ML20235M839
| ML20235M839 | |
| Person / Time | |
|---|---|
| Issue date: | 08/17/1972 |
| From: | Fraley R Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| Shared Package | |
| ML20235M427 | List: |
| References | |
| FOIA-87-40 ACRS-GENERAL, NUDOCS 8707170344 | |
| Download: ML20235M839 (9) | |
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4 I e Honorable John A. McCone 3/14/60
Subject:
Humboldt Bay Power Plant (Note: his Page 3 not part of original letter to Mr. McCone, but attached for ACRS records only.)
ACRS References cont.
U.S. Weather Bureau nnmments on Anendment No. 4, Addandum C, to Preliminn7 Hazards Bunmry Report, dated Ilov. 16, 1959 -
Dec. 3, 1959 U.S. Weather Bureau Cozzents on Addenda A and B to Pr*14minaq Hazards S:mrm y Reprt, dated oct. 15, 1959 U.S. Weather Bureau Coments on Preliminary Hazards Sumary Report, Huy 29, 1959 Following reports received during ACRS Hecting of March 10-12,1960, and distributed during meeting:
l 1) Letter dated Feb. 25, 1960, from the State of I'Mornia, 1
Department of Industrial Relations and a tele $ype dated Feb. 29, 1 1960, from PG&E relating to the Humboldt Bay Reactor Project.
l (rec'd 3/9/60 - in folders), from HEB.
l l 2) "Elast Pressure Analpis" on the Humboldt Bay Power Plant (recid i 3/9/60 - in folders), from HEB.
l l 3) PG&E "Further Remarks on Site Me+eorology, Humboldt Bay Power Plant, Unit No. 3," dta 3/n/60. (ReceivedfromHEBanddistri-buted during meeting Har. 11/1960.)
k) PGLE "he Effect on Dryvell Pressure from Air in Vent Flav,"
dated March 1960. (Received from EEB and distributed during 24thmeeting3/11/60.)
- 5) "Dsffles for Suppression Pool", March 11, 1960 - (Rec'd from PG&E during 24th meeting and distributed 3/n/60.)
- 6) " Testing of Contain::ent Components", March 1960, (Rec'd from PG&E during 24th meeting and distributed 3/n/60.)
$ " Discussion of/ Full Scale Test of Hu=boldt Pressure Suppression Sytem", h rch 1960. (Rec'd from PG&E during 24th meeting and distributed11,/11/60.)
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, 8) " Cal:ulation of Hunboldt Dry Wen Design Pressure by Alternate l 1960. (Rec'd duri.ng 24th meeting from PG&E Method", March3 8,/11/60.)
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August 17, 1972 (
ACRS Members i
PROBLEMS WIThi GERMAN BWRS s
Tne atteched may be of interest. Note damage (leaks) in the suppression chanber of the WUrgassen reactor (page 2) from re-lief valve discharge, and cracks (page 5) in the control rod drive nozzles of the Kahl teactor.
Original signed by R. F. Fraley R. F. Fraley Executive secretary At tach:nent:
AEG Nuclear Reactor Division Information Bulletin, June 1, 1972 cc: J. C. McKinley, w/attmt Circulate 1 copy w/attmt i
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o o Nuclear Reactor Division inforrnation Bulletin A June 1,1972 4
WUrgt an in trouble As reported, the Nuclear Power Station WUrgassen fast Dec.18 had generated witn startup operations its first power. Right through mid-February, the work on the job site aimed at putting the power station into operation, was goisig r>n smoothly and just as planned. All trensient tests performed at loads of up to 75% of rated power, were successful. The behavior of the fuel assemblie.t was ex llent. In neither the water nor the steam, any such activities that could have been specific to a
!cch, acre dntceted.
By the middle of February, however,it was becoming evident for the steam moisture in the live-steam lines to be too high for ranges in excess of 65% of rated power. As a result, the steam <lrying and steam-separating compound was subjected to some design changes whose efficacy had been ascertained in pre-wding investigations on both the air-water test rig of the SteinmUller Compar,y and the steam-water test rig of the AEG Nuclear Laboratoy Grosswetzheim.
