ML20155F063

Summary of Advisory Committee on Nuclear Waste 3rd Meeting on 880803-05

ML20155F063
Person / Time
Issue date:	10/04/1988
From:	NRC ADVISORY COMMITTEE ON NUCLEAR WASTE (ACNW)
To:	NRC ADVISORY COMMITTEE ON NUCLEAR WASTE (ACNW)
References
NACNUCLE-R-0003, NUDOCS 8810130111
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TABLE OF CONTENTS THIRD ACNW MEETING HINUTES AUGUST 3-5, 1988

!. C ha i ma n ' s R e po r t ( 0 pe n ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 II. Site Visits to Barnwell and Chem-Nuclear Systems Inc. (0 pen)...... 1 III. Si te Visit to the DOE Savannah River Plant (0 pen). . . . . . . . . . . . . . . . . . 3 IV. SiteVisittoLNTechnologies(0 pen)............................... 4 V. Ex ecu ti ve S es s i o n ( 0pe n ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 A. Future Activities.............................................. 6 B. Reports, Letters and Memoranda................................. 7

1. ACNW Coments on Proposed Branch Technical Position Concerning Environmental Monitorin Waste Disposal Facilities.........g ........................ for Low-Level 7

2. ACNW Coments on Proposed Commission Policy Statement on Regulatory Control Exemptions for Practices Whose Public Health and Safet Concern................y Impacts are Below Regulatory

................................... 7 C.

Othe r Comi ttee Concl us ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

1. ACNW Membership Nomination ............................... 7

2. Request for Information from DOE on its Development of a Hydrologic Model of the Savannah River Plant Site (0 pen).. 7 l

1 DESICIATED ORIGIIAL Certified By G /I '

SS10130111 881004 FDR ADVCM NACNUCLE R-OOO3 PDC 4 0 t t

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it i I APPENDICES  !

THIRD ACNW MEETING MINUTES t i AUGUST 3-5, 1988 i

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I. Attendees '

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]  !!. Future Agenda L 4

I i 111. SupplementaryReportonHDPEHICMaterials(Revision 1),

j dated August 2,1988, Chem-Nucle!" Systers, Inc.

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Federal Regist:r l' Vet. 53, No.148'/ Tuesday August 2,1988 / Notices 29093

• • ofthe Environmental Assessment The original operating license allowed or greater environmentalimpacts need i . single loop operation up to a 50% power not be evaluated.

/dentification of fmposed Action Qvarda leve! for the duration of the operating The principal attemative would be to The proposed amendment would license. When mechanical problems ueny the requested amendment. Denial

P'" revise Technical Specifications section

• • with one recirculstion pump made it of the reauest would result in 2.2 "Umiting Safety System Settings", evident that the unit would operate for intermittent stopping of plant operation ang section 3/4.2 "Power Distnbution an extended period with just cne pump. while the recirculation pump is being Limits", section 3/4.3.6 "Control Rod the licensee performed an analysis serviced. lfowever comparable Diock Instrumentation",3/4.4.1 Reactor which showed that the unit could environmentalimpacts would be Coolant System Recirculation System", operate safely at a power level higher assc.clated with the generation of kOO and associated bases to incorpnrate than 50% with one pump. This analysis replacement power at an alternative 1984. limits applicable to operation of 3e unit looked only at the early years of station location.

e up to 75% power with one recirculatiun operation, extending to an average fuel n, pump unavailable to a fuel bumup of bumup of 15.000 MWD /MT,The license Ahernative Use of /fesources m g,. 35.000 MWD /MT. was amended to all I herpower This action does not involve the use of ee it would also divide section 3/4.3.10 operation with a sing e pump but was any resources not previously considered the "Neutron Flu.x Monitoring restricted to the conditions for wh!ch the in the Final Environmental Statement c,e, Instrumentation"into two parts and safety analysis applied. Related to the Operation of WPPSS ven in relocate the two parts in the Technical Analyses submittedin support of the Nuclear Project No. 2. dated December, specifications. The two new parts would amendment application provide limits 1981.

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ns a 1 ty n 4. eu r$n flux f he\'ta 1o et g al1 o ecti es of A8'###'# ""

Noise Monitors,

1. f esisting technical specifications. The NRC staff revisw3d the licensee's gg The proposed action is in accordance request and did not cons it other Operanon with a single loop will be at a endn ntYa ed hta h 7, reduced power level and is within the agencies or persons.

a as I Finding of no significant impact supplemented by letter dated May 13.

N {0$'onment iNate en elated to the Operation of WPPSS Nuclear Project The Commission has determined not i

The Needfor the Proposed Acrion No. 2. dated December,1991. The to prepare an environmentalimpact The proposed change to the Technical proposed changes do not increase the statement for the proposed license e

Specifications will make it poss!ble to probability or consequences of any amendment.

operate the facility up to 75% power accident. No changes are proposed in Based upon the foregoing 1100 with one of the two recirculation pumps the types of any effluents that rnay be environmental assessment, we conclude nato released offsite, and there is no that the proposed action will not have a

,82- out of service at any time to the end of the station life. Under the current significant increase in 'l e allowable sigtihcant adverse effect on the quality

' th' license, operation with one recirculation individual or cumulatM occupational of the human environment.

pump out of service (called "single loop radiation exposure. Accordingly, the For further details with respect to this O

eperation")is only permitted to a fuel Commission concludes that this action, see the application for M *- amendment da ed March 7,1988 and burnup of 15.000 MWD /MT This burnup proposed action would result in no il"*' les el will be reached in mid 1988, significant radiological environmental supplertwnt de ed May 13.1988 w hlch Without the amendment WNP-2 would impact. are available for public inspection a" m, be required to be shut down if one With regard to potential non- Commission's Public Document Room.

recirculation pump were taken out of t adiologicalimpacts, the proposed 1717 H Street. NW., Washington. DC service. amendment to the Technical ad at the Richland City Library, Swift i Specifications involves only the and Northgate Streets, Richland. j EnvironcrentalImpacts of the Proposed continued operation of systems located Washington. 99352. l Action within the restricted area as defined in Dated at Rockulle Mar >lar.d. thl: 2rth day The Commission has completed its to CFR Part 20. It does not affect non- g %. 3,g evaluation of the proposed revisions to radiological plant effluents and had no For the Lclear Regulatory Cc usion.  !

the Technical Specifications. The other environmental impact. Therefore.

proposed revisions will allow the the Commission concludes that there is

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_ , g, facihty to continue to operate in the es ent that it becomes necessary to take no significant non. radiological environmental impact associated with gg ,p gjg. g ,

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one recirculatiori pump out of service for the proposed ameridment. Em/mn.

testing or for repair.'t he licensee has The Notice of Consideration of (FR Doc. BMr369 Filed 6-1 ea, a H eml estensive espenence with single loop issuance of Amendment and operation gained during the first two Opportunity for Hearing in connection " '*'" "

fuel c>cles because of mechanical with this action was published in the l 13 i. problems with the pumps. Both pumps Federal Register May 10,1988 (U FR dvisory Coenmittee on Nuclear .

C3  % remained in sersice during the third fuel 16605b No request for hearing or petition . Weste; Meeting: Revloed  !

c> cle. Operation with two pumps is for leave to intervene was filed '

preferred bv the licensee because higher following this notice. The Federal Register published {

power production is achievable. Friday. july 15.1988 (53 FR 26915) nt The current limitation on single loop Ahernatin.e to the ProposedAction contamed a nouce of the third meeting F- operation exists because the licensee Since the Commission concluded that of the Advisory Committee on Nuclear lect had not previously evaluated use of a there is eo significant environmental Waste (ACNW) to be held on August single pump at the proposed power level effect that would result from the 3-5.19d On August 3rd the meetmg at later periods in the station hfe, proposed action, alternatises with equal will start at 4.00 p.m. and on August 4th l

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..msm 29094 Federal Register / Vol. 53. No.148 / Tuesday August 2,1988 / Notices

.. C2 at 6.00 p m. at the llolley Inn,235 minimi Ing thea types of inspection (Docket No. 50-4161 s' Richland Avenue and Laurens Street, findings. Incorporation of these key Y System Energy Resources, Inc., et al.;

Aiken. SC. On August 5 the meeting wdl attributes is considered good practice in Y Consideration of issuance of I start at 2 00 p.m. at the Funs Building. the development of a configuration Amendment to Facittty Operating 2000 Dull Street, Room 405 Columbia, management program for nuclear plant ucense and Opportunity for Hearing i SC. Additional topics to be considered i design control' The U.S. Nuclear Regulatory by the Committee include the folloveing: t

1. Letter to the Commission on Dels.v NUREC are available forinspection Commission (the Commission)is ,

Regulatory Concem. at the Commisalon's Public Document considering1:suance of an amendment i

1. Letter to the Commission on the Room.1717 H Street NW., Washington, to Facility Operating Ucense No. NPF- ,

term Anticipated Events and Processes DC. Copies of1: sued NURECs run be 29 issued to Mississippi Power & Ught and Unanticipated Events and purchased from the Government Printing Company, South Mississippi Electric Processes. Office at the current GPO price. Power Association and Cystem Energy

.- 3. Agenda for the 4th ACNW meeting. Information of current GPSLpicas may Re sources. Inc., (the licensees) for September 13-14.1988. be obtained by contacting the operation of the Grand Gulf Nuclear

4. Agenda for the 5th ACNW meeting. Supenntendent of Documenta, U.S. Station (CGNS), Unit 1, located in November 3-4,1988. Govertanent Printing Office. Post Office Claiborne County, Mississippi,

5. Administrativs matters relating to Dos 37082. Washington, DC 20013-7082, The proposed amendment would the scheduling and operating of ACNW telephone (202) 273-2000 or (202) 275- change Attachment 1 to the GGNS Unit 2171. Issued NURECs may also be 1 Operating Ucense by extending the

"".U"fministrative 6A matters relating to implementation dste for a neutron Duit purchased from the National Technical the structure and operation of the Information Ser) ice on a standing order monitor rnesting the requirements of basis. Details on this service may be Regulatory Guide 1.97 tmtil the fourth 1 ther items pertaining to this refueling outage. The presen meeting remained the same as obtained by wnting MIS,5285 Port ,

l n at on t prevtously published. Royal Road, Spnngfield, VA 22161. yp , ehis cheduled to Dated luly 27,196& (5 U.S.C. 552(al) start in February 1989. With the planned Samuel l. Chak. Deted at Rodytlle Maryland this 13th day 18-month fuel cycle, the fourth outage Actmg Admary Commiuse Alanogement of July 1968. would start about August 1990.

