Leakage, worst-case

U.S. EPA also determined the total quantity of liquids entering the two bottom liner systems over a 10-year time span with a constant top liner leak rate of 50 gallons/acre/day. A composite bottom liner with an intact FML accumulates around 70 gal/acre, primarily through water vapor transmission. Even with a 10-ft tear, which would constitute a worst-case leakage scenario, a composite liner system will allow 47,000-50,000 gallons/acre to enter that bottom liner over a 10-year time span. Compacted soil liners meeting the 10-7 cm/s permeability standard will allow significant quantities of liquids into the bottom liner, and potentially out of the unit over time, on the order of hundreds of thousands of gal/acre.5... 

Compliance with U.S. EPA s design performance standards can be demonstrated through one-dimensional, steady-state flow calculations, instead of field tests. For detection sensitivity, the calculation of flow rates should assume uniform top liner leakage. For detection time, factors such as drain spacing, drainage media, bottom slope, and top and bottom liners should all be considered, and the worst-case leakage scenario calculated. 

Perhaps more serious would be the bypassing of small quantities of regenerant solutions. The worst case would be leakage of hardness-laden HCl effluent, which has a much higher concentration than the feed brine itself, into the product brine. 

Since the core configuration Is not known now and could take many forms before head removal occurs ( 2 years), the possibQity exists that an undesirable fuel state could materialize. Considering the worst cases mentitmed above and the reactivity effects of fuel bumup (-2.5% Ak/k) and neutron leakage (-1.6% Ak/k) along with a boron worth of —0.41 X lO" Ap/ppm, maintenance of a 3500-ppm boron concentration is recommended for TMI>2. 

Criticality analysis of the proposed Maine Yankee nt fuel racks was done with two methodologies NITAWL-KENO with the 123-group XSDRN library and LEOPARD-RODWORTH-PDQ (Refs. 6, 7, and 8), with four- up collapsed cross sections. In both methods, a two-dimensional (x-y) model of the rack was constructed froin a basic unit of the rack. The basic unit of the rack is one-quarter of a fuel assembly and rack unit. Cali ulations are done assuming no leakage in either axial or radial direction i.e., reflecting boundary conditions. In addition, the models for Maine Yankee s spent fuel racks employed worst-case" mechanical uncertainties with fresh fuel at 68°F to bound reactivity eHects. 

APIOOO structures provide adequate segregation of safety-significant SSCs in the event of the worst case steam leakage, this includes the transient differential pressure. 

The worst case steam leakage does not prevent safety-significant SSCs from achieving their safety functions. This includes spray shields and environmental qualification of electrical equipment and containment valves. 

As an aid in determining the severity of vapor cloud explosions, overpressure radius circles are normally plotted on a plot plan from the source of leakage or ignition. Computer applications are available that can easily calculate and plot these on electronic plant design and drafting applications. These overpressure circles can be determined at the levels at which destructive damage may occur to the facility from the worst case credible event (WCCE). 

One of the most undesirable problems in batteries for domestic use has been the leakage of electrolyte solutions. The sources of this trouble are mainly abuses like the reverse connection between more than one cell, and caushc alkaline or strong acidic electrolyte solutions could cause chemical burns or worse. In the case of LIB5, they contain flammable constituents including organic electrolyte solutions and lithiated carbon, and the electrolyte leakage might lead to an accidental fire in the worst possible case. 

---