ML20205Q040

Forwards Info Re Intl Conference on Decommissioning of Major Radioactive Facilities on 881011-12 in London

ML20205Q040
Person / Time
Site:	Fort Saint Vrain
Issue date:	11/02/1988
From:	Brey H PUBLIC SERVICE CO. OF COLORADO
To:	Calvo J NRC, NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
P-88367, NUDOCS 8811090056
Download: ML20205Q040 (27)

Text

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Public Service-O*"L-P.o. Box 840 Denver, Co 80201 0840 2420 W. 26th Avenue, Suite 100D, Denver, Colorado 80211

iovember 2,1988 Fort St. Vrain Unit No. 1 P-88367 U. S. Nuclear Regulatory Commission ATTN

Document Control Desk Washington, D.C.

20555 ATTN: Mr. Jose A. Calvo Director, Project Directorate IV Docket No. 50-267

SUBJECT:

INFORMATION RELATED TO INTERNATIONAL CONFERENCE ON DECOMMISSIONING OF MAJOR RADI0 ACTIVE FACILITIES

Dear Mr. Calvo:

During recent NRC-PSC discussions related to the possible decomissioning of Fort St.

Vrain, Mr.

Ken Heitner of the NRC expressed an interest in obtaining additional information related to the international conference on decommissioning that a PSC engineer recently attended.-

The conference was titled "Decomissioning of Pajor Radioactive Facilities", and was conducted in London, U.

K.,

from 11 12 October 1988.

The conference was sponsored by the Institution of Mechanical Engineers.

Attached please find additional infomation related to the conference shich may be of interest to NRC staff members.

Proceedings of the conference may be ordered using the information provided in the attachments.

The PSC engineer who attended the conference found it to be very informative and relevant to current PSC efforts in decommissioning and dismantling.

A trip report highlightir.g the major topics of interest is also provided for your infomation.

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8811090056 881102

( g ADOCKOS00g7 DR

P-88367 Prge 2 November 2,1988 We hope that this information will be of use to you.

Should you desire any additional information related to this internhtional conference or the subject of FSV decommissioning planning, please contact Mr. M. H. Holmes at (303) 480-6960.

Very truly yours ww H. L. Brey, Manager Nuclear Licensing and Resources HLB /MHH:pjb Attachments 1

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INTERNATIONAL CONFERENCE ON DECOMMISSIONING OF MAJOR RADIOACTIVE FACILITIES TRIP REPORT 4

10/10 TO 10/14/88 KEN DVORAK

SUMMARY

4 I recently attended an international conferenca on the

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decommissioning of major radioactive facilities in London England. In addition, I visited a company (Strachan & Henshaw) in l

Bristol England who is designing and constructing the i

decommissioning machine which will be used to dismantle England's gas cooled reactor at Windscale next year.

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In general, it appears most countries are at about the same stage as the USA when it comes to decommissioning. Most of the i

countries do not have a definite plan for their reactors af ter i

J shutdown but are leaning toward delaying dismantling. The only real exception appears to be Japan who is aggressively pursuing 1

immediate dismantlement of their reactors to make room for the construction of future reactors on the same sites due to land availability. Most major countries have or will soon be i

undertaking the dismantling of one or more power reactors as a demonstration that immediate dismantling is possible.

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most of these are demonstrations and the dismantlement of the i

l majority of reactors will be delayed. As a note, the only speake,-

who mentioned using the option of entombment is the speaker from F

DOE who discussed how the DOE has used entombment on several i

facilities.

L It seems other countries, particularly Japan and somewhat the UK, are further ahead of the USA in designing actual remote devices to be used for the complete dismantlement of a reactor vessel, t

The USA does have limited experience however at Shippingport and

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TMI. It appears most countries have the same problems of no l

j locations for the shipment of waste (even more than the USA in

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some cases) but some (such as the UK) are better off as far as i

fuel is concerned since they reprocess their spent fuel. Most other countries are also struggling with how to pay for decommissioning but did not discuss licensing and regulatory i

problems as much as the speakers from the USA.

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MAJOR POINTS OF INTEREST _FROM THE _ CONFERENCE A total of 33 speakers f *;o m several countries presented i

information on various subjects at the conference. All of these talks are detailed in papers prepared by the authors and are included as part of the conference notes which I have a copy. The t

i ft llowing is just a brief highlight of the discussions which were l

of interest to FSV.

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s REACTORS (UK)

The UK is currently in the process of decommissioning the Windscale Advanced Gas-cooled Reactor (WAGR) to Stage 3.

Internationally, Stage 1 is defined as defueling of the reactor and retaining the entire plant on a care and maintenance basis.

Stage 2 is defined as maintaining all radioactive material in a shielded, ventilated and weatherproof enclosure of smallest volume and dismantle and remove all non-acLive buildings and plants.

Stage 3 is defined as completely dismantling and removing the entire plant to release the site for re-use (green-field).

The WAGR was shut down in 1981 and the decision was made to decommission WAGR to Stage 3 to meet the follcwing objectives

-demonstrate feasibility and acceptable costs for dismantling nuclear reactors

-establish a plan and appropriate authorization procedures for the disposal of the active waste

-highlight engineering problems and develop necessary equipment and techniques

-acquire and record info, data and expertise to be ur.ed in design and subsequent decommissioning projects HIGHLIGHTS j

-For the reactor vessel above the hot box level (above the neutron shield) h&da en dismantling will take place l

-Radiation levels of 1 Sv/h (100 Rem /hr) average plus hot spots i

below the hot box dictated remote dismantling

-Remote dismantling is by a machine designed and built by Strachan & Henshaw. The machine has a central mast with remotely controlled manipulator arm via a closed-circuit TV camera. The arm is supplied with various cutting tools and the disassembled components are transferred by a remotely controlled hoist and beam system through a newly constructed shielded waste route into the containers. The cost of the machine is approx. 1/4 of total.