• For the Natlear Regulatory Comrnjssion. Prior to issuance of the proposed im Doc Bo-tr3M Fded 8. t-68. &45 am] license amendment, the Commission Brian K Grimes' muma em teso aw will have made findings required by the A ct>rts Director. Division o/Reoctor Atomic Energy Act of1954, as amended &

Ins;'ecten ond SJ eguards. Office o/ Nuclear

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(the Act), and the Commission's i Advisory Committee on Reactor Reactor Resulation. g%

Saf eguards, Subcommittee on TV A (FR Doc. W173?2 Filed 6-1-88. 8 45 am] By September 1,1988, the licensees O gant a lonallssues; Meeting; mm c" "*" may fde a request for a hearing with

- respect toissuance of the amendment to The Federal Register published the subject l'acility operating license and Friday. luly 22,1968 (53 FR 27782) (Docaet No. 50-335) any person whose interest may be contained notice of a meeting of the affected by this proceeding and who ACRS Subcomnuttee on TVA wishes to participate as a party tr' the Florida Power and Ught Co, et at., St.

Organizational Issues scheduled for t.ucle Plant, Unit No.1; Correction to August 5.1988. This meeting has been [r rceeding hearms andmust fde a wntten a petition for leaverequest to Denial of Amendment to Facility

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Operating Ucense and Opportunity for "i ' ""

Dated July 26.1968. E p w,u m Hearin9 filed in accordance with the Commission's "Rules of Practice for i stant Esecuta e D.rectorfer hewt On July 20,1988, the Federal Register Domesuc Ucensmg Proceedings" in 10 published a Notice of Denial of CFR Part 2. lf a request for a heanns or (rR Doc. Wino? Fded 6-t-ea a 45 am Amendment to Facthty Operstmg peution for leas e to interene la filed by

" " * * " " " Ucense and Opportunity for a liearing the above date, the Commission or an for the Flonda Power and Ught Atomic Safety and ucensing Board, HUREQlCR-5147 Fundamental Company, St. Lucae Unit No. l. On page designated by the Commission or by the Attributes of a Configuratkm 27417 of that nouce, second column, fifth Chairman of the Atomic Safe and Management Program for Nuclear paragraph. the date should have been Ueensing Board Panel, wiu e on the Ptnt Design Control; Avaltability August 19,1988. Instead of ]vly 7,1981 request and/or petition, and the Secretary or the designated Atomic The Nuclear Replatory Cowssion Dated Rockville. Marytary, this 25th day Safety and Ucensing Board willissue a gIib -

notice of beenng or an appropriate has published a report the descnbes the For the Nuclur Regulatory Cumnuuion- order.

results of an evaluation of findmes identified dunng a number of NRC F.G. Tourisny. As required by 10 CFK 2.714. a Safety System Functionalinspectic ts Acterg D; rector, hrject D;tectorote ll-2 petition for lease to intervene shall set and Safety fystem Outage Mmidicauen Dmsron of Reactor Proacces-////. Ofice of forth with part4cularity the interest of Inspecuons w hich are related to Nucleor Reactoraryu/ coon. the petitioner in the proceeding, and configuration management. Attnbutes (R doc. so-173?0 Fded 6-1-4& Ass am) how that interest may be effected by the were developed which are responsive to asuwe coce rme-as results of the proceeding The peution

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Federal Register / Vol. 53, No.136 / Friday, July 15, 1988 / Notices 26915 drums but will be overpacked in U.S. Nuclear Regulatory Cornmisalon, during this meeting may be lirnited to stainless steel or geh anized drums. Wa shington, DC 20555. selected portions of the meeting as Needfor the Proposed Action Dated at Rockville. Mar >!and, thl sth day determined by the ACNW Chairman.

Presently hot cell waste is stored in of July.19sa. Information regarding the time to be set For the Nuclear Regdatory Commission. aside for this purpose may be obtelned the Annes of Bu!!dmg i This facihty is by a prepaid telephone call to the full, and the normal operations in 1 Mand C. Rouse' Executive Director of the Office of the support of esisting and anticipated contracts kill generate approximately fd'@lM((','/[j-[',$'#8'l 3y33 ACRS Mr, Raymond F. Fraley, prier to

. the meeting. In view of the possibility

, 10C more drums oser the next 5 )ean. tha1 the achedule for ACNW meetingn This waste is being stored onsite ur t!!it (FR Doc. 66-1575 Filed 714-6a a 45 am)

"* may be adjusted by the Chaltman as is accepted by the Department of Energy *[" '#** necessary to facilitate the conduct of the under the Nucleat Waste Policy Act of meeting, persons planning to attend 1982. Den >ing the construction and use Advisory Committee on Nuclear should check with the ACRS Executive of this facility would completely curtail the normal operations associatrd with Waste; Meeting Director if such rescheduling would result in major incoavenience, the hot cells. The Advisory Committee on Nuclear Dated July 11, nosa.

Enrironmerto!/m;>act of the Preposed Waste (ACNWvill hold its third John C. Ho>le,

" *" meetinh 4th it will meet at 4 DO p m. aton Commiure August Manapment b5,1988.Officer.

On August 3rd an A dvisory Since only dry containerized waste the Ho!!ey Inn. 235 Richland Avenue will be stored in this facih'), there (nt Doc 86 t m4 Filed 714-68. e 45 am) and Laurens Street. Aiken. SC.The sw .ocoo re. m.m should be no effbents produced. Any meetints will be concluded by too p m.

rain or snowmelt that manages to enter on those days On August 5 the meeting the concrete cylinders will automatically will be held in Room 405, Fims Building. (Docket No. 60-4001 drain into the :arrpling pit. This w ster 2600 Bull Street Columbia, SC. On that will be periodically remosed in the day the meeting will start at 2 00 p rn. Carolina Power & Ught Co., Shiaron unhkel) es ent that w ater should and be concluded by 5:00 p.m. The entire Harris Nuclear Power Plant, Unit '.;

penetrate the drums. any Icachate would meeting will be open to the pub!!c. Exemption a pit before now to the radioacta samplinI could enter the M ednesda) August 3,1968 e materia I .

ground w ater. The drums. concrete 4 00p m-7mp.m. '!he Committee w alls. and subterranean location will Carolina Pow er & Light Company (ths will discuss their visits to the 1.LW licensee)is the holder of Facility proside shielding to redace radiation disposal facihty at Barnewell. SC and Operating License No. NPF-63. whkh les els abos e ground to below regulatory the Chem Nuclear operations center, I'"I

authorites operation of the Sheaton Thursday, August 4,1988 Harris Nuclear Power Plant, Unit 1.*3 e Asencies ord persons Consulted There was no contact vith other 4 Np m -7m p m :The Committee will discuss their sielt to the waste gg gg',* ); 0{'g',*,&e

','"'y',P ,'h ,

agencies regulations and Orders of the Nuclea'r handhng and storage facihties at DOE.s Regulatory Commission (the rending of No Sgn$ cant Impact Savannah Rn er Plant.

Commission) now or hereafter in effect.

The Commission has determined not Friday, August 5,1988 gg to prepare an EnvironmentalImpact 700p m.-J 00p m.1The Committee Statement for the proposed action will discuss their sisit to the facihties of Section 103(c)(2) to to CR Part 20 Based upon the Ensironmental LN Technologies and meet with requires a determination by a physician Assessment we conclude that ths representatius of the South Caroline at least once every 12 months that an proposed action will not has e a Bureau of Radiological Health. individualis physically able to use the significant effect on the quahty of he Procedures for the conduct of and respiratory protective equ5 ment !n an human ensironment. The Environ nental participationin ACNW meeHnis were enWonment containing airborne Assessment for the proposed action, on published in the Federal Register on radioactive material, which this Finding of No Significant June 6.1988 (53 FR 20699). In accordance By letter dated january 30,1986, the impact is based. rebes on the Babexk &

with these procedures oral or written licensee requested an exemption from 10 t Wilcox information submitted as statements may be presented by CR 20.101(c)(2) with regard to the l Amendment 4 to License No. SNM-778. members of the public, recordings will interval for the ad:tinistration of a December 8.1987, and the additional be permitted only during those portions physical examination for users of information submitted by B&W on of the meeting when a transcript is being respira tory equipment. Specifically, the March 30.1958 and June 20.1988. kept, and questions may be asked only licensee reques'ed an exemption to The Environrnental Assessment and by members of the Committee.its permit the physicals to be administered the abos e dxuments related to this consul' ants, and Staff. The Office of the at an interval of every 9 to ts months i proposed action are available for pub!!c ACRS is providing Staff support for the rather then the curte.aly scheduled 8 to inspection and copying. for a fee. at the ACNW, Persons destri to make oral 12 months. In support of its request, the Commission's Pubhc Document Room, statements should noti the Ehecutive licensee notes that the exemption would 1717 H Street NW., Washington, DC. Director of the Office the ACRS as far prodde greater flexibihty in schedulms Copies of the Environmental in ads ance as practicable so that of examinations and would preclude the Assessment may be obtained by calling appropriate arrangements can be made need for administration of two (301) 492-0609 or by writHg to the Fuel to allow the necessary time during the examinations tn the same calendar year.

Cy cle Safety Branch. Division of rnetting for such statements. Use of still, The accepatibility of the exemption Industrial and Medical Nuclear Safety, motion picture and television cameras request is dacussed below.

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AGENDA FOR

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ACNH VISIT OF BARNHELL FACILITIES ,

L AUGUST 3, 1988

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00 am . ARRIVAL AND SIGN-IN j 9:30 am CHEM-NUCLEAR'S DRY STORAGE FUEL CASK AND TRANSPORTATION CASK FLEET.

10:00 am BARNWELL HASTE MANAGEMENT FACILITY (

11:15 am ENVIRONMENTAL & DOSIMETRY LABORATORY .