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Sectional view of the Wegassen reactor 8 ',
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vent pipes 7, ,
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- 7. Supp'ession-pool water r- -
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- 12. discharge hne -' ,
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o o Moreover, the suppression-pool bottom below the relief valves D9 and D12 had beer, discovered to be dented, a fa:t that was obviously ascribable to the blow-down operations of the valves required as part of the startup-procedures. To preclude such etfects for the future, the bottom plate near the blowdown lines was reinforced by tightly-screwed supporting beams. Af ter completion of the reconstruction and repair work, the plant was started up again on April 11. l Arnong the items which, in the context of power tests run,it about 58% of rated power, were scheduled for checks in the early mornirg hours of April 12, were the relief valves. Af ter three valve D9 actuations, two in succession for 30 seconds each, the third for six minutes, relief valve D10, at 6:14 a.m., took to opening up all by itself, leaving no chance of dropping it from the control l i
room. The instantaneous consanonnee of this was to initiate a slow reactor shutdown by use ollhgrantrol. rods.
l When, at 6.43 a.m., a high water level was identified in the sump of the pres-sure-suppression system, it was decided upon en immediate t eactor shutdown to be brought about by the simultaneous insert;on of all control rods. This measure also caused relief valve D10 to drop. The level chantes in the suppres- I sion pool were clear evidence that it had sprung a leak. As r, first step, the water l was pumped out of the sump back into the suppression pool, to get the sump- ]
water level lowered again.
Di no occasion while the accident lasted, there was any radioa:tivity released j ftom the reactor containment. The radiation level inside the pressure-supores- j sion system was so low as to allow unrestrained access to and insoection of its 1 rooms as early as tuwards noon of April 12.
The instrument charts of the reactor system, the behavior of the piant before j the occurrence of the accident, and the results of both earlier blowdown *.ests j and inspections of the suppression pool admit of an unambiguous conclut. ion l On what caused the damage. I By the blowdown operations of the relief valve D10 over some 30 minutes, us;ng a mass flow of roughly 400 tons of stearn an hour (which would corre-spond to the feed of almost three times the energy amount of the design case),
the suppression-pool's volume of water was gradually being brought into un inadmissible range of temperature (85 to 05 *C). Owing to the pressure paisa- l tions which at such temperatures tend to occur below the open valve, the reinforcing supports required to stabilize the bottom plate were ripped ou~ In this process, about 70 screw holes, each measuring 24 rom across, were ' aid bare, allowing the water to drain from out of the suppression pool down into the sump of the safety containment, n
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Accidents of the nature 45 the one described can be prevented for the future by integrating the measurements of the suppression pool water temperature with a
the safety system, which would provide for an immediate scram, should imper-missible temperatures appear there. As an additional measure to heighten the safety margin against overloads during blowing 4own operations of the relief valves, AEG TELEFUNKEN has proposed to reinforce the lower bottom plate of the suppression pool. The work involved including the repair of the conse-quential damages of the water discharge out of the suppression pool, are esti-mited to take several months.
j The accident, by the way, had no adverse effects whatsoever on eihter the l ,
reactor or the nuclear steam-supply system. The reactor core had never been in danger anyway, since the accident did not have an immediate impact on the systems required for scream operations and heat remova!s. Nor were the operat- k
, iny personnel and the residents of the envirol ment ever exposed to radiation.
1 Briefings High availability rates of the Gundremmingen and Lingen boiling-water reactors l
Af ter their scheduled outage in 1971, the boiling water reactors of the nuclear power stations at Gundremmingen and Lingen have been reaching exquisite l
availability values (temporal availabilities).
Over the months from last Aug.1 through March 31 this year, the serviceability of the nuclear steam supply system of the Gundremmingen Nuclear Power Station was virually unrestricted. The average operative availability of the nveralt plant during the same period of time was 100.9% (Table 1). In November of last year, the power plant had to be shut down for eleven hours because of a necessary repair of a leak in the condenser, and in December for sixteen hours in order to eliminate tap-line porasities (erosions).
While, from last Sept.1 through March 31, the temporal availabili*y of the nuclear steam-supply system of the Lingen Nuclear Power Station was ever-aging 99.4%, the average operative availability of the overall plant stood at 95.9% (Table 2). The slightly lower availabi ity rates were mainly due to inter-ruptions in the conventional part of the olant, Table 1 Temporal a availability of the Gundremmingen SWR Month Temporal availabiht y (Operative availabihty of the nuclear stesm- of the overall plant
. system as %
as %)
AuGJ st.1971 100 100.7 September 1971 100 100.6 October,1971 100 101.6 November 1971 100 99.6 December,1971 100 99.2 January,1972 100 101A Febru ary,1972 100 100.7 March.1972 100 101 A Table 2 Temporal avadability of the Lin9en BWR Month Temporal availabiht y (Operative availabihty of the nuclear steam- ofthe overall plant supply system as % sa %)
September,1971 100 95.2 October.1971 InD 100 Novmber,1971 96.1 91.5 December,1971 99 88.3 January,1972 100 100 February.1971 100 100 March,1972 100 95.9
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. . Redesign cf the Superheat Steam R: actor recommended I It is due to fuel damages, which occured during ths job site activiti:,s aimed at putting the Grosswelzheim Superheat Reactor (HDR) into service, that a l
- I speedy continuation of this work has been thwarted for the time being.