-Defueling complete in 1983, followed by dismantling of the refueling machine and reactor down to the hot box, construction of a waste packaging building and waste route (involved lif ting of the main heat exchangers by 12m), contracting for the machine in 1986 and start of remote operations scheduled for end of 1991.

-Heat exchangers are contaminated due to fuel failure from experiments so investigations are being undertaken on decontamination methods

-Last task would be removal of bioshield (calculations predict and measurements to date confirm less than im of activated concrete) and containment sphere

-Project complete late 1990's at an estimated cost of L,,J0M I

(Approx. $1B). This is high due to the extensivo R&D work and is not expected to reflect future decommissioning projects.

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Cilent United Kingsom Atomic Energy Authenty Function To e smantie the aos anced gas coo.'ed Nuc: ear Reactor and transoct the waste wa a precehned route to a pacmag ag f ac;t ty Ut.hsing tetan remote centret anc e.tp_ seq c rew' T V raw en_sw s**ms-_ _ --

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,' The' system requirements and satty rel ted objectives The system must be capable of safJy dismantling the reactor vessel cnd its contents within th7 beta / gamma radiation, graphite and asbestos particullt; environment. This cnvironment must be both shielded tnd contined t) permit acc:ss at pile cap levelinto specified maintenance areas of the machine.

In the event of failure of any one sub system there are sufficient alternative sub-systems to enable recovery of equipment from the vault area into the shielded maintenance area to permit maintenance activities and rectify the fault.

The structucat integrity for the machine is to be such that failure of a member is oflow probaeitity thus guaranteeing the system a high degree of integrity.

Descriptionof theequipment The decommissioning system compnses two machines: -

The first is the dismantling machine which is mounted at pile cap level and performs dismanthng activities within the reactor vault. The reactor vault is 9.2 metres in diameter and extends downward by 21 metres from the pile cap level.

The second machine is a waste handhng system located within the reactor vault and covent g the transfer routes into the sentencing and maintenance cells adjoining the value, this coverag a being approximately 14 metres. The waste handhng system can operate in conjunction with orindependent of the dismantbng machine, This type of arrangement offers a considerable amount of flexibiktyin operation and limits the dismantling machine payload requirement to the dead weight of the manipulator and tochng, comeined with the dynamic : cads of the dismanthng operations.

The dismantling machine comonses a mast,,olatform, rotating floor shield and containment, all of which is nounted on a heavy duty slewing ring. The whole assemoty weighs approximately 200 tonnes and can be rotated around :he reacter vertical axis to position the platform local to the immediate area of work. The platform is the mounting feature for the work head equipment which comphses of a 6 axis computer ControHed manipulator. 3 c.c t.v. cameras and the cuning tool packages. The services to this equipment are from within the containment via 14 reehng drums. The platform permits easy withdrawal of the manipulator and Cutting tools f or maintenance and tool Changing.

The handhng system supports the waste dunng dismanthng/ cutting and then transports it in one operation, without a change of support, to the storage location within the sentencing ce'l.

A transfer hoist is supported over the reactor via a beam which is in tu rn supported on a slewing ring. This combination of movement permits the hoist to plumb any area of the reactor totally independently of the mast and platform. When waste has been generated within the reactor the transfer hoist transports it into the adjoining sentencing cell where it is subject to assay and monitonng actmties pnor to being stored in baskets or racks. The movement of the hoist within this cell is achieved by use of a centre mounted slewing beam enabnng the noist to cover the whole floor area. The storage baskets and racks are located on a rotating carouset floor thus enabling the operator to position these close to the viewing window in the cell wall.

On completion of rack loading and monitonng activities, the waste hoist is used to lower these through the carousel floor and into the disposal container below.

The control of the system is via 3 interlocked crintrol statens and by totally remote "man in loop" control methods with the aid of c.c.t.v. viewing systems. Sequencing of some operations to ensure interlocking of specific motions is also provided.

The control system utikses 2 channels of etegnty for equipment within the reactor or involved with shielding and containinent. The system uses 3 diverse control processors,1 each for tho dismanthng machine and the waste handhng channet 1 with the tnird for overall channel 2.

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l Etrachan&Henshaw Strachan & Henshaw Limited PO Box 103, Aseton Va:e Road. Brstol BS99 7 TI Enotand Tel. Bnstol(02721664677 Tees 4atm Fau. Bnstol(02'2)f 62605 twan -w

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US-DOE The US-DOE presented decommissioning alternatives, costs, schedules and estimated radiation exposures for the 8 retired Hanford graphite-moderated, water-cooled reactors.

-Since shutdown, each has been placed in safe storage and monitored

-Decommissioning of support facilities; planning begun in 1974, work began in 1976, and to date 25 support f acilities have been decommissioned.

-Alternatives include: 1) Immediate one-piece removal, 2) Safe storage followed be deferred one-piece removal, 3) Safe storage followed be deferred dismantlement and 4) In situ disposal

-Option 1--remove and transport each reactor block intact on a tractor transporter to a specified low level waste disposal facility on the Hanford site. Radiation dose = 20 Rem for one reactor. Time = 12 yr for all 8 reactors 0 $191M.

-Option 2--remove at the end of 75 yr. Radiation dose = 2.9 Rem during storage + 3.5 Rom for removal of one reactor. Time = 75 yr storage + 12 yr for all 8 reactors 0 $198M.

-Option 3-- dismantle after at least 75 yr. Radiation dose =

2.9 Rom during storage + 63.6 Rem for dismantlement for one reactor.

Time = 75 yr storage + 28 yr dismantle for all 8 reactor 0 $217M.