12:00 LUNCH l f l  ;

! 1:00 pm DISPOSAL LINER AND HIGH DENSITY POLYETHYLENE HIGH INTEGRITY CONTAINER OUTFITTING FACILITY. r

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'l 2:00 pm HASTE FORM CERTIFICATION PROGRAM AND TESTING LABORATORY i

i 3:00 pm RAPID DEHATERING SYSTEM (RDS-1000) AND  !

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PREOPERATIONAL TESTING PROGRAM.  :

i 4:00 pm DEPARTURE  !

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SAVANNAHRIVEROPERATIONSOFF.!CE(SR)

AGENDA FOR ADVISORY COMMITTEE ON NUCLEAR WASTE AUGUST 4, 1988 i

7:30 a.m. Neet DOE Representative Lobby of Holley Inn .

7:55 a.m. Arrive at SR, 703A-Lobby ,

8:00 a.m. Welcome to Savannah River Operations i - Overview of SR Waste Management Progra:n for Low-level Waste (LLW). Transuranic Waste (TRU), High-Level Waste (HLW)

- Overview of Defense Waste Processing Facility (DWPF) Project ,

Status

- DWPF Waste Compliance Program Overall Waste Acceptance Process DWPF Process Summary ,

Waste Compliance Program Waste Compliance Specifications l Waste Compliance Plan Waste Oualification Report ,

Quality Assurance Program (0GR/B-14) j - NRC Technical Exchange Meetings j - Relationship with West Valley Demonstration Project '

(Description of Technical Interface / Transfer Efforts) 11:00 a.m. Tour High-Level Caves - Radioactive Research Melter / PCT 4

11:45 a.m. Lunch (Catered in SRL or Cafeteria Conference Room) i 12:45 p.m. Tour LLW Burial Grounds I Tour TRU Waste Tour HLW Tank Fanns 2:00 p.m. Tour Hock-Up Area for Vitrification Process Equipment ,

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i 2:30 p.m. Tour S Area (walk through of Vitrification and Glass i Storage Buildings) ,

l 3:00 p.m Tour Z Area Saltstone Process l 1

3:45 p.m. Tour TNX Area (Equipment / Process Design Demonstration) l

, 5:00 p.m. Depart SR, Return to Aiken, SC 1

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p. yscHNOLOGIE3 ADVISORY COMMITTEE ON NUCLEAR WA8TE VISIT AUGUST 5, 1988 AGENDA

• I. Introduction - G.P. Motl, President 09:30 - 09:40 >

II. Brief History of LN Technologies - G.P. Motl, President 09:40 - 09:50 III. Overview of Services 09:50 - 10:30 A. Radwaste Services - Regan Voit, Vice President, Operations

. 1. Solidification '

2. Quick-Dry Dewatering / Volume Reduction Service

3. TRANSFIX

4. Transportation

5. Liquid Abrasive Decontamination

6. HICs B. Chemical Decontamination Services - Paul Denault, Director, Chemical Decontamination

1. LOMI -

Services

< 2. CANDECON

3. Chem Decon Waste Processing IV. Demonstrations 10:30 - 11:15 A. Radwaste Solidification - Angela Valvasori, Chemical Engineer

1. Preparation of Bead Resin PCP test solidification cup

B. Radwaste Dewatering - Dennis Jones, Director Engineering '

1. Quick-Dry table top demo

2. Quick-Dry full scale video V. Break - 11:15 - 11:25 VI. Regulatory Issues / Status - Regan Voit, Vice President, Operations 11:25 - 11:45 ,

A. 10CFR61 waste form testiJig B. High Integrity containers C. IAEA Transportation Regulations (proposed rule-making)

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fp rscHNOLOGleE .

. t Agenda - Advisory Committee on Nuclear Waste Visit '

August 5, 1988 Page 2 VII. Facility Tour - Dennis Jones, Director Engineering

• j 11:45 - 12:15 o HICs

! . Barrier-55 polyethylene (withdrawn from market)

) . NUHIC-120 polyethylene  !

. Barrier Plus steel / poly hybrid l

o Radwaste Shipping casks o Radwaste solidification unit o Radwaste solidification liners VIII. Lunch - Catered at LN Technologies

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~D 1 HINUTES OF THE 3RD ACNW HEETING b .

bas b AUGUST 3-5, 1988 The 3rd Meeting of the Advisory Committee on Nuclear Waste was convened by Chaiman Dade W. Moeller at 4:30 p.m. on August 3,1988, at the Holley Inn, Aiken, S.C.

[ Note: For a list of attendees, see Appendix !. All ACNW members were present. Dr. C. V. Smith was not in attendance for session IV. herein.]

The Chaiman noted that the agenda for the meeting had been published and identified the items to be discussed. He stated that the meeting was being held in conformance with the Federal Advisory Comittee Act and the Government in the Sunshine Act, Public Laws92-463 and 94-409, respective 1).

[ Note: Dr. S. J. S. Parr sessions of the meeting.]y was the Designated Federal Official for all

1. Chaiman's Report (0 pen) .

Chaiman Dade W. Moeller gave welcoming remarks, described the role and responsibilities of the ACNW and introduced the ACNd members and staff, and noted the presence of NRC staff. Dr. M. Ryan of Chem-Nuclear was then called on to review the day's activities at the Barnwell site and Chem Nuclear facilities.

II. Site Visits to Barnwell and Chem-Nuclear Systems, Inc. (0 pen)

Dr. Pyan focused his remarks on a general rebuttal of the Silling report on high-density polyethylene high integrity containers (HDPE HICs). He provided the Comittee with a copy of Chem-Nuclear's submission to the NRC staff on this topic (Appendix III). With reference to coments made during a provious ACNW meeting, he presented actual data on the radiation 'ield that a HDPE HIC receives on an annua 1 basis. Maximum cumulative dosg over g00 years was cited to be 3 x 107 Rad with an exposure of 10 to 10 Rad considered as "nomal" or average.

It was noted that Dr. Silling had depended on data on linear PE whereas the HDPE is cross-linked. During questioning, it was acknowledged that cross-linked data are not generally available. At this point, Dr.

Malcoln Knapp, Director of the low-level Waste Management and Decomis-sioning Div 'on described the preparation of Dr. Silling's report and the status . N si topical reports relating to HICs.

Dr. Ryan then t.untinued his coments on the Silling report noting that those people cond9cting the analysis had assumed an empty HIC, whereas '

all Hits are required to be at least 85% full, and that no lateral support from compacted backfill was assumed. It was pointed out to Dr.

Ryan that the contents of some HICs would offer little or no mechanical support. He stated that the need for assessing the impact of soil-HIC interactions had been pointed out by BNL investigators in an earlier report on HICs. Dr. Ryan then described an actual buckling test that i

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3RD ACRS MEETING MINUTES 2 Chem-Nuclear perfor.ned. The experimental procedure and results of this test are contained in a proprietary topical report. However, the test did not duplicate actual burial conditions.

1 At this t'me, Mr. Virgil Autry of the South Carolina Bureau of. Radio-logical Control provided some historical perspective on the certifica-tion of H']PE HICs. He noted that in the late 1970's and 1980's no i satisfactory solidification procedures were available and that reliable -

packaging was sought as a replacement for unreliable solidification processes. The absence of guidance from the NRC was noted. As a consequerce South Carolina authorized the use of the HDFZ HICs until more reldable packaging might become available. He noted the need for a

an inert material of construction, because of the humid atmosphere and ,

i suggested that failure of a package should be related to risk to the 1

public. Dr. Ryan suggested that risk to the disposal site worker was a 1

more realistic and imediate concern.  !

l Mr. Autry noted that the wide range of dose rates at the surfaces of the l packages,100 mr to 30,000 R per hour, required the development of added L

!j operational control. He noted that the additional requirement for  !

venting of all HICs is an illustration of the reaction of his office to  ;

j operational problems. '

j Dr. Steindler asked if the 300-year lifetime requirement was for struc-i tural rigidity or penetration. It was indicated that it was not explic-

iti defined, but that the intent was to prevent groundwater contact wit the waste itself, s

Dr. Smith asked what would happen if the 1992 date for site closure was i reached and no new disposal site was available. Mr. Autry indicated  ;

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, that -here is a legislative mandate to keep the site open. '

1 Dr. Moeller raised the question as to the minimum volume of waste

! required to permit economical operation of a site. Mr. Ebenhack of l Chem-Nuclear stated that, assumin a reasonable unit cost (which was 4

unspecified), at least one half m liion cu. ft. per year would be l

. required. In response to further questions, he stated that the ori burial charge had been 50.85 per cu. ft. and wss now $45.00 per cu.ginal ft.

A general discussion on the possible impact of the Amendments Act on I

, public 53fety ensued. It appeared to be a generally accepted point that j

proliferation of LLW disposal sites has the likelihood, if not certain- t ty, of resulting in significant cost increases, reduced waste volumes, l and possibly increased risk to the site workers and/or public, i t

! Mr. W. House of (., hem-Nuclear described a recent incident where a liner l

of solidified resins containing a permissible level of chelating agents was found to be incompletely mixed and partially solidified. The liner  !

I was held at Barnwell, and Grand Gulf, the waste generator, arranged for  !

Chem-Nuclear to overpack the liner, which is a mild steel vessel of l I

1

3RD ACRS MEETING MINUTES 3 limited structural strength, with a duplex stainless steel HIC. Grand Gulf was fined $1000 by the State of South Carolinc for supplying improperly solidified material.

A number of general questions on the day-to day operations of the facility followed. For example, if a shipment doesn't arrive within 60 days of its advance notice, a search is instituted. The Bill of Lading is generally accepted as an inventory of the shipment because of ALARA concerns, and the shipper defines the waste's classification as A. 8. or l i

C. Samples are not tested for biological agents and smoke detectors can be buried. .

Dr. Moeller reconnended adoption o ' the ICRP dose factors in future regulations or guides. Dr. Moeller asked to see certain plans and programs developed for Barnwell. Cam-Nuclear will provide tables of evntents and sumaries of the plans for review but because of their volume, will not send the plans, etc., unless a spe,cific request is received.