Though, on r/>rinciple, fuel damages could not prevent the HDR concept from being realized,it still had been at issue for quite a while whether, in the face of the wordwide establishment oi 'WRs and PWRs, the HDR construction line is really worth continoiry,.
Now, at its April 20 session, the HDR ad hoc Committee, an advisory body to l the Federal Ministry of Education and Science (BMBW), unanimously opted !
for recommending the reconstruction of the HDR into a light wner test '
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reactor. .
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Af ter its transformation into a bo; ling-water reactor using a conventional super- j heating system in the secondary circuit, the HDR which from its inception had 1 I been designed for experimental operations, would be almost ideally suited for
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the testing of advanced BWR fuel assemblies, especially under lo.ad changes.
Beyond this, innovative components of light-water reactors could be tested. in ether reactors or nuclear power stations, similar experiments have been realiz-able either not at all, or only at substantially higher costs and financial risks (outage times, etc.),
With the HDR-ad-hoc-Committee's recommendatica at hand, it is now .;p to l
l the BMBW to make the finsi decision on the HDR redesign and on the allo-cation of the necessary funds. - A substantial portion of the rebuilding costs l would be raised by interested industries.
l Second license agreement on AEG offgas system :
Af ter Toshiba, the Japanese company, with which a license agreement had been made ,ast year on the AEG offgas system designed for nuciear power stations us;ng boding-water reactors (information Bul'etin Aug. 15,1971, page 4), and which at present is about to furnish three nuclear power staions with it, the j ltalian enterprise Breda Termorneccanica e Locomotive S.p. A. will be the second license of AEG-TE LEFUNKEN's to distribute the of fgas system. An aopropiate preliminary agreement was signed this year on April 17. In the context of a tender which Breda submitted for the Italian 850-MW Nuclear Power Station Caorso, the agreement is already effectual This nuclear power j station will be erected by the f:rms General Electric and Ansaldo, about 30 l kilometers south of Rome.
l The offgas sys'em as offered, which is based on the recombination active-charcoal adsorption principle, a system developed by AEG TELEFUNKEN and successfully tried out at Gundremmingen and Lmgen, will a'so be empicyed in the nuclear power stations at BrunsbUttel, Philhppaburg I and II, Tullnerfeld, lsar, and Krummel. ]
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Fuel reloads for WUrgassen The Preussenelektra last month submitted KWU a letter of intent on the first two fuel reloads for the WUrgassen Nuclear Power Station. The fuel assembiies will be supplied by AEG-TE LEFUNKEN which,in turn, will have them fabri-cated by its subsid;ary, the KRT Kernreaktorteile GmbH, Grosswelzhcim. KRT had also produced the first core load.
The f est reload will consist of a total of 155 fuel assemblies with an average enrichment of 2.60% in U 235, the second of 85 units. The date set for the first partial delive y, will be June 1,1973. An agreement made prnvides that among the fuel assemb!ies to be supplied under the contract, may also be test eternents that are based on a different conception.
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o Leakage on control-rod penetrati n nozzle cf the Kahl reactor i
Af ter a ten years' time of operation of the Kahl reactor, a minor leakage had developed on one of the control-rod penetration nozzles of the reactor pressure l vessel. To be blamed for it was a treverse crack in the circumferential welding joint, caused by a mistake during the welding operations. (The joint's root face )
had not been fully welded through). A similar crack which, though, had not led j to a leakage, was detected on a second penetration nozzle. Both tubes have been removed end replaced with new collar tubes, inserted frorn above and j remotely welded. l Close inspections of the control-rod penetration nozzles had revealed some i 1 longitudinal cracks the cause of which is still being searched into. It is planned I
. :o eliminate the cr6cks by repair and to furnish each of the affected nozzles i with a heat protection pipe.
d The repair work is being done by AEG1ELEFUNKEN,in close coope;ation with the Versuchsalomkraftwerk Kahl GmbH and the Kraf tanlagen AG Heidel- ;
berg. I A leakage of the nature that happened at Kahl could not occur in any of the later pressure vessels (beginning with Gundremmingen), because of their fundamentally different design.
l AEG incore-flux measuring assemblies for Gundremmingen Seven more AEG in-core-flux measuring assemblier : vere delivered fer use in the Gundremmingen reactor. They each are equipped with four MN K 61 miniature ionization chambers and furnished with improved devices for protec- j tion against mechanical impairment of the cables and penetration of moisture during installation. The protective devices were aligned to the special ;
conditions given in the Gundremmingen reactor.
l (Those interested in more details about AEG in-core-flux measuring assemblies and AEG miniature ioriization chambers write to AEG Fachbereich Kern, reaktoren - addrese on back page - for the brochure " Miniature lonization Chambers", No. E 32A.656/0671 E).