-option 4--prepare and cover the reactor block with a protective mound incorporating engineered barriers. Radiation dose = 5 Rom for one reactor. Time = 6 yr for all 8 reactors 0 $200M.

- An experience data base is being formed including the following new tools and techniques:

large area surface contamination monitor of soil capable of rates up to 1 sq km/hr, remotely operated sand blaster, metal cutting tools including an arc saw for ferrous and non-ferrous materials, concrete scabbler capable of removing up to 2.54 cm of concrete, several low temperature decontamination fluids, a system for electropolishing the interior of tanks and pipes without removing them and high pressure water jets used to cut concrete, steel and ceramic materials.

WEST GERMANY A paper was presented on the tote.1 dismantlement of the Niederaichbach nuclear power plant. It was a 100 MWe heavy water moderated gas cooled pressure tube reactor, which was shut down in 1974 and brought into the state of safe enclosure. The folicw-up decommissioning plan is as follows: 1) Manual in-place dismantling of the non-radioactive systems within the safety containment, 2) Manual removal of the contaminated material, 3)

Remote controlled dismantling of the activated material, 4)

Removal of concrete of the bioshield by explosives and 5)

Conventional demolishing of the buildings. Planning and licensing procedure lasted from 1979 to 1987, with installation of systems in 1987 and completion of entire project in 1994.

REMOTE DISMANTLING OF THE REACTOR CORE:

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-Dose rate was 30 R/hr in 1982

-A crushing house, packing station and shielded control station will be built on the reactor platform to process the waste 3

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-The remote machine is a rotary manipulator used to pick up the separating tools and a manipulator crane to transport the cut off parts to the crushing house. A horizontal slide, vertical mast slide and rotary manipulator allows for the movement (very similar to the WAGR machine).

-Majority of the cutting will be by grinding wheel equipment

-The bio shield will be dismantled by peeling off the wire meshes by precision blasting.

-If steel surface contamination is less than.37 Bq/sq cm and the mass specific activity lower than.37 Bq/g, the metal will be released to a scrap dealer. The contaminated steel will be melted down until the same measured activities are achieved and released as scrap.

-Total waste volume = 130,000t, Rubbish (steel and concrete) =

1 98% of mass, 0% of activity, Contaminated steel for reuse af ter melting = 1% of mass,.1% of activity and Radwaste for final disposal = 1% of mass, 99.9% of activity.

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JAPAN In consideration of future decommissioning of i

commercial power reactors, the Japan Power Demonstration Reactor

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4 (JPDR) decommissioning program has been conducted since 1981.

l Technologies necessary for the reactor dismantling were developed in the first stage of the program. Physical dismantlement of JPDR j

(90 MWt) was initiated in Dec.1986 and cutting performance was i

successfully demonstrated by an underwater plasma arc cutting technique with a robotic manipulator in Feb. of this year. It is expected that 6 yr will be required to dismantle all components i

l and buildings.

-Will take 83x 240 man-days with a total worker exposure of 82.5 man-rem.

Reactor building requires 40% of manpower and i

contributes 80% of exposure. Total waste = 27,800 t, 4100 t of t

radioactive waste.

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-Dismantling technologies developed including mockup tests

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include underwater arc saw for the pressure vessel (up to 250 mm 1

thick cs), underwater plasma are saw for the reactor internals 4

(up to 130 mm thick SST), rotary disk knife for pipe (up to 12" l

sch 80 SST), shaped explosive for pipe (up to 26" sch 80 CS),

diamond saving and coring for concrete bio shield (up to 2.5 sq i

m/hr), abrasive wator jet for concrete bio shield (up to 4 50-600m) and controlled blasting for concrete bio shield (up to.1 l

cu m/hr).

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NETHERLAN9S The reactor vessel, support structure and who:

highly irradiated components at the Petten High Flux Reactor in i

the Netherlands were decommissioned over a period of 7 months as

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part of an extensive upgrading program.

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CONCLUSION's :

-co 60 was the main radionuclide in the activated aluminum and SST

-Careful pre-planning, survey and assessment of radiation levels is a vital part of such a project

-Time is needed for full scale cold mock-up work to prove new equipment and fully develop the man-machine interface

-The reactor staff represent a wealth of detailed knowledge and experience which should not be dispersed before decommissioning, planning and development has been completed

-At no time was airborne contamination a significant problem during size reduction, waste packing or transport.

-The exploitation of under water operation for cutting and dismantling tasks could be applied to many other decommissioning scenarios.

US-DOE The US DOE Remedial Action Programs were identified in the paper and the role of the surplus Facilities Management Program (SFMP) highlighted, including the SFMP long range plan.

The paper focuses on programmatic experience within the SFMP that has influenced program policy, including influences due to environmental compliance and inadequate project planning.

SOME OF THE LESSONS LEARNED

-Success of the Shippingport Project was largely due to the large number of fixed priced contracts that have been awarded equal to or below the original project cost estimate.

-High costs are also a result of situations when contractors are selected and mobilized too early

-DOE has established dose limits of 100 mrem /yr for general public. Release criteria are derived by using realisti: pathway analysis models generated by DOE which are not yet fully endorsed by the EPA. The postponed determination of those limits has delayed project performance. Shippingport procedures and policy j

of the unrestricted release of equ:.pment were not established for 2 yrs after physical decommissioning and the criteria for release l

of bulk materials has yet to be determined. Therefore, all suspect material is assumed to be radioactive waste, increasing burial costs etc. to 400% higher than original estimates.