!!!. Sjte Visit to the DOE Savannah River Plant (SRP) (0 pen)

The meeting was reconvened by Chairman Moeller at 6:00 p.m. August 4 at the Holley Inn. Aiken. S.C. Dr. Moeller described the purpose of the ACNW, the da 's activities, and introduced the ACNW members and staff and attendin NRC staff.

Dr. Steindler moved that two letters, previously drafted, be .* ully approved by the Comitteet the motion was seconded by Dr. Smith and tiere was unanimous approval. The letters relate to the Branch Technical Position on environmental monitoring at LLW disposal sites and the Below Regulatory Concern (BRC) policy statement.

Mr. D. Fulmer of DOE sumarized the activities of the day and described the various sites visited. Dr. Moeller asked what regulatory agencies interact with DOE in the operation of the several waste handling facil-ities. Mr. Fulmer responded, noting that, for example, since "Salt-stone" is a mixed waste the EPA provides regulatory oveisight on its disposal. [ Note: Saltstone is a mixture of fly ash, cement and the high nitrate residual salts that are left after the principal radioac-tive constituents are removed from the high-level wa te stream.]

Dr. Steindler noted that the operation of the Defense Waste Processing Facility (DWPF) will likely precede that of the repository. He noted that that situation raised the possibility of a mismatch between the output of the DWPF and the acceptability criteria to be imposed at the repository. The DOE staff acknowledged this situation and described. in some detail, their lon; standing and continuing efforts in developing a consensus between the NRC staff and themselves as to what will consti-tute an acceptable product, with suitable process controls.

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3RD ACRS MEETING MINUTES 4 l

l Dr. Moeller asked whether hydrologic models of SRP were being developed. l The DOE staff indicated that such models were in the process of D development and agreed to document for the ACNW the levels of l

expenditures in this area.

! Dr. Steindler inquired whether the TRUPAC packages to be used for l 1 transportation of TRU waste to the WIPP disposal site will be certified i by an outside agency. Mr. Hindran of DOE-HQ stated that the package i

will undergo full NRC certification. It was indicated that the original design was changed at the request of New Mexico officials and that a l new, much more reliable, design was now being tested, j Dr. Smith asked what was the expected rate of shipment of the solidified  !

I glass canisters. It was indicated that one canister at a time would be  !

3 shipped by truck, and up to seven by unitized train. Dr. Smith ques-l i tiened the control of product properties by process control techniques j

] (PCT). SRP personnel acknowledged that this is an ongoing topic of i i discussion with the NRC staff and that SRP will seek additional peer  :

j review. l l

Dr. Moeller requested a description of the experience at SRP in the use l i

of compactors for volume reduction of LLW. SRP personnel indicated that t comercially evallable units that have been modified are in use. It was j noted that not all LLW was compacted, but those materials that were  ;

processed were reduced in voltime by factors of 4 to 6, with an overall t i

annual volume reduction of some 10%. It was mentioned that, while the  !

overall costs of handling LLW at the SRP was some $9 per cu. ft., there  !

are too many differences in the two systems, and associated cost i accounting, for this figure to be compared to comercial disposal fees, i, l The use of incineration processes was questioned by Dr. Moeller. SRP 1

personnel comented that a demonstration unit designed for use with .

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organics was down for modification of the off-gas system due to corro- I sion. However, SRP is authorized to obtain an incinerator to process a l

} consolidated waste stream. It is >1anned to t,e a two-stage system t i designed along the lines of the Oat Ridge toxic waste system. A volume i

) reduction of 20 to 1 is expected. Dr. Steindler comented that chela- j j ting agents can be processed in similar units.

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i Dr. Moeller asked how the Comittee could assist the defense waste  !

!' program. The general response was that improved coasnunication between

] the NRC and the civilian and defense waste programs was needed and that l t

j added support of NRC staff interactions would be helpful.

4 l j The Consnittee adjourned to reconvene on August 5.

IV. SiteVisittoLNTechnologies(0 pen) j -

{

The meeting was reconvened by Chairman Moeller at 2:05 p.m., August 5  ;

} 1988 at the Sims Building, 2600 Bull Street, Coluinbia, S.C. 29201. I

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'O 3RD ACRS MEETINu MINUTES 5 1'

Dr. Moeller gave some opening remarks and thanked Mr. H. Shealy of the South Carolina Bureau of Radiological Health for arranging the meeting facilities. Dr. Steindler, the ACNW staff, and NRC staff members attending were introduced and the meeting comenced with brief welcoming

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remarks by Mr. Realy. Dr. S.nith was not in attendance.

t At the conclusion of Mr. Shealy's comments Dr. Moeller asked whether there were any matters concerning the State that the Comittee might address. While Mr. Shcaly at this time indicated that there were no items of particular concern, Mr. Autry of the Bureau later noted their support for NRC regulatory responsibility over Naturally Occurring and Artificially Produced Radioactive Materials (NARM) and hoped for an early, favorable closure to this matter. In response to questions by i

Dr. Steindler, Mr. Shealy indicated that his laboratory only tested l samples for radiological contamination, not hazardous or biological

components.

1 I Subsequent to these coments, Mr. R. Voit of LN Technologies, Inc. (LN)

1. sumarized the Comittee's visit to LN's facilities. He noted that LN had three major current concerns. These are: 1)highintegritycon-l t41ners (HICs), 2) LLW fonn certification and 3) Part 71 rule changes to provide nutuel conpliance with IAEA regulations.

With respect to HICs, Mr. Voit sumarized LN's experiences with poly-ethylene (PE) HICs, which were abandoned because of unfavorable techni-cal analyses, and PE-lined steel HICs which are the subject of a topical report being reviewed by the NRC staff. The requirerents of 10 CFR 61 i

were reviewed and it was indicated that the associated Branch Technical

' Positions (BTPs) were vague and needed clarification. It was noted that the certification of waste fonns took an inordinate length of time, and

) that there seemed to be a lack of consistency in the criteria or thsir i

interpretation. The fact that NRR is now questioning the generic waste

' fom concept was used as an illustration of the latter point. In l' conclusion, Mr. Voit consrented on the proposed change in Part 71. The changes proposed will bring the NRC regulations into conformance with  ;

the IAEA regulations. However, the changes will also allow the trans-shipment of waste matertals across national boundaries and Mr. Voit  ;

) questioned whether this was an adequate reason for making the '

modifications to the rule.

After discussing these points. Mr. Voit descrit>ed the specific items i i,

that the Committee had inspected during its visit. Included were visual inspection of both metallic lirers and PE-lined HICs, and mobile pro-cessing systees used to deuter class A wastes and to solidify class 5

) wastes. Demonstration of both the dewaterinj and solidification proc- '

esses were given. I l Relative to the Part 71 ch'inges, Dr. Moeller suggested that the rule 1

changes might only apply to shipments between cooperating countries, and that internal shipments would be unaffected. In response to a question

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l 3RD ACRS MEETING MINUTES 6 by Dr. Moeller, it was noted that, sines DOE has to comply with both 10 CFR and 49 CFR parts DOE will meet the IAEA criteria if they are l adopted. This concluded Mr. Voit's presentation.

Mr. Autry of the South Carolina Bureau of Radiological Health then gave a demonstration of the data handling capability of the Bureau, with ,

respect to retrieving infonnation concerning LLW buried at Barnwell. +

Mr. Knapp of the NRC staff asked if site operators should accumulate data on material being buried. Mr. Autry indicated tha: he believed that the generators should develop these data and submit such data on i

the shipping manifest.

1 Dr. Moeller inquired if radium is allowed to be disposed. Mr. Autry

' said it had been, but tha EPA tried to ship all radium waste tc South j Carolina. As a result, South Carolina stopped all disposal u radium, .

which, due to its half-life, is considered akin to TRU.

1 This portion of the meeting was concluded, and a brief tour of the Bureau's facilities was held.

V. ExecutiveSession(0 pen / Closed)  !

The Comittee went into Executive Session on August 3 and 4.

l

] A. Future Activities. (0 pen) l On August 3 the Comittee discussed the agenda for the next two meetings, September 13-14, and November 3-4, 1988.

r For the September meeting, it we agreed that the ACNW staff could '

have up to two hours to discuss administrative r.atters with the

• members. The Comittee agreed that they did not want to discuss l

) DOE's Dry Spent Fuel Storage Cask Study until the NRC was prepared to comment on the finalized DOE report. Topics accepted for 4

presentation include: 1) plant decomissioning guidance, 2) cement-based LLW solidification topical reports, 3) proposed rulemaking I

actions to resolve regulatory ancertainties, 4) DOE's reaction to i NRC staff point papers, 5) Division of LLW plans for 1989, 6) BRC l policy statement and 7) ASME paper on mixed waste, j

2 The follow ..g items were recomended for consideration for the November meeting: 1) DOE's presentation on perfonnance assessment

c and perfomance allocation, 2) State of Nevada's coments on DOE Consultation Draft SCP, 3) LSS rulemaking and 4) decomissioning plan for the Pathfinder plant.

1

)

The increasing level of activity of the Comittee was noted, and it was acknowledged that additional resources, funds and personnel may 1

be required.

?.

3RD ACRS MEETING MINUTES 7 The Committee agreed on the tentative future agenda shown in Appendix !!.

B. Reports.LettersandMemoranda(0 pen)

1. ACHW Comments on Proposed Brsnch Technical Position ~Concerning i Environr. ental Monitoring for Low-Level Waste Disposal Facilities (LettertoChairmanZechdatedAugust9.1988)

The Committee recommended that an effort should be reinitiated to

! complete and issue the Branch Technical Position as well as clarify its overall purpose.

2. ACNW Comments on Proposed Connission Policy Statement on  !'

Regulatory Control Exemptions for~ Practices Whose Public Health

~~

anc Safety Impacts are Below Regulatory Concern (BRC) (Letter to Chairman Zech dated August 9. 19E8) .

The Committee recornended several revisions to the Policy Statement. I such as, exemptions should be based on an acceptable individual annual risk each proposed exemption should be justified, and the .

Policy Statement should require that all existing NRC exemptions be reviewed to ensure that they are commensurate with this approach.

C. OtherCommitteeConclusions(0 pen) i

1. ACNW Merbershi) Nomination l

On August 4. tie Committee discussed the nomination of i candidate ACNW Members for appointment by the Commission and means to expedite the process of selection. The Committee

also discussed candidates for appointment As ACNW Consultants.