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l Arrangement of a in Core Flux Measuring assembiv with Miniature lonaation Chambers within the Reacto: Pressure Vessel e __
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A.B,C,D Mnator 2ongation chambers in vanous core positions 1 Reactor pressure vessel 2 Core dimer.aions 3 Assembly gv+de tube with end isange #- 8 j 4 Protection tube of assembly
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y Reoctor compnents for BrunsbDttel Both mid- and top portion of the reactor pressure vessel arrived at the job site on April 21. They had been conveyed from Italy by sea. All structural require-ments to allow an immediate start of the circular-seam welding between mid-and top portion in the fuel-storage vault, had already been met.
A tentative sssembly of the core internals, such as core shroud, upper and lower core grid plates and core lid, at the Italibn manufacturing plant is scheduled for early June.
The scheme of the axial-pumps production has been timed in such a way as to permit the first pump to be carried this June to Grotswelzheim for a 500-hour test. Later on, sach of the remaining seven axial pumps will be in succession .
subjected to a Grossweizheim 100-hour test.
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The two upper portions of the reactor pressure vessel on arraval at Bronsbutte5 aboard their sfiecial Se8Craf t CO*ning frDrn ltely Nuclear Reactor Division reorganized The recent substantia' business expansion which, especially in 1971, the ,
Nuclear Reactor Division had seen, called for a concentration of elf availabic forces and assign them to AEG boiling-water reactor construction and deve. lop-ment duties. An appropriate intertal reorganization was completed by the ,
beginning of the year.
While. uc to then, the Nuclear Reactor Division had been composed of the several depadments striking separate balances and pursuing varying construc-tion and delivery programs. ;t now has been subdivided into five central groups:
commercial affairs (Laurenze); marketing and projects (Dr. Hundt); develop-ment (Voigt); fue' assemblies (Prof. Dr. Kirchenmayer); reactor building IEngel). Except that the sector " production"has been separated int? the two central groups " fuel essemblies" and " reactor building", this is in conf ormity with the administrative standard scheme.
In terms of organization, the activity in the field of the development of fast-breeding reactors - with its scope somewhat reduced , was assigned to the central group "fue! assemblies" The former " accelerators" department has not been af fected t.y this reorganization.
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l Honorary doctorate for A! fred Schuller j in recognition of the merits which Dipt. Ing. Alfred Schuller, executive
. AEG-TE LEFUNKEN board member and director of the energy-engineering operations of the company, has taken to himself for the evolution of the boiling-water reactor concept and its introduction in the Federal Republic of Germany, the mechanical-engineering f aculty body of the Technical University of Hanover decided to confer on him an honorary degree in engineering science and to promote him to "Dr.-Ing. E.h." (DScl in his eulogy, Prof.Dr.-Ing. Dieter Stegemann, holder of the chair for nuclear engineering, praised the promotee as a provident technician who, in 1957, immediately af ter the ban on any nuclear research operations in Germany was lif ted, started to f rame a nuclear-energy department with AEG.
Alfred Schuller was born in Kronstadt (Siebenb6rgen) on Oct. 3,1911. He attended the Danzig Institute of Technology for the study of electrical engineering sciences and, af ter graduation, went into industry as a young diploma engineer, in 1939, he started his career with AEG. The commission of his to craf t AEG's nuclear-energy department implied at once an attempt at working off arrears in the nuclest field and gaininD Drnond against the leading atomic nations.
This ambitious road is marked by such feats as the technical development of the boiling-water reactor up to economic maturity, the erection of nuclear 1 power stations ranging from the first experimental power station at Kahl on the l Main River (1961) to the projecting of the large-scale Wargassen Nuclear Power i I
Station upon a commercial basis, and the installation of the largest private!*,
om ned complex of nuclear laboratories at Grosswelzheim. 1 The suoject of Dr. Irig E.h. Schuller's address to the audience that had shown up for the ceremony to witness the award o' .he honorary doc
- orate, was on
" Advances in the technology of boiling-water reactors" l I
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AHred Schuller (r.) re<:aiving honorary doctorate diplome from Prof. Dr. J. Wehrmann, recter of ths Hanover Technical University l
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I A E G -TE LE FU N K E N naci ., ae.cio, oi i. ion . e e,.nxiori 7o . AEG-Hochhaus . Telephone (0611) 60D1 1