-It is recommendad to obtain all permits prior to start of decommissioning, including permits from the vaste disposal site to accept all waste to be generated FRANCE An overview of decommissioning was givent

-Excluding national policy or financial interests for the plant owners, there are no technical or safety-related reasons for proceeding with full and immediate dismantling of power plants

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af ter the final shutdown l

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Table 1 $TMF long range plan Eatinated Schedule Cost (Tiscal Year)

Froject Description Location

($1000 US) Start Complete MAJOR PROJECTS Shippingport Station Shippingputt, FA 98 300 1984 1990 Weldon Spring Site St. Charles County, H0 273 547 1986 1993 Battelle Columbus Laboratory Columbus, OH 115 0,00 1983 1997 Total Kajor Projects 446 #e7 BASE FROCRAM Fx0JECTS BY FRIORITY Monticello Vicinity Properties Monticello, UT 4 924 1983 1990 Pbund ANSFD Area s Missisburg, On 45 508 1978 1990 Disposal of Sodius and Lithium

$$TL, Chatsworth, CA 1 322 1983 1990 Cocter for Energy and Environment Research UFR, Ka ya gu e s FR 3 863 1980 1983 Monticello Kill Site Konticello, UT 41 213 1920 1993 SNAP 8 Facility

$$FL, Chatsworth CA 5 553 1978 1992 Homogenous Reactor Experiaant ORNL, Oak Ridge, TN to 620 1986 1995 Esperimental boiling Water Reactor ANL, Argonne, IL 18 650 1986 1994 Molten Salt Reactor Experiment ORNL, Oak Ridge, TN 39 157 1985 1998 3

Ultra High Temperature Experiment LANL, Los Alamos, NH 2 200 1989 1991 i

BORAI V Facility INIL, Idaho Falls ID 2 041 1985 1993 I

SPERT and SOR AI Ancillaries f

Water Boiler Reactor IKEL, Idaho Falls, ID 1 274 1979 1994 LANL, Lo s Al a mo s, KM 1 480 1985 1990 6

LAFRC 11 Reactor Vessel LANL, Lo s Al amo s, NM 75 1990 1990

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Fission Product Filot Plant ORNL, Oak Fidge, TN 1 580 1990 1992 Waste Evaporation Facility ORNL, Oak Ridge, TN 1 230 1990 1991 g

Mound Semi. Works Building Cave Area Mianisburg, OM 2 400 1991 1992 j

Nuclear Development Test Facility SSFL, Chatsworth, CA 4 360 1977 1994 g

Storage Carden ORNL, Oak Ridge, TN 169 1992 1992 i

CRR Experimental Facility Lov Intensity Test Reactor ORNL, Oak Ridge, TN 16 $30 1992 1996 lullding 324 and 325 Mot Cells ORNL, Oak Ridge TN 5 200 1993 1997 FML, Richland WA 26 800 1993 1997 Critical Mass Laboratory FNL, Richland VA 15 000 1993 1997 Heavy Water Component Tesc Reactor SRL, Aiken, SC 17 150 1993 1997 l

Juggernaut Reactor ANL, Argonos, IL 1 255 1933 1994 g

Flutonium Recycle Critical Facility FNL, Richtsnd, WA 470 1993 1994 UC Davis Waste Retention System Davis, CA 745 1993 1994 Radioactive Material Disposal Facility

$$ FL, Chat s worth, CA 2 220 1994 1994 Shielded Transfer Tanks Niagara Falls Storage Site ORNL, Oak Ridge, TN 1 500 1998 1998 Niagara Falls. NY 24 780 1982 1995 Total late Progran Projects 332 290 Managesent and Technical Support 47 834 1978 2000 Completed Projects 11 locations 26 976 1978 1997 Surveillance and Kaintenance 15 locations 40 772 1978 2000 Total Surplus Facilities Kanagement Prograa 934 719 I

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-Although existing means can be considered capable of meeting the

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technical requirements of immediate dismantling, there is ample room for improving them to reduce costs and diminish the doses incurred.

-Most countries are now engaged in decommissioning one or more large power reactors and these are significant test and demonstration projects.

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-Many recommendations were given for cutting tools, decontamination, vaste treatment and conditioning process, remote manipulators, and carriers.

-Virtually all of the existing remotely operated systems in j

France and abroad are based on the use of penetration devices, i

carriers in conjunction with tool holdern. Heavy equipment of l

this type can be paralyzed easily and can not be utilized elsewhere. A system of using several smaller robots consisting of j

modular carriers and defectors of moderate size but cooperating l

J with one another would present significant advantages.

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i DECONTAMINATION Several papers were presented on various aspects of decontamination including the following t

-(UK) Development of reagents for the decontamination of l

stainless steel plant scrap by bulk dissolution

-(UK) Decontamination processes can be used to some benefit in decommissioning projects but not in every case. The principles for selecting a decontamination process are discussed in the paper. Developments in waste disposal policy will govern the future for decontamination and the part it has to play in optimizing the volumes of radioactive l

decommissioning wastes produced.

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-(FRANCE)

An example of power reactor cooling circuit f

decontamination t

-(UK) Decontamination of Magnox boilers i

-(WEST GERNAMY) Decontamination of systems and components for decommissioning--15 tons of replaced piping and valves for a BWR were decontaminated from initial contact dose rate of l

30.000 EE-6 Sv/hr (30,000 mrem /hr) to 1-2 EE-6 Sv/hr (1-2 mrem /hr) which enabled unrestricted release to be easily met.

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-(USA-Davy McKee Muclear Ltd.)