1

2. Recuest for Information from DOE on Its Development of a Hvcrologic Model of the Scyannah River Plant Site  :

J

• j The DOE staff was requested and agreed to provide a tabulation of expenditures and additional detatis en developing a j hydrologic model of thE Savannah River Plant site.

i The meeting was concluded at 3:00 p.m. on August 5. 1988.  ;

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APPENDICES l

THIRD ACNW MEEi!NG MINUTES AUGUST 3-5, 1988 l

!. Attendees i

11. Future Agenda

, 111. SupplementaryReportonHDPEHICMaterials(Revision 1),

dated August 2. 1988, Chem-Nuclear Systems, Inc.

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APPENDIX !

ATTENDEES 3RD ACNW MEETING, AUGUST 3-5, 1988 AUGUST 3, 1988 J!ublicAttendees NRC Attendees Edward G. Collins, US Ecology Richard L. Woodruff, R !! i David Ebenhack, Chem-Nuclear W. C. Walker, NM55 '

Regan E. Voit. LN Technologies M. R. Knapp, NMS'!.

Mirza 1. Baig, Chem-Nuclear Systems, Inc. George Lear NMS'i R. T. Anderson, Chem Nuclear Systems, Inc.  :

Virgil R. Autry. State of S.C. BRH Michael T. Ryan, Chem-Nuclear Systems.Inc.

Francis C. Flynn, Chem-Nuclear Systems, Inc.

James D. Jeffrey, Chem Nuclear Systems, Inc.

William B. House Chem Nuclear Systems, Inc. l Leonard Toner, Chem-Nuclear Systems, Inc. i AUGUST 4, 1986*

Public Attendees NRC Attendees i

Thomas Hindman, USDOE DP-12 George Lear, HMSS Donald C. Fulmer. USDOE SR M. R. Knapp, HMSS -

W. T. Goldston, USDOE SR W. C. Walker, NMSS Gerald H. Daly USDOE DP-123 R. L. Woodruff, R !!

Jerry A. O' Leary, USDOE, DP-123,BDM Angus D. C. Kimins, UE&C/Weston 1 Melanie Ann Kelley, WJBF, Channel 6  !

Wilbert Diggs, WJBF, Channel 6 '

Mark N. Silverran USDOE SR J. W. Anderson, Perfonnance Develerment Corp.

M. J. Plodinec. DuPont SRL Dyanna Marshall USDOE/DWPF l Lewis C. Goidell, USDOE SR Kathleen Z. Wolf. USDOE SR L. M. Papouchado. DuPont, SRP G. T. Wright, DuPont, SRL M. G. O' Rear USDOE SR John A. Winters. Augusta Chronicle Robert C. Webb, US00E SR James W. Graver USD0E SR Public Attendees NRC Attendees Edward G. Collins US Ecology M. Knapp, HMSS Jim Gilpin, INENCO, Davidson, NC R.E.Trojanowski, R !!

Heyward G. Shealy, State of S.C., DHER l Woodrow M. Poplin, Engineering Design & Testing >

Gerry Motl, LN Technologies Regan E. Voit. LN Technologies Paul Denault, LN Technologies Virgil R. Autry State of S.C., BRH William B. House, Chem-Nuclear Systems Dennis Jones, LN Technologies

iG APPENDIX !!

.. FUTURE AGENDA )

l September 13-14. 1988 Low-Level Waste and Decomissioning Division (0 pen) - The Comittee will be briefed by the Director of the Low-Level Waste and  :

Decomissioning Divistorc on plans for FY 1989. i i

Regulatory Responsibility (0 pen) Estimated time: 1.5 hrs. - The Comittee will be briefed on an ASME paper on regulatory j responsibilities for mixed waste.

Low-levelWasteHandlingProcesses(0 pen)Estimatedtime: 1.5 hrs. - The j Comittee will be briefed by the NRC Staff on cement-based LLW forms.

! High Density Polyethylene HICs (0 pen / Closed) Estimated time 2 hrs. -  !

, The Comittee will be briefed by the NRC Staff on HDPE HICs. l 4

i

) BelowRegulatoryconcern(0 pen)Estimatedtime: I hr. - The Comittee l willcontinueitsreviewoftheBelowRegulatoryConcern(BRC) issue t

! with the goal of developing a position which cnuld be incorporated in an i

NRC policy statement before the International Meeting on BRC is held in  !

Washington. D.C. in October 1988.

]

j Decomissioning (0 pen) Estimated tire: 0.5 hr. - The Comittee will i discuss the "Financial Assurance Reviews" portion of the ongoing l

{ rulemaking on "General Requirements for Decomissioning Nuclear  !

)

Facilities."

i i j DOE's Dry $sent Fuel Storace Cask Study (0 pen) Estimated time: 45 '

i minutes - T1e Ccmittee will be briefed by the IMNS staff on the DOE

study on dry cask design and use.

Comittee Activities (0 pen) Estimated time: 2 hrs. - The Comittee  !

will discuss anticipated and proposed Comittee activities, future  ;

q i

meeting s;hedule, and administrative matters, as appropriate.  !

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} Neverr,ber 3-4.19M (tentative) i DOE's HLW Performance Assessment Program (0 pen) - The Comittee will be

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! briefed by the DDE 5taff on their Performance Assessment Program.

1 State of Nevada (0 pen) - The Comittee will be briefed by repre-

! sentatives from the State of Nevada on their coments on the DOE CDSCP. Responding coments will M made by NRC Staff.

High Level Waste Division (0 pen) - The tcmittee will be briefed by the

UTrector of the Division ~of High-level Waste Management on plans for FY i 1989.

I Rulemaking Topics (0 pen) - The Comittee will be briefed by NRC Staff en j rulemaking topics to clarify 10 CFR 50.

j Comittee Activities (0 pen) - The Comittee will discuss anticipated and

! proposed Comittee activities, future meeting agenda, and administrative i matters, as appropriate.

l i

t t* CHEM NUCLEAR SYSTEMS,INC.

220 storeridge Othe

• Cofwmbia, Soum Caroline N21o July 28, 1988 RA-04)5-8 Or. Michael Tokar Section Leader, Technical Branch i Division of low-l.evel Haste Hanagement

! & Decommissicaing, NHSS I U.S. Nuclear Regulatory Commis'. ion MS 5-E-4 11555 Rockville Pike Rockville, Maryland 20!S2

Dear Dr. Tckar:

Under this cover Chem-Nuclear Systems, Inc. transmitt its restense to the Silling Report as discussed,in our meeting on Hednesday, July 13, 1988.

If you have any questions or if I can be of assistance please do not hesitate to contact me.

Sincerely, ,

CHEH-HUCLEAR SYSTEMS, INC. l W V~

Hlchael T. Ryan, Ph. . C.H.P. j Executive Director '

Regulatory Affairs HTR/rhs attachment l

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1544Q APPENDIX III l

l (603) t$$o450 e Tetos. 216947 ,

I

4 :.

! $UPPLEMFHTARY REPORT ON q HOPE HIC MATERIALS l

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i PAEPARED IN RESPONSE TO i

US NRC REQllEST lj OF 7/13/88 i

I (REVISION 1) i 1

a*. - ,

j CHEM-NUCLEAR SYSTtHS, INC.

220 STONCRIO3E DRIVE

, COLUMIIA. SCUTH CAROLINA 29210 i

4

! AUGUST 2, 1988 e

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- - - -* n .- . -- --m-nnn- , , , - - , . . n------, . , ~ , , .,- - - ,w., , , , , , - - - - - - - , , - . --,g-,,

. l 1.0 Introduction & Sumary '

1.1 Introduction This supplementary report presents Chem-Nuclear Systems, Inc.

(CNSI)'s evaluation of the material properties and ' structural capability of high density polyethylene (HDPE), (cross linked) related to its application for burial of low-level radioactive waste (radwaste). Specifically, the radwaste is placed within ;

HOPE vessels known as high. integrity containers (HIC's) at various nuclear reactors and shipped with transport casks to the Barnwell, LLW facility for below ground disposal.

The purpose of this report is to address various concerns related to the suitability of this material for the proposed 1 application. In so doing, the inforr.ation should establish l that HOPE material can be designed to safely accomodate earth burial loads. These concerns were reported by Dr. Silting of Brown University in Ref.1. The points were addressed by CNSI )

at a meeting with the Nuclear Regulatory Comission (NRC) on '

7/13/88. At this meeting, CNS! was reqvested to prepare a l written response elaborating the various points presented in this meeting.

The remainder of this report covers data ano evaluations s related to HOPE HIC perforr.ance. It is presented in the '

i following sections:

! Section 2.0 HIC Burial Data ar.d Conditions at Barnwell Section 3.0 HIC Irradiation' Dose Evaluation i  !

Section 4.0 HOPE Embrittlement Evaluatien i l

Section 5.0 HDPE-HIC Buckling Analysis i

Section 6.0 HOPE HIC Creep Stress Evaluation 2-l l

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l 1.2 Background Information l L.

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.. Cross linked HOPE has been approved for burial of radwaste in KIC's at Barnwell since 1981. This material is also used for

. other non-nuclear weste burial applications, e.g. chemical l waste forms. This is due ta its excellent properties for l containment of potentially corrosive waste nattrials.

To our knowledge. HOPE is only used for radwaste disposal at the Barnwell site. $1nce burial depth at the other radwaste '

burial sites are over two times greater than at Barnwell, the structural loads on the vessel are also much higher. The NRC/Silling questions on HDpE-HIC application focus  !

specifically on the capability of this material to withstand  !

the structural loading lepesed by burial. This loading is due to burial under 20 feet of soll (a 16 psi static load). The l burial loading requirer.ents structural and duration on the HIC i are defined in Ref. 2 by $C OHEC. One of the requirement' is that the HIC must maintain its structural integrity under these burial conditions for a 3C0 year period. In this regard, the HIC's are used as disposal containtrs for dewatored ion-exchange resins discharged frcm nuclear power plants. l These resins are used in the clean-up of retetor coolant water strees. The resins contain 8 and C types of waste (as defined -

in 10CFR61) with certain long-1tved isotopes. The genesis of .

the 300 years burial design lifetime is based en 10 half Itves '

of Cs-137, (Cesium 137) which is a fission product derivative and is a significant isotopic constituent in radwaste. This is due to its comparatively long half Ilfe an$ that it frequently represents10-201, of the total curie content in 8 and C wastes shipped in H!C's. 1

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The following points are made by CNS! in the report .

