Have you noticed, looking at the famous ASME B31.1 support spacing Table 121.5, that the spacing between pipe supports is roughly “size + 10”, in other words, the spacing between supports on an 1 inch instrument tubing would be “1 + 10” = 11 ft, while the spacing on a 6 inch line for example […]
FAILURE MODE – When an explosion (either a subsonic deflagration, or a supersonic detonation) occurs in a metallic vessel, one of three things can happen: Case 1 – Containment: The vessel can contain the explosion, elastically as if nothing happened, or with plastic bulging. Case 2 – Rupture: The vessel can rupture, without ejecting fragments. […]
Nonmetallic composite wrap repairs are wraps comprising two constituents: A fabric woven from a fiber such as graphite or glass A thermoset polymer such as a two-component mix epoxy resin. This material is also referred to as fiber-reinforced polymer (FRP). These repairs can be liners wrapped inside, or jackets wrapped over a corroded pipe. There […]
A lesson from the Fukushima Dai-Ichi accident – The series of events that followed the March 11, 2011 tsunami caused hydrogen explosions that damaged the reactor buildings of three units at Fukushima Dai-ichi. In June 2013, the US NRC issued order EA-13-109 “Order to Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of […]
Following the 2011 tsunami and accident at Fukushima-Daiichi in Japan, the nuclear power industry has embarked on a significant effort to evaluate the effect of beyond-design-basis (BDB) events, particularly earthquakes, tsunamis, and floods, on the safety of nuclear power plants. What are BDBs? Beyond-design-basis (BDB) events (sometimes also labeled BDBE) are accident sequences that have […]
When planning or performing a wall thickness inspection of buried pipe, it is necessary to establish the procedure to be used in evaluating the thickness readings, and determine the pipe’s fitness-for-service (FFS), which will be the basis of run-or-repair decisions. We are currently working with EPRI to develop such a procedure. This article is intended […]
Buried steel pipe is prone to pitting due to external (soil-side) corrosion and internal (water-side) corrosion and biofouling. Preventive and mitigative measures include periodic inspection, cleaning, chemical and biocide treatments, and repairs. A cost-effective alternative consists in replacing the buried steel pipe with a non-metallic pipe, in particular high density polyethylene (HDPE). This alternative, widely […]
Nuclear power plants are designed, constructed, operated and inspected to prevent pipe ruptures. Despite these preventive measures, plants are designed to mitigate the effects of hypothetical pipe ruptures. The hypothetical ruptures are in the form of leakage cracks and, for high energy lines (operating temperatures in excess of 200 degrees F or operating pressures in […]