Chemical decontamination 5

for decommissioning I will not go into the above in dstall but the papars presented i

are part of the conference notes, i

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WASTE J

I did not attend this session (attended the session on remote handling instead) but papers were presented on the following subjects:

-(UK) The development of a packaging and disposal system for the Windscale advanced gas-cooled reactor

-(FRANCE)

French processes for waste embedding-the use of l

epoxy resin for waste containment

-(UK) The packaging and transport of large items of intermediate and low level decommissioning waste 1

-(UK) Packaging and transport of decommissioning waste l

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DEVELOPMENT (JAPAN)

A series of experiments on thermic lance cutting method were carried out to obtain useful data for the purpose of making practical application of this method to the dismantling of reinforced concrete. In a lance bar cutting method, one of the thermic methods, the lance bar itself is burnt by heating the tip of the bar with oxygen gas supplied in the lance bar.

The resultant reaction heat of oxidation of iron and aluminum melta, bores and cuts reinforced concrete.

Tests demonstrated the lance bar works both manually and automatically. It is confirmed that the method is applicable to concrete structures reinforced with large diameter steel bars and lined with thick steel plate. Satisfactory cutting of a block is i

done by the remote-controlled method and it is highly possible that this method could be applied to cutting reactor and other concrete structures. Future improvements include greater thermal resistance of the machine, so as to endure the heat generated during the cutting work and to devolep a highly efficient system for disposing and treating fumes c.nd slag generated during the work.

(UK) The development program for the decommissioning of the WAGR was discussed including the following areas:

ESTIMATION OF PLANT RADIOACTIVE INVENTORY

-Information for the following was acquired potential sources, nuclear data, operational data, and material composition

-Computer codes were developed which use the above data to predict activation inventories and their decay with time

-Variation in material composition and trace elements was a major source of potential error in the calculations. A selective 1

sampling program was used to assess the accuracy. TMs has shown so far the spread of Co in the pressure vessel top doma steel of j

100 to 270 ppm.

TECHNIQUES FOR DISMANTING PLANT

-Items to be cut up include the hot box, the pressure vessel and the diagrid, i

-Items to be appropriately detached and lifted clear of the vessel include neutron shield, graphite core blocks and mild steel thermal shield (these are segmented already)

-Mechanical (saws or abrasive discs) and thermal (gas combustion or plasma arc) cutting methods were reviewed

-Problems with mechanical cutting: time required and provision of

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coolant / lubricant if cutting time is decreased, and remote i

control of the large and varying reaction forces developed and the susceptibility to jamming and the recovery problems.

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-Gas cooled plasma torch cutting will be used most often.

Injection of iron / aluminum powder into the flame using nitrogen is being investigated for improving cutting capabilities and enable it to cut SST. This however considerably increases the amount of fume produced and will thus be minimized.

REMOTE OPNRATIONS ROBOTICS AND GRABS

-General procedure for removal of pieces from the reactor is selecting a suitable grab for use on the hoist, attach the grab to the item, free the item from the reactor and transport it to a 1

waste disposal container.

-Design parameters includes remote operator control in both the

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world and tool coordinate systems, ability to teach sequences, j

radiation tolerance, ease of decontamination, payload capability j

of 35 kg (77 f), total weight less than 1 ton and reliable

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REMOTE VIEWING SYSTEMS I

i VENTILATION AND FILTRATION

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-HEPA filters with pre-filters 7

MONITORING AND ASSAY OF ACTIVE MATERIAL t

-Mass determined by transfer hoist loadcoll

-Computer based codes are being developed to interpret the total gamma radiation field data at the surface of scrap items obtained from on line fixed geometry ion chamber readings. These codes J

will use the material composition data obtained from solid sampling to produce the required waste package inventory l

information. Remote techniques for solid sampling using drills j

and shaving sample collection are under development.

I DECONTAMINATION TECHNIQUES

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-Decontamination of the WAGR heat exchangers is being researched for removal of the plateout Cs and cobalt. Adequate DF can be achieved with either hydrochloric or nitric acids.

WASTE PACFAGING AND MANAGEMENT, RECYCLING OF MATERIALS, EXPOSURE REDUCTION AND SAFETY AND RECOMMENDATIONS ON DESIGN To EASE l

DECOMMISSIONING

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4 REMOTE HANDLING (FRANCE)

The paper presents a new manipulator under development 1

in France named RD 500. Main design characteristics include:

-6 degrees of freedom

-sealed water tight rigid metallic casings

-maximum payload of 500 Newtons (112#)

-Speed of.5 m/s

-absolute accuracy of 1 mm

-force and shock control

-reliable, with design of 2000 hrs MTBF, I

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(JAPAN)

Remotu cutting systems for dismantlement of steel structures in the Japan power demonstration reactor were covered in more detail. The same methods as discussed earlier were reviewed and include underwater plasma arc cutting, underwater arc saw cutting, rotary disk knife and shaped explosives.

1 (Japan)

Remote cutting systems for dismantlement of Japan power demonstration reactor concrete biologiccl shield were covered in more detail. The same methods as discussed earlier were reviewed i

and include diamond sawing and coring cutting techniques and abrasive-water jet cutting techniques.

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(UK) The engineering design of the WAGR decommissioning machine

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and robotic manipulator was discussed its more detail. These i

details can be found in the conference papers and are not a

discussed further here.

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4 Fig 2 R D 500 prototype after delivery at CE A

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l OVERVIEW t

(UK)

-It is concluded that the UK nuclear industry has adopted a policy of deferred decommissioning, that is delaying the process of complete dismantlement of radioactive components and assemblies for at least 100 years. This is due in part to the necessity to develop efficient remote handling equipment and there is considerable radiological benefit in deferring operations while radioactive decay occurs.

