ACHILLES -Heat Transfer in PWR Core During LOCA Reflood Phase.
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AEA Technology, Winfrith Technology Centre, Dorchester DT2 8DH United Kingdom through the OECD Nuclear Energy Agency Data Bank, Issy-les-Moulineaux, France.
The most important features of the
Achilles rig were the shroud vessel, which contained the test section, and the
downcomer. These may be thought of as representing the core barrel and the
annular downcomer in the reactor pressure vessel.
The test section comprises a cluster of 69 rods in a square array within a
circular shroud vessel. The rod diameter and pitch (9.5 mm and 12.6 mm) were
typical of PWR dimensions. The internal diameter of the shroud vessel was 128
mm. Each rod was electrically heated over a length of 3.66 m, which is typical
of the nuclear heated length in a PWR fuel rod, and each contained 6 internal
thermocouples. These were arranged in one of 8 groupings which concentrated the
thermocouples in different axial zones.
The spacer grids were at prototypic PWR locations. Each grid had two
thermocouples attached to its trailing edge at radial locations. The axial
power profile along the rods was an 11 step approximation to a "chopped
cosine". The shroud vessel had 5 heating zones whose power could be
independently controlled.
The Achilles experiments investigated
the heat transfer in the core of a Pressurized Water Reactor during the re-flood
phase of a postulated large break loss of coolant accident. The results
provided data to validate codes and to improve modeling.
Different types of experiments were carried out which included single phase
cooling, re-flood under low flow conditions, level swell and re-flood under
high flow conditions. Three series of experiments were performed. The first and
the third used the same test section but the second used another test section,
similar in all respects except that it contained a partial blockage formed by
attaching sleeves (or "balloons") to some of the rods.
Phenomena Tested -
Heat transfer in the core of a PWR during a re-flood phase of postulated large
break LOCA.
Test Designation -
Achilles Rig.
The programme includes the following types of experiments:
- on an unballooned cluster:
-- single phase air flow
-- low pressure level swell
-- low flooding rate re-flood
-- high flooding rate re-flood
- on a ballooned cluster containing 80% blockage formed by 16 balloon sleeves
-- single phase air flow
-- low flooding rate re-flood
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Many Computers (M00019MNYCP00).
Included Documentation:
- A. Mason and M.L. Hood, “Data Processing for the Achilles Experiments,” AEEW-R 2321 (March 1991).
- P. Dore and K.G. Pearson, “Achilles Ballooned Cluster Experiments,” AEA-TRS-1060, AEEW-2590.
- K.G. Pearson and M.K. Denham, “Achilles Unballooned Cluster Experiments - Part 1: Description of the Achilles Rig, Test Section and Experimental Procedures,” AEEW-R 2336 (November 1989).
- K.G. Pearson and M.K. Denham, “Achilles Unballooned Cluster Experiments - Part 2: Single Phase Flow Experiments,” AEEW-R 2337 (May 1989).
- K.G. Pearson and M.K. Denham, “Achilles Unballooned Cluster Experiments - Part 3: Low Flooding Rate Reflood Experiments,” AEE2-R 2338 (June 1989).
- K.G. Pearson and M.K. Denham, “Achilles Unballooned Cluster Experiments - Part 4: Low Pressure Level Swell Experiments,” AEEW-R 2339 (June 1989).
- P. Dore and M.K. Denham, “Achilles Unballooned Cluster Experiments - Part 5: Best Estimate Experiments,” AEEW-R 2412 (July 1990).
- P. Dore and D.S. Dhuga, “Achilles Unballooned Cluster Experiments - Part 6: Flow Distribution Experiments,” AEA-RS-1064 (December 1991).
- B.J. Holmes, “ISP 25 Comparison Report,” AEA-TRS-1043 (February 1991) NEA/CSNI/R(91)11.
11. CONTENTS OF LIBRARY
The ACHILLES package contains test data and associated data processing software as well as the documentation listed above.
November 2013.
KEYWORDS: DATABASES, BENCHMARKS, HEAT TRANSFER, LOSS-OF-COLLANT ACCIDENT, PWR REACTORS, REFLOODING