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Title: TMI-2 reactor vessel plenum final lift

Abstract

Removal of the plenum assembly from the TMI-2 reactor vessel was necessary to gain access to the core region for defueling. The plenum was lifted from the reactor vessel by the polar crane using three specially designed pendant assemblies. It was then transferred in air to the flooded deep end of the refueling canal and lowered onto a storage stand where it will remain throughout the defueling effort. The lift and transfer were successfully accomplished on May 15, 1985 in just under three hours by a lift team located in a shielded area within the reactor building. The success of the program is attributed to extensive mockup and training activities plus thorough preparations to address potential problems. 54 refs.

Authors:
Publication Date:
Research Org.:
General Public Utilities Nuclear Corp., Middletown, PA (USA)
OSTI Identifier:
6056919
Report Number(s):
GEND-054
ON: DE86005859
DOE Contract Number:
AC07-76ID01570
Resource Type:
Technical Report
Resource Relation:
Other Information: Portions of this document are illegible in microfiche products. Original copy available until stock is exhausted
Country of Publication:
United States
Language:
English
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; THREE MILE ISLAND-2 REACTOR; PRESSURE VESSELS; REPAIR; MOCKUP; PERSONNEL; REACTOR INTERNALS; TRAINING; CONTAINERS; ENRICHED URANIUM REACTORS; POWER REACTORS; PWR TYPE REACTORS; REACTOR COMPONENTS; REACTORS; STRUCTURAL MODELS; THERMAL REACTORS; WATER COOLED REACTORS; WATER MODERATED REACTORS; 210200* - Power Reactors, Nonbreeding, Light-Water Moderated, Nonboiling Water Cooled

Citation Formats

Wilson, D C. TMI-2 reactor vessel plenum final lift. United States: N. p., 1986. Web. doi:10.2172/6056919.
Wilson, D C. TMI-2 reactor vessel plenum final lift. United States. doi:10.2172/6056919.
Wilson, D C. 1986. "TMI-2 reactor vessel plenum final lift". United States. doi:10.2172/6056919. https://www.osti.gov/servlets/purl/6056919.
@article{osti_6056919,
title = {TMI-2 reactor vessel plenum final lift},
author = {Wilson, D C},
abstractNote = {Removal of the plenum assembly from the TMI-2 reactor vessel was necessary to gain access to the core region for defueling. The plenum was lifted from the reactor vessel by the polar crane using three specially designed pendant assemblies. It was then transferred in air to the flooded deep end of the refueling canal and lowered onto a storage stand where it will remain throughout the defueling effort. The lift and transfer were successfully accomplished on May 15, 1985 in just under three hours by a lift team located in a shielded area within the reactor building. The success of the program is attributed to extensive mockup and training activities plus thorough preparations to address potential problems. 54 refs.},
doi = {10.2172/6056919},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1986,
month = 1
}

Technical Report:

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  • A survey was made of sealing methods and their adaptability to the requirements of the plenum reflector seal on the HTGR reactor vessel. A leak rate through the seal of 43.8 pounds per hour of helium was established as an acceptable leak. Lap joints of steel to graphite or graphite to graphite with a 100 RMS surface finish met the required leak rate and two basic concepts of this type of seal are illustrated. (auth)
  • The present work examines the unique heat transfer modeling problems associated with analysis of performance of an upper plenum emergency core cooling injection system during a postulated loss-of-coolant accident (LOCA) in a pressurized water reactor. The particular system under study consists of four 4-inch pipes conveying emergency core cooling water from outside the pressure vessel through four spare control and rod mechanism housings and internal pipings, discharging the water directly over the top of the reactor core. This study is undertaken to examine heat transfer to the emergency core coolant before reaching the core, flow and heat transfer through themore » reactor core, and reflood heat transfer. The phenomena occurring will be delineated and recommendations made for calculating both conservative and best estimate values. The method of solving these problems will be illustrated in a series of examples given in the appendices.« less
  • In-vessel retention (IVR) of core melt is a key severe accident management strategy adopted by some operating nuclear power plants and proposed for some advanced light water reactors (ALWRs). If there were inadequate cooling during a reactor accident, a significant amount of core material could become molten and relocate to the lower head of the reactor vessel, as happened in the Three Mile Island Unit 2 (TMI-2) accident. If it is possible to ensure that the vessel head remains intact so that relocated core materials are retained within the vessel, the enhanced safety associated with these plants can reduce concernsmore » about containment failure and associated risk. For example, the enhanced safety of the Westinghouse Advanced 600 MWe PWR (AP600), which relied upon External Reactor Vessel Cooling (ERVC) for IVR, resulted in the U.S. Nuclear Regulatory Commission (US NRC) approving the design without requiring certain conventional features common to existing LWRs. However, it is not clear that currently proposed external reactor vessel cooling (ERVC) without additional enhancements could provide sufficient heat removal for higher-power reactors (up to 1500 MWe). Hence, a collaborative, three-year, U.S. - Korean International Nuclear Energy Research Initiative (INERI) project was completed in which the Idaho National Engineering and Environmental Laboratory (INEEL), Seoul National University (SNU), Pennsylvania State University (PSU), and the Korea Atomic Energy Research Institute (KAERI) investigated the performance of ERVC and an in-vessel core catcher (IVCC) to determine if IVR is feasible for reactors up to 1500 MWe.« less