AEC Research and Development Report

Summary: An EVESR MKI prototype fuel bundle was fully instrumented and operated intermittently for a 5-month period at the Pacific Gas and Electric Company’s Moss Landing Power Station. The vessel was operated up to 1000 psi with steam flows from 3000 to 26,600 lb/h, and steam inlet temperatures up to 825 degrees F. Data was recorded for blowout, vibration, flow distribution, heat transfer and pressure drop. The mechanical integrity of the fuel bundle, riser, and jumper system was satisfactory and considered to be of adequate design. No significant vibrations were noted during the various phases of operation. Average flow distribution in three of the inner tubes showed an average variation of 5 percent from equal distribution. The center and corner tubes were low and the side tube was high. Maximum deviation, from an equal one, measured 12 percent. Blowout of the flooded fuel bundle was accomplished with dry or significantly wet 1000 psia inlet steam, that steadied out to a minimum flow of 1250 lb/h. Blowout times were estimated at less than a minute for all flows above 1250 lb/h, and times in the vicinity of 2000 lb/h were estimated to be in the order of 5 to 15 seconds. Once the bundle was blown out a flow of 700 lb/h was sufficient to keep the fuel passages clear. This was true even with steam estimated at 10 to 20 percent wet. Flows below 1250 lb/h caused partial blowout. Usually the A tube blew out first and the B and C tubes gradually cleared as flow was increased. Los of flow then caused comparatively sudden flooding ranging from less than 2 to 3 seconds to several minutes for the different tubes within the bundle. Once the bundle was blown out and the flow maintained at more than 700 lb/h, not enough was accumulated – even with very wet steam – to cause sudden flooding of all tubes when flow was cut off. Sudden flooding (i.e., in less than 2 to 3 seconds) occurred only in some tubes within the bundle, while others required times in the order of minutes to flood completely. Heat transfer across the rise steam gap was found to be 12 to 30 times that calculated for a stagnant steam annulus. These results are consistent with estimates of increased heat transfer due to wire wrapping in and annulus and steam circulation. Radial wall temperature drops, at the top and bottom of the rise, varied from 10 to 30 degrees F. Pressure drop data and curves are presented for various segments of the fuel bundle and rise system. Total pressure drop was about 20 percent higher than estimated for saturated steam and was found to vary with the second power of the mass flow, indicating the strong effect of the expansion, contraction, and turn losses

Report (U.S. Atomic Energy Commission)

From abstract: "Thirty-two burnout points were obtained on an electrically heated assembly of 9 simulated fuel rods in a square channel.

Report (U.S. Atomic Energy Commission)

From introduction: "Once-Through boiling of water to 100 per cent steam quality was successfully accomplished. Results of Departure from Nucleate Boiling, transition, and film boiling tests are presented.

Phase velocities in boiling flow systems by total energy and by diffusion /

"Class I."Prepared by General Electric Company, Atomic Power Equipment Department, for the U.S. Atomic Energy Commission."March 1, 1964."Includes bibliographical references (pages 36-37).Mode of access: Internet