-The graphite moderation and gas-cooled features dictate very 3

large reactor pressure vessels and gas circuits complicating decommissioning

-The fixed state graphite moderator must remain in-situ within the RPV until the final stage, whereas light water moderators may be drained and treated

-The on -load refueling feature of the Magnox and AGR significantly adds to the dif ficulty of dismantling the highly active core and RPV (due to small refueling penetrations instead of open top like the water plants)

-Stage 1 removal of the irradiated fuel is likely to proceed at a leisurely rate over a period of 4-5 yrs due to fuel handling equipment design rates and the rate at which the fuel flasks can be loaded and shipped to British Nuclear Fuels (BNFL) and the capability of this facility to reprocess the irradiated fuel. (As a note, the reprocessing f acility is being overloaded so it is almost certain the UK will build a dry storage facility in the l

near future)

-Stage 2 may be fragmented with certain vaste removal being completed before the reactor is closed down, and dismantling certain activated components being delayea for decay reasons.

i This stage has also been frustrated by the auspension of sea 1

l dumping of radioactive waste packages, a route previously

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considered for the disposal of large asse blies.

-Stage 3 operations, that is the dismantlement of the reactor components, are likely to be delayed for several decades, if not I

more than 100 yrs.

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-UK 1981/82 cost estimates range between L 250M and L 150M, decreasing with the length of delay assumed before commencing the 4

final stage. These costs estimates were however based on sea

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dumping and land disposal in shallow land repositories for low and intermediate level waste which was also recently withdrawn (it appears the UK will and up disposing of all levels of vaste in deep repositories).

-Designers of future reactor systems need to address the task of l

safe and economic <tecommissioning at the initial design concept and detailing stages.

l (USA)

-It was the opinion of the speaker from DOE that most power reactors will use the 60 yr SAFSTOR period and delay dismantling.

4 11

(JAPAN)

-The philosophy of Japan is that in order to support an ongoing nuclear program with the limitations on land availability, the shutdown reactors will be immediately dismantled to allow for the construction of new reactors on the same fully licensed sites.

(FRANCE)

-When asked what the overall philosophy of France was, the l

indication is that no decision has been mar.e. However, from the indications of the talks, it appears they are also leaning toward i

delayed dismantlement.

(GERMANY)

-In Germany, it is the decision of each plant owner what to do 3

with the site. The speaker indicated that most will probably lean d

toward delayed dismantlement but emphasized that there may be i

i incentive for some to immediately dismantle to reduce the requirements for surveillances of the site during storage.

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f INTERNATIONAL CONFERENCE ON o

DECOMMISSIONING OF MAJOR RADIOACTIVE FACILITIES i

11-12 October 1988 ROYAL LANCASTER HOTEL, LONDON i

SPONSORED BY:

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The Power Industrieu Division l

of IMecht l

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PLANNING PANEL Dr H Lawton (Chairman)

Mr J H Floyd Mr A R Gregory Prufessor J R A Lakey j

Mr C O'Tallanhain t

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Mr P E Vickery 1

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HNIEFING MEETINGS These wi11 be held in the Hediterranean Har ei.i the Iie nt f l e.eir eif the hotel at the following timest Tuesday 11 October

- 08.45 houts Wednesday 12 October 08.I's hours it is very important for all Prenenting Authorn. Keynote SpeatrerH and Gennion Chairmen to attend the appropriate tulefing meetinn on the day of their presentation, if you are unable to at tenut.

I please infose the IHechE stalf at the Conference, or tie f orehand.

so alternative arrangements can be made.

l QQNIEEEttCE_lLINEE The conference dinner has been arranged on the evening of Tuesday

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11 October at the Royal Lancaster Hotel.

Lancaster Terrace.

3 London.

The nearest underground station is Lancaster Gate.

Mapa l

Will be available at the registration desk.

All delegates are invited and the cost is included in the fee.

Please arrive between 19.00 and 19.3Ohours.

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q ACCONMODATION L

i Overnight acconeodation may tm available at the hotel.

Please quote the conference when booking. Tel: 01 262 6737 Telex: 24822 i

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GEttEML SALLO1_CONLEKEtfGE VQLUME i

Volumes of papers will be available for purchase during the Conference.

Volumes may also be purchased' af ter the Conference by non-delegates, or by delegates requiring additional sets from f

the I ns t i tu t i c: s's publishing company at the address and at the j

price given below.

Alternatively. the appropriate section of the j

registration fore may be comp!.,ted and returned.

Mechanica1 Engineerins Pubt icat tons (MEPl P O Box 24 Northgate Avenue Bury St Edmunde Suffolk IP32 69W Te1: 0284 763277 UK E64.00 The Aserleas

$148.00 F.lsewhere C85.00 4

1 EU11011 TONS

)

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The following companies will be exhibiting in the Foyer of the Nine Kings Suite and in the Derby and Richmond Suites throughout 1

the conferencet

DAY ONE - Tuesday 11 October 1988 i

SESSION 1: RE ACTORS 1 i

9 30 Operdng Address: Mr J G Comer, Che6tman UKAEA l

CHANWAAN: Proeessor J R A Lahey, D6eector, Dept Nuclear Schnce and Technology, Royal l

NovelCatege, Greenetch, in the reactor session, progress eli be reported on sin protects, Iwo in Ihe USA, and one eoch in f

l the UK, Germany, Japan and Homand. France's lotecnoet empert mil speak on progeass j

generany m two counsry.

945 N:n-

• _J:-Og WAGR, D9menstration Pre $ect ter UK Reacters by Mr P J Thomas, Research Manager, Decomstwansoneng Group, UKAE A Northern Renegec i

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Laboretones, Mr A R Geogory Head of Nucteet Nm::':= ng Propect GD & CD, CEGB, i

l Mr T Boorman, Pnncipal Propect Eng6neer, WM3R Decommesasoneng, Northern Research

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j Laboretones(W6ndsca6e).

