Credit risk control

Greater control by settlement banks over the credit risks run on their customers (by means of a debit-capped payment mechanism). 

Measuring and Controlling Interest Rate and Credit Risk Second Edition by Frank J. Fabozzi, Steven V. Mann, and Moorad Choudhry Professional Perspectives on Fixed Income Portfolio Management, Volume 4 edited by Frank J. Fabozzi... 

Pierides, Y. 1997. The Pricing of Credit Risk Derivatives. Journal of Economic Dynamics and Control 5, 1579—1611. 

When a fire occurs, it is assumed that all fluid flow to and from the fire risk area has been stopped. Therefore, flow loads such as control valve failure or incoming feed streams are not additive to the fire load. Credit is not generally given to flow out through normal channels, since they could also be blocked during the fire emergency. 

Obviously, an important component of risk communication is if you do not know an answer or are uncertain, acknowledge it and do not hesitate to admit mistakes or disclose risk information. The Centers for Disease Control, to their credit, did admit they made mistakes about the information they supplied initially about anthrax, during the anthrax exposures to postal workers during October 2001. They stated that only workers who opened the letters contaminated with anthrax were at risk. It turned out that the spores could migrate out of the unopened letters, which ended up exposing other postal workers. 

Step 1 - Complete the LOPA without taking any credit for the SIF. First, determine the initiating events from HAZOP/What-if/EMEA study. Next, evaluate frequencies of all initiating events from company database and industry experience. Then, determine the probability that each IPL will function successfully from an industrial database. PFO yg of some typical protection layers are (CCPS, 2000) BPCS control loop = 0.10 Operator s response to alarm = 0.10 Rehef safety valve = 0.01 to 0.001 and vessel failure probability at maximum design pressure = 10 ". Finally, compare the calculated risk with the tolerable risk target... 

The ICI-MOND Fire Explosion and Toxicity Index (ICI 1985) was derived from DOW one and it is yet appreciated in process industry in many countries, including Italy. In ICI-MOND index method there are some ninety elementary questions, nested in a three levels tree. For many issues there is also a forth level of nested questions. About two thirds of the questions are for penalties and one third for credits accounting. For the most of the questions a quantitative answer is required. The questions are organized in chapters for penalties section the subjects are related to materials and quantities, processes and equipment, layout, health for credits section instead the method deals with containment, control, safety culture, fire engineering and emergency preparedness. Every issue weighs differently in overall risk levels accounting. Results are presented in a structured way, discriminat-iug fire, toxic, confined and unconfined explosion. 

The analysis conducted to determine the hazard categorization is performed without credit taken for engineered features or administrative controls. Examples of engineered features and administrative controls are those specific facility features (not including site location) such as building containment, stacks, equipmoit, systems, actions, or operating conditions, that are established to control risk. For chemical hazards, credit b to be taken for the existing location... 

NOTE 2 Where a detailed hazard analysis of the BPCS demonstrates that the control and protective elemertts within the BPCS are functionally independent, it may be possible to conclude that a failure in the controlling part has a sufficiently low probability of causing the failure of the protective function. In such cases, it may be appropriate to take credit for the BPCS as a protection layer, even if the BPCS can initiate the process hazard. In accordance with ANSI/ISA-84.00.01-2004-1, Clause 9, the risk reduction claimed for the BPCS as a protection layer must be less than or equal to 10. 

As per lEC 61511-3 2003 Clause 9.4.3, operator action as part of safety instrument functions (SIFs) can be credited with a level of risk reduction greater than 10 when the system from the sensor to the final element can be designed and evaluated as an SIS per the requirements of lEC 61511. A typical automated SIS, popularly known as an industrial automation and control system (LACS), from the sensor to the final element can be conceived, as shown in Fig. VIII/1.4-1 or Fig. VII/1.3-1 where the main constituents are sensor, logic solver, and final element. When an operator action such as through the display/alarm is necessary this needs to be as shown in Fig. XI/2.4.3-1. 

In a simple LOPA using a conservative approach, unless there is complete independence in how basic process control functions are implemented through the BPCS, no credit can be taken for any risk reduction provided by a control or alarm function implemented through the BPCS as a protection layer if a BPCS failure also forms part of an initiating event. However, this conservative approach may be relaxed if it can be demonstrated that there is sufficient independence to allow credit to be taken for both. This issue is discussed in Sections 9.4 and 9.5 of BS EN 61511-1 and BS EN 61511 -2. The reader is referred to these sources for a more detailed discussion. Systematic factors such as security, software, design errors and human factors should also be considered. 

The results of the PRA show that the AP1000 has significantly less dependence on operator action to reduce plant risk to acceptable levels than current plants. This was shown through the sensitivity analyses and the operator action contributions from both the risk decrease and risk increase measures. Almost all operator actions credited in this PRA are performed in the control room there are very few local actions outside the control room. Further, the human actions modelled in the AP 1000 PRA are generally simple. Thus, the tasks for AP 1000 operators are easier and less likely to fail. If it were assumed that the operators never perform any actions credited in the PRA, the plant events CDF would still be lower than the result obtained for many eurrent pressurised water reactors including operator actions.This low dependence on operator aetion is therefore ALARP. 

Ci Valuararil Ct.SS Ijoae Control Credit Factor = C, C kCi I =j 0,51 PROCESS UNIT RISK ANALYSIS SUMMAF ... 

The EUC risk (lEC terminology) is then due to a range of mechanical defects and PLC control/instrument defects. The fault tree shows how these defects are grouped imder certain types of hazards all leading up to the potential for an explosion. The failure rates are estimated values but they do comply with the lEC requirement that normal control systems should not be credited with a failure rate lower than 10 per hr. 

---