Safety Goal

The functional concept shall consist of clearly use-cases and shall be unique and as atomic as possible, so that no functional dependencies are already part of the ITEM Definition. If so Hazard Analysis and Risk Assessment becomes very complex and the result are overlapping within the safety goals. 

Malfunctions can occur in different environments, various driving situations and different performance or the impulse characteristic can have a varying influence on the driver, which can lead to more or less severe dangers. The parameters or assumptions used to define the safety goal have to be clearly specified. 

Safety Goals are defined on the vehicle level (ITEM) according to ISO 26262. In this context there is no guideline to how complex or at which horizontal abstraction level is described. A safety goal can be formulated as follows Avoid an inadmissible pressure build-up of the brake pressure on one wheel , Avoid an inadmissible torque build-up on one wheel or Avoid a defective blockade of one wheel . Basically, aU three formulations could be correct. However, if we use such differing description levels for a vehicle system or multiple vehicle systems that have to be integrated into a vehicle, it could start to become confusing, since the interfaces will not match one another (compare also to Fig. 4.9). 

Safety goals often describe mutual effects of possible malfunctions. A defective, far too high motor torque leads at a certain value, intensity or duration to a dangerous and for the driver, uncontrollable self-acceleration of the vehicle. A defective far too low motor torque could lead to an uncontrollable delay up until self-braking. This is why the safest function is usually a corridor, which is chosen by design limitations and/or the controllability through the driver (see Fig. 4.15). 

If we consider the function reduce vehicle speed , unintentionally or uncontrollable behavior for the driver due to malfunctions could happen. In order to ftilly comprehend the safety goal it is important to know how much and when which torques characteristics are considered to be correct. Furthermore, it has to he clear that after the requirement for braking, the function must have faded within a certain period of time otherwise residual torques could again lead further endangerments. This means that the space of the correct function needs to be specified precisely otherwise the dangerous range could not even be determined. 

---

The NRC safety goal can be evaluated by comparison to the risks from accidents incurred from other human activities (Eig. 2) (29). The safety goal and the safety record of the nuclear power industry indicate much lower societal risks from commercial nuclear power than from a wide range of other common human activities. 

However, even when we determine that the benefits of an inherently less safe technology justify its use, we should always continue to look for inherently safer alternatives. Technology continues to evolve and advance, and inherently safer alternatives which are not economically attractive today may be very attractive in the future. The development of new inherently safer technology offers the promise of more reliably and economically meeting process safety goals. 

Chemical reactions are sometimes conducted in a dilute solution to moderate reaction rates, to provide a heat sink for an exothermic reaction, or to limit maximum reaction temperature by tempering the reaction. In this example there are conflicting inherent safety goals—the solvent moderates the chemical reaction, but the dilute system will be significantly larger for a given production volume. Careful evaluation of all of the process risks is required to select the best overall system. 

Discus.sions continued and in August 1986 the formal statement was issued by the NRC (I x. dcruI Rcgister 51 162 p30029 - 30033). The two qualitative. safety goals are ... 

The. statement goes on to acknowledge the contribution of the Reactor Safety Study (WASH-1400) to risk quantification but points out that safety goals were not the study objectives and that the uncertainties make it unsuitable for such a purpose. After pointing out that the death I f any individual is not "acceptable," it states two quantitative objectives ... 

These are addressed ind The Backfit Rule (10 CFR 50.109, and the NRC Safety Goal Policy Statement (SECY-89-102). The Backfit Rule applies not to the regulated industry, but to the NRC staff. It says that backfitting is required if it will result in substantial increase in safely and the direct and indirect costs of backfitting are justified. (This limitation does not apply if the modification is necessary for compliance with regulations). 

The Safety Goal Policy Statement was published to define acceptable radiological risk IVom nuclear power plant operation, and by implication provide a de minimus risk to be assured without cost considerations. Safety beyond the minimum requires cost-benefit analysis. Since being promulgated, bulletins and generic letters have been imposed to enhance safety, under the provisions of 10 CFR 50.109, the Backfit Rule. 

Individual plants, with extra safety features, may exceed the Safety Goals. The fue plants analyzed in NUREG-1150 meet or exceed the Safety Goals. This approach is contained in the Regulatory Analysis Guidelines (NUREG/CR-0058). 

Risk-based information provides a foundation for regulation of severe accidents. Early PRAs, with large uncertainties, indicated risk that was above or below the Safety Goals depending on containment performance. Consequently the NRC developed an Integration Plan for Closure of Severe Accident Issues (SECY-88-47) with six main elements to this plan 1) individual plant examinations (IPE), 2) containment performance improvements, 3) improved plant oper itions, 4) severe accident research, 5) external event considerations, and 6) accident management. 

An Approach to Quantitative Safety Goals for Nuclear Power Plants, October 1980. Rasedag, W. F. et al., Regulatory Impact on Nuclear Reactor Accident Source Term Assumptions, June 1981. 

Blond, R., The Development Severe Reactor Source Terms 1957-1981, November 1982. Safety Goals for Nuclear Power Plant Operation May 1983. 

Mattson et al., 1980, Concepts, Problems and Issues in Developing Safety Goals and Objectives for Commercial Nuclear Power, Nuclear Safety 21, pp 703-716, November-December. 

SECY-89-102,1990, Implementation of the Safety Goals, USNRC, memorandum from S. J. Chalk to J. M. Taylor. 

The worker knew that valve A had to be closed. However, it was believed by the workforce that despite the operating instructions, closing B had a similar effect to closing A and in fact produced less disruption to downstream production. Possible cause violation as a result of mistaken information and an informal company culture to concentrate on production rather than safety goals (wrong intention). 

NRC safety goal, 17 540-541. See also U.S. Nuclear Regulatory Commission (NRC)... 

NRC), 17 528, 532, 539, 597-598. See also NRC safety goal radioactive waste treatment under,... 

The Joint Commission Website http //www.jointcommission.org. National Patient Safety Goals document. 

Good engineering practices should target pressure drop less than 500 kPa/km (2 psi/100 ft). For the small injection scheme, pressure drop is usually not a significant factor. For larger acid gas systems it may be necessary to exceed this amount in order to achieve safety goals (i.e., less fluid contained, and potentially released, in the pipeline). 

The JCAHO annually publishes six national patient safety goals and surveys the accredited organizations related to them. The initial six goals include several medication-related safety improvements ... 

Joint commission announces national patient safety goals, July 24,2002. Available at www.jcaho.org, accessed August 5, 2002. 

Sentinel event reporting and patient safety goals.385... 

Chapter 4—Choosing Appropriate Metrics based on identified process safety goals and objectives... 

---