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10 00 The Decommise6ening of Eight Graphete-toederated Reacters

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by Mr H F Daugherty, Mana0er Surp6ue Facet 6es Management, Weehnghouse Hantord Company, Urweed Sietes, Mr C E Miller Jr D6 rector, SF Programme, Rachland Operassons Ottice, 1

l US Department of Energy, Uruted States j

10 15 The heel D6ement6ement of the Niedeve6chhech Nucteet Power Plant (KKN) l by Dr U Looechhorn, Prc$ect Manager, Marneorschungszentrum Karlsruhe West Germany C4 rogramme I

l 10 30 JPOR N::1? ':

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by Mr M Tanaka, General Manager, Decommisatonmg Laboralory, Dept JPDR, Japan Alomic Energy Reeeerch insedute, Japan 1

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10 45 The Deementeng of Act6ve Plant et the Potten High Flum Reactor

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by Mr J A Cothe-Smith, GEC Energy Systems, M R Cundy, JRC Potten, R J Swanenburg, ECN Penen.

11 00 Conee 1

sESS60N 2: REACTORS 2 l

CHANWAAN: Pseesseet J R A Lahey, Dhector, Dept Nuclear Science and Technetegy, Reyel Novel i

Cemego, Osoomsteh, i

I 11 30 Doessendosionang Psegram 5 y :.t : - by the U.S. Department of Energy's Surpeue Ph'eBelseleonagement Program I

by Mr W E Murphes, Program Manager, Surp6us Facierties Management Program U S l

Departeners of Energy, U S A l

1145 h::1. '::':is of 5 Geogemott Reeeerch Reacter i

by Mr R G Strues, Asassaant Dwoctor bor Opetessons Ames Laboratory - USOOF U S A l

12 00 WAGR Ceve Reetse6nt Band Removed I

by Mr H Cacentoy Seneor Devosopment Engmeet, UKAE A W6ndscale Nuclear Labovslotin i

12 15 Reactees C+::- - "n':2,g Gelned Emportance - Futuee Dende by Mr A Cregut. Centre d' Etudes Nuc6eastes. CE A. France

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PROVISION AL PROGR AMME (subject to revision)

SESSION 3: Pt. ANT 1 CH AIRMAN: Mr AR Gregory, Head of Nuclear Decen.2::':{#4 Pregoct, O D & C l

in Ihe plant sessoon work well be deactbed on hvo mimed plutonium uterwum the UK a reprocessing pie <W in Behpum, and a disused peutonium plant at Andermoston Dece. C:':--#4 of a Mised Ouldo Fuel Fabricetten Fac4IRy t4 30 by Mr A Co6 uhoun, Maruget Decommissaoning, Mr S Buck, Plent Manager 9

Bntish Nuclear Fue6s p6c.

PlantetOsamed, l

he.-. '::":.#g Protect of the former Eurochemic 7:;;;;: 14 i

14 50 Be4g6um by Mr J Clees, DogxAy Manager, Mr L Geons Head of Process & D6eme i

l Meyers, Maneget, De690 process, Bekpum.

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Planning and C;;. AM Esp.has of C+::.n. L ":. Aq Deneuronic Contem6no6ed 15 to Facellfles et AWRE Aldennoston by Mr S A Flook, Decommissaoning Manager, AWE MOO (PE), Mr H Downs

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AWE MOO (A).

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15 30 Toa 1

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I SESSION 4: Pt. ANT 2 CH AIMe8AN: Mr A R Gregory, Hood of Nucteer Decommeentoning Pre $ect 00 & CD, CEOS 1

i Mc. cl::':24 n e R$0X Fuoi Fabrication Plcnt i

16 00 by Ing J Deoutens, Deportemert Tscheweche 06euseon Be6gonucteeiro, Solg6 urn Nxteer Deca T2 :":.Og - Pract6cas Esec.has of the Pvtvete Sector 16 20 by Mr A W Beant. Opeest6ons Manager, WesseChem Ltd 16 40 Discussion 1700 End of Sessions Day One 19 00 Conference Dinnet i

Royallancaster Hode4,Lancaster Terrace, London l

De Ian Preston, Deputy Chairman, SSEB to give Confessi,ce Dinner Address Or f rench President of IMechE to we6come guests l

DAY TWO - Wednoedcy 12 October 1988 SES$lON 5A: DECONTAMINAllON CHA4RMAN: ter P E V6chery, Techn6 cal Deportament, Battleh Nuc6 ear Fuele Limited It is wideey recognised that it is chen best to decontamenete plant be6ote decommesseoning it Progress in thes area wel be reported from the USA, UM, France and Getmany Of par 16cular interest m44 be the CEG8's paper rolesing to the boders of theet magnon reactors i

1 9 00 h;:":; r4 of Reagente for the Decentemene46on of Ste6niees Steel Ment Scrap by Suak i

D6esehselon j

by Dr D A Whee, Lectutet, Dept of Chemecal E nginoring, impenal C<":p 9 15 The Appucetten of Decentemenet6on to Decemndee6on6ng Contracte by Mr M J Grove, Operosens Manager, NEl internessonal R&D Co Ltd 930 An Esempte of Posser Reector Coetng Cbcuel Decentembe46en i

by Mr M Monolose, Conste d' Etudes Nucteneros, CEA. France 9d5 4

Dooontendneuen of RW: 3eiters by Dr D Bradbury, SedWelead, Dr C Kittyy, Dr M G Segal, Dr W J Wilkams, Research Othcors, 4

j Bertie6ey Nuc6 ear LGvAines, CEOS 1000 Decentemeneteen and M:m"::':24 et a Fuel F:;:::: :' 4 Phot Plant" by Mr W F Heane, Manager, WestMghouse Deconsermneten & Decommessioneng, Mr D R Speer, Manager, Decantemenes6on and Decomtmaammng Engineering, Wesonghouse, j