1 Earnwall Amelien1103 - The HIC application and rJsulting

, l data relate specifically to its utilleation at Barnwell. '

This is not a gettis situation. The actual Barnwell data regarding the nature of HIC burial, contents,  !

radiation dose, fill level, etc. is available and can be bounded.

. MIc Radiation Dose - A study of liner attual absorbed dose shows that the integrated 300 year absorted dose is in the 106R range vs the 10IR limit. Hence. l l radiation dose has a very limited effect on HOPE l

properties.

1 HbPt tebrittlamt - Actual 14 year test data frcm  !

Phillips (the HOPE supplier) on Harler CL-100 indicate ,

that the ir.bri t tl ement (ductile-to-brittle transition)

, effect is not nearly as significant as predicted. l l

Hic Will Buck 11,e - Analytical nodeling of HIC buckling is very difficult due to the nor-linett effects of HOPE  !

,, under leading condittens and including the real world - i effects of soil-structure interaction and cartial filling I of the HIC's with a knovn material. The best verification of buckling adequacy is a vessel coepression l

test simulating actual burial conditions. CNS! has successfully performed such tests even under overicad conditions.

Wic-MBPt craen sttait Phanemana -The effect of material creep has been incorporated in HIC design. Engineering judgment wis used te establish a design stress value, For low stress levels. Marlex CL-100 exhibits a very 4

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small secondary creep strain rate. The maximum allowable stresses were derived by extrapolation of the creep data to keep the a: cumulated creep strain to a small value.

In sumary, it is NSI's contention - based on prior testing and evaluation of HDFE that this material can "be safely utilized for the actual HIC applications. Engineering design stress parameters with realistic conservatism and reasonable judgement concerning the exact nature of the burial application can and have been used to design these vessels.

2.0 Barnwell Conditions An evaluati n of a material application should realistically consider the actual service conditions, i 1gn guidelines should be sufficiently conservative to prov'de safety, but should not unduly penalize a materiti by placing restrictions and reflecting conditions that never exist in actual practice.

To place some degree of reality to the HDPE material situation, this section presents specific data on its use as a radwaste container at Barnwell.

The following points relate specifically to the burial conditions of HDPE HIC's at earnwell:

(1) Barnwell Only - At present Barnwell is the only radwaste ~~

site which burles HOPE HIC's.

(2) Barnwell Burial Hi.thods. - HIC's are buried in a 20 foot deep trench. They are covered by sand, clay, and vegative soil. The sand is scquentially compacted to minimize the possibility of earth voids or arches. The earth cap is inspected monthly for damage (e.g. evidences of subsidence, erosion, etc.).

. - - - - , , - - , , . - , , . - - - - - - . . _ _ . . - - . _ . . .- . - - - - - , - , . , --,,.c. ,,,-

k, (3) HIC Ouanti ti st / Sins - About 500 HIC's are used annually. A total of 627 HIC's were buried in Barnwell

.. in 1987. A typical (HIC is nominally 74" $ X 78" High with 1/2 - 3/4 inch thick HDPE walls.

(4) HIC Fill Rate - Barnwell site receipt criteria' require a minimum of 85% filling of the vessel with radwaste.

Economic conditions make higher fill volumes desirable.

Fill materials include standard bead resins, Ecodex and Powdex resins. Hence, some internal support of the vessel under burial conditions is provided by the fill medium. The fill media can be physically characterized.

(5) HIC Fabrication Procen - CNSI HIC's are fabricated using Marlex CL-100 resin supplied by Phillips. The 4terial is cross-linked. The fabrication process is rotational molding and CNS! HIC's are supplied by only two fabricators. Hence, reasonable consistency in

~

fabrication technique and "as-bu 't'" properties can be expected and are verified by rigid quality control 4

requirements implemented by CNSI.

(6) RLdicactive. Content - Extensive data exists on the 1

radioactive material centent in all burial containers. A l survey was made of all shipments to Barnwell in 1987 and . I special examination made of al1 HIC shipments made in ' ,

1987. Table 1 presents data on the entire 1987 isotopic inventory. The isotopic content is representative of prior year experience, Figure 1 shows the distribution of all 1987 HIC dose rates. In this regard, special examination was also made of the cases with highest centact dose (87 cases or 15% of total) to evaluate worst case situations. These summaries show that the absorbec dose of radioactivity can be established for HICs within certain upper limits.

1987 HDPE SHIPMENTS TO BARNWELL MArta4Und HOPE UNER CONTACT DOSE RA1E 400 g 350 - -

)

300 -

t i y %D-I b

i 200 -

~

En

~

8 O

y w 150 - /

e 100 *

~

. 64 50 -

l4 Vi 6

/d 5 5 VA W2 5 ,

h vb c 3 4

]- 3000 6000 10000 25000 50000 100000 >100000 MAIllRM HDPE $1NER ColfTACT DOSE RATE, mR/lR T

Figure 1 Frequency.a listribution of HIC liner contact doso. Levels l

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TABLE 1 l 1987 Barnwell Disposal Inventory l}

3 ISOTOPE Cix10 -

Gamma Energy Fraction 71/2 (YRi)

(MEV) l

1. Fe-55 86.0 2.6 0.23 .408

2. Co-60 68.9 5.3 1.17.1.33 .327

3. Mn-54 10.0 0.8 0.84 .047 l

4. Ni-63 9.1 100.1 Beta emitter .043  !

5. Co-57 7.5 0.8 0.12 .036

6. Gd-153 7.1 0.7 0.10 .034

7. Cs-137 5.0 30.1 0.67 .024

8. Y-91 5.0 O.2 1.21 .024

9. Cr-51 3.7. 0.1 0.32 .018

10. Cs-134 3.1 2.1 0.80 El Cumulativa .976 OTHER SIGNIFICANT ISOTOPES l Kr-85 10.7 0.52 .0003 9

K-40 1.26X10 1,46 <.0001 Na-22 2.6 1.28 <.0001 Eu-152 12.0 1.41 <.0001 l l

l 1

~~

M The total 1987 Barnwell isotopic inventory was 211,000 Ci '

l i

I

^ ^

.- 1 3.0 HIC Irradiation Data 3.1 General The Ref. I report is concerned with the degradation of the HDPE material due to irradiation of this material by the'. contents.

The assumption was made that All vessels are irradiated to a highly conservative design basis limit. The CNSI data indicated that the irradiation dose is much less. A

{

methodology was developed for calculating the irradiation dose l to HIC vessels based on actual loading ccnditions. The 1987 Barnwell data base (Ref. 3) of 627 HIC vessels was used. The  !

guideline for the limiting absorbed dose is 10ER for the 300 year burial period (Ref. 2). This radiation limit was established to preclude both physical degradation of the vessel polymer by irradiation ar.d to minimize the generation of internal pressure in the vessel due to radiolysis of the resin material.

The key variables for limiting high irradiation doses to the HDPE wall prior to vessel filling are:

(1) Hioh curie content (or contact dose value). This leads to high vessel contact dose rates, and hence a higher I value of absorbed doss. l i

(2) Rich Cs-137 Isoteric _

conteA1 This isotope is comparatively long lived and contributes significantly to the vessel absorbed deso over the entire 300 yest period.

(3) Hio5 co-60 isotonic content. This isotope is the highest gamma energy contributor, and is the dominant source leading to a high contact dose value.

In certain situations, tto.th a high dose rate and high Cs-137 content are present in the waste. In these cases. CNSI has required the waste generator to perform an assessment of ICPE dose rate and enforced these limits prior to shipment

.g

, - . _ _ . - - _. .-_,__m _ _ _ _ _ _ . - _ _ _ _ _ _ . _ . _ _ _ . _ _ _ _ _ , _ _ _ _ , _ _ . . _ _ - _ _ _ , _ _ , _ , _ _ - . _ _ . _ _ ~ _ . _ .

(Ref. 4). In these cases, the preliainary predictions of

.. absorbed doses were more severe than the actual dose results calculated for the loaded HIC vessel.

3.2 Results Figure 2 shoi.s conservatively calculated upper limits of absorbed dose for 95% of the HIC's shipments. Two conclusions can be drawn from these curves.

• A 300 year integrated absorbed dose of < 2X10 6R is much less than the 1X108 R limit for over 95% of the HIC liners being disposed of. An average HIC liner has a 300 5

year integrated dose in the 10 R range.

• The integrated dose absorbed by the HIC typically reaches an asymptotic limit after 40-50 years or less. The dose buildup rate is "orders of inagnitude" less than for experimental tests of HOPE samples which are irradiated in 103 -104 R fields.

An additional exanination was made to find a worst case. The isotopic breakdown of 87 HIC shipments with contact values of 25R or greater were selected. The percentages of Cs-137 and Co-60 were calculated. The results of the survey are noted below: '

Contact Reading: 25-400 R Cs-137 Content: 0-331; Average 15%

Co-60 Content: 1-65%1 Average 22%

Co-60 4 Cs-137 Content: 0-34%; Average 37%

Several of the significant cases were evaluated to estimate the 300 year integrated dose. Even in these cases the value was less than '107R. -

. v.

Total absorbed dose rate over 300 years 4 -

l s -

'c 0  :

$ V 3.5 /

3-7 .

I o 2.5 -

=

es o= 2 /

E5 ov e .-

3 1.5 -

7 e

0 0 0 1

f ;  ; -

L, O.5 ,

Y O s

}

O 40 80 '; ?O ,

160 200 240 280 O ci! CS-137 + on CO-60 n.~ w wm o 22%Co-60 15%Cs-137 ,

Figure 2 95 percentile value of 87-HIC liner absorbed dose 4

I- 3.3 Methodoloav (1) The 627 HDPE shipments were categorized by cc lact dose as shown on Figure 1. The spectrum of the vessel maximum contact doses were evaluated statistically:

l Median Value 2.5R l

Average Value 15R 95% Percentile Value 60R (2) The Barnwell isotopic values were compiled. Eight isotopes comprise over 97% of the Curie content and over 99% of the effective energy (See Table 1). Cobalt-60 is clearly the wajor contributor to dose rate.

