC↗

Impacts of Vehicle (In)Security

Nuclear and radioactive material is routinely transported worldwide every day. Since 2010, the complexity of the transport vehicle to support such activities has grown exponentially. Many core functions of a vehicle are now handled by small embedded computer modules with more being added each year to enhance the owner’s experience and convenience. With a system as complex as today’s automobile, the potential for cyber security issues is certain. Hackers have begun exploring this new domain with public information increasingly disseminated. Because vehicles are allowed into and around secure nuclear facilities, the potential for using a vehicle as a new cyber entry point or vector into the facility is now plausible and must be mitigated. In addition, compromising such a vehicle could aide in illicit removal of nuclear material, putting sensitive cargo at risk. Because cyber attacks can now be introduced using vehicles, cyber security, needs to be integrated into an organization’s design basis threat document. Essentially, a vehicle now extends the perimeter for which security professionals are responsible.Electronic Control Units (ECU) responsible for handling all core and ancillary vehicle functions are interconnected using the controller area network (CAN) bus. A typical CAN network in a modern automobile contains 50 or more ECUs. The CAN protocol now supports a wide variety of areas, including automotive, road transportation, rail transportation, industrial automation, power generation, maritime, military vehicles, aviation, and medical devices. In many ways, the nuclear industry is employing the CAN bus protocol or other similar broadcast serial networks. This paper will provide an overview of the current state of automobile and CAN Bus security, as well as an overview of what has been publicly disclosed by many research organizations. It will then present several hypotheses of how vehicle security issues may impact nuclear activities. An initial discussion of how a vehicle can be used as a new threat vector to penetrate secure facilities will be presented. This includes how a modern automobile can be used as the exploitation mechanism for nearby devices such as laptops, cell phones, and wireless access points. Additional discussion will highlight how vehicle security might impact transportation of nuclear material through remote exploitation of a moving vehicle. The final discussion will include what possible implications might be relative to the physical protection systems at nuclear facilities. The audience will also be given details regarding the complexity of attack, thus implying the likelihood of successful exploitation, and information on how such attacks may be mitigated. Emerging security products for automobiles will be discussed and other mitigation methods will be detailed (e.g. disabling vehicle cellular modems). As a result, the audience will have a greater understanding of how to add vehicle security as a part of a comprehensive nuclear security policy.Finally, this paper will highlight the similarities between CAN Bus and other broadcast serial bus networks such as Profibus or DeviceNet, helping educate the reader on how susceptible this type of networking is to nefarious attacks and how it might affect components connected to many different nuclear systems, including control systems, safety systems, emergency systems, and support systems.

47 OTHER INSTRUMENTATION↗

Increasing security in inter-chip communication

An apparatus for increasing security in inter-chip communication includes a sending control module, a communication bus, and a receiving control module. The communication bus is coupled between the sending control module and the receiving control module. The sending control module operates to send data on the communication bus, disable the communication bus when threats are detected, or both.

99 GENERAL AND MISCELLANEOUS↗