Safety feature

This section shall briefly state the basic safety principles adopted for the 

Primary coolant parameters - sodium temperature at core inlet, °C 382 377 

Tertiary system parameters - superheated steam temperature,°C 495 505 

Notes with vessel-type SG, with sectional-modular SG. 

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An important safety feature on every modern rig is the blowout preventer (BOP). As discussed earlier on, one of the purposes of the drilling mud is to provide a hydrostatic head of fluid to counterbalance the pore pressure of fluids in permeable formations. However, for a variety of reasons (see section 3.6 Drilling Problems ) the well may kick , i.e. formation fluids may enter the wellbore, upsetting the balance of the system, pushing mud out of the hole, and exposing the upper part of the hole and equipment to the higher pressures of the deep subsurface. If left uncontrolled, this can lead to a blowout, a situation where formation fluids flow to the surface in an uncontrolled manner. 

Most cleaners are available for < 2.20/kg either as a dry blend or as aHquid. Liquid cleaners are usually less expensive than the dry blend type. A trend toward Hquid cleaners is evident as of this writing (ca 1994) because of convenience features such as automatic additions of the cleaner by chemical feed pump. Safety features such as minimized heat generation upon blending with water to make the desired concentration are also important. 

Many redundant safety features were provided at the SRP. These included a moderator dump tank, gadolinium nitrate solution as emergency absorber, continuously mnning diesel generators, and a 95 x 10 -L (25 x 10 -gal) elevated water tank for each reactor, for assurance of cooling. 

Fig. 13. Proposed advanced PWR design having passive safety features (79). Courtesy of Westiaghouse Electric Corp.

The development of computer capabiUties in hardware and software, related instmmentation and control, and telecommunication technology represent an opportunity for improvement in safety (see COMPUTER TECHNOLOGY). Plant operators can be provided with a variety of user-friendly diagnostic aids to assist in plant operations and incipient failure detection. Communications can be more rapid and dependable. The safety control systems can be made even more rehable and maintenance-free. Moreover, passive safety features to provide emergency cooling for both the reactor system and the containment building are being developed. 

The API Standard gives considerable information on the construction and safety features of such installations. It also recommends minimum distances from property hnes. The user may wish to obtain added safety by increasing these distances. 

Safety features such as overspeed trip, low-od trip, remote-solenoid trip, vibration monitor, or other special monitoring of temperature, temperature changes, and casing and rotor expansion... 

They have in-built safety features to prevent excessive frequent starting, by means of thermostats and low-level electrolyte monitors... 

A process industry, a refinery, a petrochemical, a fertilizer plant or a povser station are installations that can be classilled as critical. They cannot afford a breakdown during normal operation and would prefer to incorporate more safety features into the drive motors, even if these are expensive. These features can be one or more of the following. 

Provisions must be made for safety features such as padlocking and door interlocking arrangements. Door... 

The above are the more obvious constructional, design and safety features for a switchgear or a controlgear assembly. For more details and additional requirements refer to lEC 60439-1 for LT, lEC 60298 and lEC 60694 for FIT and ANSI-C-37/20C, common for LT and FIT switchgear and controlgear assemblies. 

Dependent upon the chemicals in-process, each of these may introduce a range of hazards, e.g. chemical, flammable or mechanical. These must be checked in every case. Safety features which may be required are summarized in Table 7.21. 

Table 7.21 Safety features in chemical engineering operations...

Never use free aeetylene at pressures above 9 psig (0.62 bar) unless speeial safety features are employed. 

Consideration should be given to the safety features listed in Table 7.21. 

Article containing a primary explosive substance and not containing two or more independent safety features B... 

Secondary detonating explosive substance or black powder or article containing a secondary detonating explosive substance, in each case without means of initiation and without a propelling charge, or article containing a primary explosive substance and containing two or more independent safety features D... 

The pictures in Fig. 21 demonstrate retroreflective film applications on a truck. The retroreflective part of the graphic in the daylight picture is still visible at night when the headlights of an approaching vehicle hit the surface. This makes it also an important safety feature by improving nighttime visibility. 

An applicant for a construction permit files a Preliminary Safety Analysis Repori (PSAR) presenting design criteria and preliminary design information, hypothetical accident analyses, safety features, and site data. An Environmental Report (ER) must be submitted to evtiluatc the env ironmental impact of the proposed facility, and information must be submitted to the. Uornev Cieneral and the NRC staff for antitrust review. 

Discuss why the EPZ should be independent of plant size, safety features, demography and meteorology. 

Function event trees include primarily the engineered safety features of the plant, but other systems provide necessary support functions. For example, electric power system failure amid reduce the effectiveness of the RCS heat-removal function after a transient or small UJ( A. Therefore, EP should be included among the systems that perform this safety function. Siipfiort systems such as component-cooling water and electric power do not perform safety functions directly. However, they significantly contribute to the unavailability of a system or group of systems that perform safety functions. It is necessary, therefore, to identify support systems for each frontline ssstcm and include them in the system analysis. 

The preceding overviewed the operation and engineered safety features of current and advanced LWRs. Before preceding to describe how PSA is performed on nuclear power plants, two accidents are described that have profoundly affected the industiy... 

Ceitain engineered safety features (containment sprays, suppression pools, ice condenscr.s i will effectively remove fission products regardless of form. Other ESF such as filters are less effective. 

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). 

Answer The only reason I can think of for making the EPZ independent of plant size, safety features, demography and meteorology is the convenience of emergency planners. Such would take no consideration for the hazard a plant poses it would favor hazardous activity and penalize safe activity. 

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