(3) The 300 year integrated dose for any isotope was calculated by:

~ht 0

300

- Dg (l-e g )j EQ.1 khere 0 300

- 300 year integrated dose, R Og . HDPE liner wall absorbed dose, R/Hr t - 300 years x 8760 hr/yr h . .693 Tg isotope half life, years (1gns/co)

The absorbed dose rate was estimated assuming a Co-60 source in a typical (14-195) liner using the Microshield computer program. (Ref 4)

D A

Og-D e EQ.2 Where Do - outer wall conttet dose rate - 60R (95 percentile value) 1 Og - inner wall dose rate - 70R l (calculated using Micro $hield) l 1

Dg e 10R l

l l

l l

i For isotopes where the half life is S years or less:

e " o; ou.a3 fx ro.3 For multiple isotope conditions:

. l r -y' s

1-G , cc. 4 D ano~D,[7,tytf,E, xxI Examining the 87 worst case situations and assuming that only Cobalt (22 percent) and Cesium (15 percent) are present is shown below:

r, r, t, i, C8 137 0.13 0.47 0.101 of93/(1760'30.3) - 2.6 x 10 8 co.60 o.22 1.13,1.37 o.S$0

.693/(s760+s.3) - 1.ss x to.:

.101 10 .550 10

'" ' ^

,( .550 + .101 )* 2.6 x l o * *. ,(.550 + .1 of 3

• 1.49 x lo's,"I*

• O Several of the most significant cases were specifically examined from the survey of 87 shipments using the actual isotopic values and equation 4. Even in these cases. .The highest integrated dose values were all less than 1x10 7R. Hence, it is our conclucion that the effects of radiation on HDPE will be relatively small.

This situation will continue into the future based on ,

these additional factors: I

1) Radwaste casks used to ship HIC liners have insufficient shielding to handle liners with greater than 300-400R contact dose rates..

i

2) The occurrence of waste with more than 20%

Cs-137 is very rare based on the extensive CNSI-Barnwell data bass.

i l

1 l

u.

l l

l l

l 4.0 HDPE Imbrittlement The Ref. I report states that embrittlement of HDPE greatly reduces the structural capability of the material. It further states that this could occur in 30-50 years which is much less than the 300 year design life of the vessel.

The ductile-to-brittle transitions in polymers, cited by Dr.

51111ng's report is a phenomena observed mostly in the low molecular-weight HDPE at high temperatures (Ref. 6). The l physical mechanisms causing this transition, as Dr. Silling  ;

points out, are not well-understood. The main source for the l inference that Harlex CL-100 will exhibit a ductile-to-brittle l transition within the life-time of the HICs (300 years), even for low sustained stresses, is based upon the curves of Figure 1 of Ref. 1. These are referred hereinafter to as the "Graube curves".

CNSI believes that these Graube curves de not represent the material properties of Harlex CL-100 and the state of stress on the HICs accurately, Thus, they should not be used as the foundation for judging tne adequacy of Harlex CL-100 material.

He have made our judgment based upon the following ressoning.

(1) Existina Phillies Test Data

% l l

Phillips Petroleum Company, the manufacturers of Harlex '

CL-100, has performed several long term creep rupture tests, similar to the Graube tests, using 2" pipes both at room temperature and at 140' F. These continuing tests have been underway for 14 years with no indication of failure. Ref. I describes the results of some of these tests. If the data from these tests are plotted on the Graube curves (See Fig.3), it is clear that Harlex Ct.-100 exhibits markedly improved properties beyond those of the Graube curves.

GRAUBE CURVES.REPLOTTED FOR 20'C AND 60'C .

I* .

- g n '

A m ble n t .

temp.

W CL-100 m

N_

Lg '-

m

~

I v

3 ...

~. .

U N \

$ N 4o'c \

g A 1

3 2

s.s (0 I c' as'

\ 28 10 1

Time (b)

.. s

~ - - represents a probable creep-rupture behavior

. @ Phillips Petroleum test data at 20'O (under progress)

~

d Phillips Petroleum test data at 60*C (under progress)

@ Tensile rupture stress for Marlex CL-100 Figure 3 Stress to Ruoture Data of liarlex C1-100 O

e

_ - - - - , , . _ - , - _ . - . - - . - - . - - - - - - - - - . - . _ . ....r_ , , _ __ .

,' Extrapolation of these data shows that the ,

ductile-to-brittle treniitton in the material does not occur at the times indicated by the Graube curves. This is not surprising since cross-linked HDPE was developed to be suitable for high temperature applications. J Bearing in mind that the cross-linked Harlex Cl.-100 is an ultra-high molecular weight HDPE, it may be argued that )

tnis transition is unlikely to occur in the material )

under a relatively low state of stress at the 15*-20*C j (trench temperature) within 300 years.  !

(2) GrauboDataIsNotAeoiicable 1

The Qraube curves are based upon the results of an ,

internal pressure loading on circular pipe with plugged l ends. This gives rise to uniform circumferential and ,

axial stresses which are both tensile in nature. The l burial loading on the HICs results in comoressive stresses in the sidewall and tensile nembrane stresses in l the top-head. Also. the creep-rupture behavior of the l HIC sidewall in comoression is intuitively different from the tensile-creep data of the Graube curves which is based on uniform loadings. The magnitude of the HIC sidewall stress is approximately 600 psi. Even considering tensile creep, this is a small number and can be sustained by Harley CL-100 for longer than 300 years. ~

PIPE HIC T*

• 8H '

l N'

)

s

) ~

l i

f C + u.3 i

/ m

~ ..  ?

- - - . . - - . _ . - , - . . _ _ , ,, -__. ,,, _ ,,--,~_- - , . .

. _ . _ _ . - _._w__-.

Initially, at the time of buriel, the tensile cembrane stresses in the top-head of the HIC are approximately 1.000 psi. Af ter a period of time, the top-head, under the burial loading conditions deforms downwards - towards the contents where the total deformation is limited by the depth of the void space between the contenth and the top-head. The effect of creep is to increase this deformation. Hence, af ter this time period, the stresses in the top-haad will be reduced when the top-head makes contact with tV contents since most of the load is transferred to compressing the fill media, u,

e 0

5.0 HDPE Buck 11no_ Evaluation 5.1 General The Ref. I report contends that the vessel will buckle under the burial load conditions. In this regard, previous CNS!

tests and calculations refute this concern. The primary concern is the degree of conservatism in the analytical modeling and the relevancy of prior tests.

The buckling of the HICs under burial load conditions is an undesirable phenomenon. Buckling is a torn which refers to the phenomenon which occurs when the appilcation of a load beyond a critical limit results in an unstable vessel geometry. For HIC's, the onset of buckling can be specifically defined as the deformed shape of the HIC which is no longer capable of supporting an additional load over it. CNSI agrees that l buckling must be precluded in the HIC design. The point of contention is the conservatism in an analytical model. The theoretical evaluation of buckling stress of HICs is very complicated due to the nonlinear properties of the material.

The problem becomes even more complicated if soll - HIC interaction and the time variable creep behavior of Harlex

, CL-100 HOPE is to be analyzed.

5.2 Proble'ns with Ref.1 Ant.lytical Hodeling Approa:h In Ref. 5, the approach for evaluation of creep buckling stress of the HICs employed closed-form / experiments 1 results for idealized-shaped metal, not plastic, in the equations. CNSI feels that these simp 1tfled models are not realistic and hence, overly conservative. CNSI questions the following specific l areas in the analytical model:

l l

1

, n , - - - - , . - - - , , _ - - - -

- - - - , - - - - , - - - , - - - - - - - . . , - , - - , - ..-n---- - ~ - - - -

. i

.' s (1) Metal vs. Plastie Bucklina Moden 1

.=

The buckling stress formulas available in the literature j have been compiled using the test results of metal l shells. They incorporate, among other things, the mechanical imperfections and scatter of test results.

Hatal shells with dimensions comparable with typical HICs would buckle in the characteristic shape of a moderately long cylinder. The HDPE HICs, on the other hand, show a characteristic local buckling shape observed in actual HIC vessel compression tests. These buckling shapes are different from metal cylinders. These tests have been performed under very high loads (several times higher than the postulated overload) and performed by independent test laboratories on behalf of the CNSI. The differences between theoretical and experimental vessel buckling shape shows the limitations of the closed-Nrm / experimental test formula?' and their applicability to the HOPE HICs.

i l

(2) Inameli cable _Us e.gQcant Hedul_n The use of the secant modulus ir the forculas of critical

, , stress for creep-buckling was derived by Chern for the instability of a tube in a tubular heat exchanger which was operating at high temperatures. Its application to the evaluation of the critical buckling stress for HOPE HICs is not considered valid and is questioned by the CNSI on the following grounds.

(a) The Ref. I calculations method employs an equation of state approach, i.e. it is assumed that the response of the material depends explicitly on the l present state. This approach has even been questioned, for metals. It has been argued that the

~

l-only valid representation of creep is one that incorporates the memory of past events. This approach is suspect when used for viscoelastic materials, whose response is highly path dependent under the large strains sustained.

(b) The Ref. 1 calculational method embodies the assumption that the dependence on the material properties and geometric properties can be separated. This assumption is not valid for situations with large deflections where geometric changes give rise to stress stiffening.

(c) The Ref. 1 calculational method empicys a critical effective strain approach where there is no stress redistribution. Ref. 8 states that there is rt'Jistribution of stress from the initial state to a final state whenever the load is constant and the problem is statically indetermine.te. Therefore, the HOPE HIC's under the burial loading do redistr?bute stresses, violating this asst;mption.

(d) The calculationa' method in Ref. I assumes that

"* compression and tensile properties for H0pE are identical. Ref. 6 states that this is not always the case and ons should be careful to verify it for the material under consideration. The compression k h h k j "~ C,CEPN / e a me N

)lM4

creep curve is the tirror 1r. age of the tension creep curve. This certainly 18 the case for HDPE, where compression and tensile prope ties are expected to be different since the materihl has a high Poisson's ratio (0.45). The expected difference is due to cold flow of the material, since the cross section greatly increases under compressive loading. The  ;

creep behavior in comp'ression h clearly markedly I different in compression than in tension.