Hentoed Co, United States 10 15 Decentendneteenof systemsandc:a::ua terDeccc '::':=4 by Dr lne H O Wine, Depilng H O Berthoedt, Senior Superwoors, OB - Kwu, Seemens AG, West

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1 1030 Chondeel Dosentendnetten let M :n ': :': 14 by Mr M L Shelton, Procese ":

=, Mr M J Ptech, Semot Process Engineet, Devy McKee Nucteer th$

1 10 45 Conee 11 15 Deecuesen i

SES$40N EA: DEVFvDPteENT CHANWAAN: Ak J Hart, Head of Nucteer Es@:: 2, GD & CD, CEOS, Gesucester 4

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Chenongs.C. :':(-Tae problems remain to be soeved Btdish and Japanese papers well be discussed t

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l t145 Empertanenesi Shady ser Me of Therm 6c Lance Cutt 6ng etethod l

by Mr Y Ketano, "r -y Structural Technology. Nuclear Devoeopment Dmsaon. Kumegai Gum.

Co Ltd, Mr N Machede. Nuclear b.r$T,emi Dmsaon, Kumages Gun Co Ltd. Mr Y Kameya, J

i Nuc6eer 6. : %Two Dmason, Kumages Guma Co L td. Japan i

12 00 UKAEA b;:':;- r4 Programmie ter the Decomedee6on6ng o4 the W6ndece6e Advanced l

Geodested Reactor try Mr E H Peracet, Semot Engsneet. Decommeasacnng Group. Dr J R Waketio6d. Principal Eng.neer. Decommasaorang Group, UKAE A Windscane Nuclear Laboratories

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12 15 Discussion

SESSION 50: WASTE CHAIRM AN: Mr C O'Ta44amhain, NNC Lle, Chechere Hygienec handling of waste from decommissaoning activities is vdal. Important papers have been ONeted f rom the UKAE A and f rom NIRE X in assoctahon vnth the CEGB. An innovative French techneque is also lo be descrebed The Development of a Packaging and D6eposal System ter Windecate Advanced G%

9 00

,) cooted Reactot by Mr R Beddows, Decommisanwng Group, Dr R M, Princ,ipal Engmor.

Decommasseoning Group, UKAEA Windscale Nuclear Laboratories 9 15 The French Process tor Weste EmL;Jding in a Thermoeotting Poeymer by Mr P Lourme Decommisa6on6ng Branch Manager, Mr T Sala, Radwaste Department Manager. M' ' C Gauthey, P rocers Engineer, Mr X % gust 6n, Project Manager, Technicasome, France 9 30 The Peck ieg and firenaport of Large home of intermediate and Leur Lnvel Decomndeelon4ng Westes by Mr D Bennett, UK Nitex Ltd, Mr G Holt, Seneor Engineer, CEG8 945 Packaging and firenaport of Decommissioning Weste by Mr C J Mil 6oy, Senior Engineer, Mr J C Mdes, Ove Arup & Partnee s Mr M S Prze, Aaornec

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Enstgy Eatablishment 1

10 00 Discupon 1045 Codee i

l SESSION 88: REMOTE HANOLING CH AIRM AN: Mr J H Floyd, Manag6ng D4 rector, Strachon and."enehmer Decommisseoning must of necessaty be ca:ned out remose6y Equipment has to be rugged, rokable and, il possab4e, made robouc Detaded papers on French, Japenose and British machenery are oNored RD 500 TelemerL 2a=: An equipment under i;:":--;ma in France 11 15 7

by Mr A Cregut, CerWre d' Etudes Nucleastos, CEA, France 11 30 Reinote Cutilng Syenems tor Diementlement of JPOR Steel Structures by Mr H Gohda, Department of JPDR, Japan A&omic Energy Resea ch Institute, Japari Ramole Cutting Systema lor D4ementlement of JPOR Concrete 56olog6 cal Shised 1145 by Mr H Nakamura, Departrc,JrW of JPOH, Japan A4orme Energy Research inalitute, Japan 12 00 Engineering Design of the WAGA Decommisaicnont Mechene and Robo 46c Mer.';zLW by Mr P K i Smith, Group Manager. Taylor Hiloc Ltd Mr E H Perrott, Senior Engeneer, Mr A R F roeman. Ps mcipal E ngineer Decommissioning Group. UKAE A Windscale Laboratori,es 12 15 Discusson L..

DAY TWO - Wednesday 12 October 1988 (Cont)

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SESSION 7: PLEN ARY - TECHNICAL DIFFICULTIES CH AIMMAN: Mr A R Gregory, Head of Nuclear Decommiesioning ProWt, GD & CD, CEG8.

In the final plenary sesson, two papers wHI be presented, one highlighting some of the, technical )

diff6cutties, and the other describing lor the first time the problems of decomn'issioning Ihe Windd piles and how they are being tackled.

l 14.15 Decommteston6ng of Ma$or Medioecttve Fecl#ttes by Mr J H Large, Consuming Engineer, Large & Associates i

1430 The Windecele PHee by Mr J M Jones, Head of Er$,::is DMs6on, Northern Research Laboratories - Windecele 14 45 D6scusskm 1

SESSKMt 8: MNEL DISCUSSION Ct4 AIRMAN: Dr H Lawton, Cheerman of the rienning Penet, formetty Head of Laboratories, Windecolo, UMAEA, 15.05 An internet6onal penet wHI d6scuse a select %n of topics raised throughout the confererv:e names of the penet members wH4 be announced in the final programme 16.15 Closing Romerks: Dr H Lawton 16.30 Tee and close of Conference l

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