(3) Effect of Soil Structure Interaction Hust be Considered The e,xperimentally obtained critical buckling stress with a constant pressure loading fer a relatively flexible structure (e.g. a horizontally buried cylindrical shell, hemispherical-head caps, etc.) is conservative by a factor of three to four. This is compared to the case I when soil-structure interactions are taken into account (see Bulson, Ref. 9, pages 160-167). The Brookhaven National Laboratory Report (BNL) (Ref. 10) has conservatively derived a formula to account for the soll structure interaction effect on the HOPE HIC buckling.

When values of the parameters corresponding to the Barnwell soil conditions are substituted into the BNL formula, a ratio of approximately 3 is obtained between the critical buckling stress (when comparing the effect ' l of the soil-structure interaction to a case where there is no soil structure interaction).

J (4) HICt Are Leaded with Haterial Per the Barnwell site license, the liners must be a minimum of 85% filled. There are only three waste material resin forms that are used to fill the HICs which are (a) bea'd resin, (b) Powdex resin and (c) Ecodex. The 85% volume Ilmit ensures that the entire cylindrical

0

. portion of the HICs along with a portion of the torospherical top will be filled with the waste form.

.... The cylindrical portion of the HIC vessel wall will be backed by the waste. form from the inside. However, the torospherical head will only be partially backed by the waste and may be subject to a snap-back deformation.

This snap-back deformation occurs when a part of the s.ony.n "up" shape changes to a concave "up" shape due to soil loading conditions.

, l

..~...., 1 n..f . c.< . .. . .r 1 wy.

I i This configuration will cause a tensile loading in tha head. However, this is not considered to be an unstable  ;

configuration (per the buckling definition). In this I configuration, the cencave up (or deformed) position of l the HIC will behave like a shallow dished-head. Such a )

shape is known to have small rigidity against transverss load. The soil volume directly above it will have an "active" soll arching. Therefore, the soil pressure on this position of the head will be reduced.

The Ref I treatment of the soil "arching" phenomena is not accurate. In rany cases, soil arching actually '-

reduces the earth loading on the HIC top-head. McNulty examined the effect of soil arching (Ref. 11), using a circular trap door mounted flush with the bottom of a circular soil container to evaluate the effect of door flexibility on the soil archin0 ratio. His results are reproduced in Figure 4. It can be seen that for active soil arching 1.e. trapdoor deficction downwards, the soil pressure is reduced to an extremely small value. Ref. 9 describes Terraght's experiments with a long rectangular  ;

trap door and comes to a similar conclusion. (See Figure l

5) Although these experiments are not exact duplicites l

l l

of the HIC loading conditions, they are still relevant.

These experiments claarly indicate that for a flexible horizontal member buried under a soil column, the pressure transverse would typically be an order of magnitude smaller than the pressure corresponding to the l total weight of the soil column above it. l l

5.3 Potsible Methods of Evaluatine Buckline Potential l

l CNSI's rei. son for pointing out the var 4bles involved and the limitations of the available theoretical / experimental data is <

to highlight the inability of the state-of-the-art in analysis to simply model the behavior of the HDFE HICs. Simplistic analytic models with overly conservative boundary conditions will certainly lead to high vessel stresses and conclusions I which we feel are overly conservativs which don't reflect the  !

actual physical situation. The modeling situation is very I complicated when consideration i s given that the HIC's are filled with waste and surrounded by compacted soll. The l

available method that will best predict this behavior is a i detailed nonlinear finite element analysis using a combined '

model of the HIC, the surrounding soil and the waste. However, this method would require characterizing and bounding the waste properties, as pointed cut in Ref.1. This character 12ation is

~' possible, the mechanical properties of the waste that are required to perform this type of analysis are the elastic modulus E, and the Foisson's ratio, v. These properties can be established by testing the three known waste forms, described earlier, by suitable methods. Confined modulus, E,

g and bulk modulus E , can be measured and the test data 3

can be used to obtain the elastic modulus and the Poisson's ,

ratio using the following two equations, l

- II~")

E*

(1 + v)(1 - 2v) 1

~

(1-2v) i

- - - - - _ - . ,__ - - . , _ , .,,--,-_.m _ _ _ , _ _ _ . , - - . . . _ . - _ . . _ . _ _ , _ _ _ _ . _ . . -

. . i o

iss 44t' l y l j mvsrQg*r*e,m a u.

L'(' + a

>b4 -

Arching ratlo, p /A, N g/8

. S'D N

%(2 ,

30 2'g

.............f..% ..*

. . . . g. . ... ,,,,,,,%  %. . SO

a.y.

k' ,.s ee#' .s . , ,.. '

sO 0',

fk q

.. ,3 t- . i \ t  %.........,..-,-- .s 5 -4 3 -2 1 0' 1 2 3 4 (8/B) x 1000 Figure 2.4 McNulty*: expriments.  !

= .

Figure _4 Effect of Traodoor Flexibility on Soil Archine (Reproduced.fromJ if. 9) f

., , . , - - - - . - - - , - - , - , - - - e . , _ , , , - - - , - - - - , - - ~ ,, - - - . ,

,m -

---, - - - -- --- --,n n , -

• l

.'. i Surloce-- ---

4 ~

Compocied sond, 4=44' 3 ' Distribution of

, , verticol pressuce. l

' 1/b  ;. .-

-25.'

2 -

I l

N

, o orching 1 -

\ Arching

. 1 1

0 I' i iiii i i ' o l

. Trop door, 02 04 06 08 10 i v vh a .. Figure 2.1 Terzaght's trapdoor experiments (note: m'easured upwards from trapdoor).

b = trap-dcor wld.th H = helght of the over burden

-',0, a soll stress at z c,s - soll stress with no arching (hydrostatic stress) -

Fiaure 5 j l

Terzachi's Trapdoor Experinent Resu1 Q ,

)

(ReDroduced fren Ref.9) 1

- ts .

. . . l

C 1

However the finite ele:ent model using this approach will 1t111 be debatable due to the tolerances in the assumptions and boundary conditions involved. Therefore, CN3! feels that  !

testing under simulated Barnwell cenditions seems to present )

the best means of verifying the buckling behavior.

CNSI has tested prototype HICs under the simulated Barnwell burial conditions (see Ref.12). Tht HICs were filled and the compression loading was applied through a soil-like medium.

This test was continued over a period of more than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and the deformation was monitored. No buckling failure was observed in the container. Admittedly, this test shows the short-term behavio of the HIC. It does not completely evaluate the effect of creep buckling. However, BNL, using a l soil-structure interaction model including the viscoelastic properties of the HDPE (Ref.10) has shewn that the initial buckling load is smaller than the creep buckling load. This means that if the buckling of the HIC does not occur during the simulated testing time, it will not occur due to the material creep. The creep behavior of the HOPE could be incorporated into a simulated buckling test. The duration of the testing would be increased to a time over which the decrease in the creep modulus of the HDPE takes place for the anticipated amount of stress. Most polymers show the onset of the

, secondary-creep at about 500 hours0.00579 days <br />0.139 hours <br />8.267196e-4 weeks <br />1.9025e-4 months <br /> (see for exaq:le Ref.6, page s 410) after which the change in creep modulus is rather insignificant. Therefore, compression ~ testing cf the H:Cs to this perind, f.e., 500 hours0.00579 days <br />0.139 hours <br />8.267196e-4 weeks <br />1.9025e-4 months <br /> (21 days) will be sufficient to test for creep buckling. In such a test the period of  !

performance and buckling acceptance criterion must be agreed upon prior to testing. f

P. f.0 HDPE-MIC Creen Stress Evaluation In Ref. 1, the contention is made that the analysis did not consider creep phenomenon. The allegation by Dr. Silling that the industry ignored mat 3 rial creep is unfounded. The creep-rupture behavior of the Harlex CL-100 material has been incereerated into the design of the HICs by establishing the creep-rupture stress for the 300-year life of the HICs.

The CNSI design approach has been to limit the maximum stress in the HIC as selected design stress vs.lue based on examination of creep stress curves in Ref. (14). Engineering judgement has been used in establishing the stress values and did consider creep. Thi's approach is not uncommon. For eranple, the ASHE Code Section !!! allows a linear analysis to incorporate effects of nonlinearities (such as plasticity) in design by analysis of nuclear power plart components.

The use of tensile creep-rupt ure date. to limit the compressive sidewall stress is conservttive. The sidewall compressive stress is approximately 600 psi. Under compression loading, the HIC sidewall cross-section increases, and the material does not exhibit the same creep behavior as it does in tension. The top-head loading is both conp'essive and tensile. The top-head of the HIC underloading unde"goes a snap-back deformation to a

-- concave-down configuration. (n this ccnfiguraticn, the loading ,

on the top-head actually goes down due to active soil arching of the column of soil above it. (See Section 5.0 for more details of this phenomenon.)

Therefore, the stresses calculated in the top-head, without considering the effect of tie soil-arching, is conservative.

CNSI's evaluation of the stresses in the tcp-head region showed a maximum average stress to bt less than 1,100 psi (See Ref.13).

( .. .

l

'o 1 The basis of establishing the threshold of acceptable stress in j

.. the HICs was the consideration that the secondary creep rate I

~

for this stress level ought to be small. The creep strain behavior of Harlex CL-100 is different from other HOPE homopolymers and copolymers, as noted by Dr. $1111ng (see Table l 2 of Ref.5). The primary creep rate of Marlex CL-100.is higher than the other types of HOPE, but the onset of tertiary creep l in CL-100 is much delayed (see Ref.14). The creep strain data '

of Ref.14 shows that the strain rate is essentially zero for a stress level of 500 psi. It is still small up to a stress l 1evel of 1400 psi. Extrapolation of this data to a 300-year container bur.lal lifetime results in a small accumulated creep strain. Hence, CNSI established a stress level of 1400 psi.

BNL, using the results of tests on Hartex CL-100, has i established a levt1 of 1.100 psi (see Ref.10), which is not significantly different from the CNSI established limits.

Irrespective of these differences, both parties agree that a limit on design stress can be established.

The question of limiting the exact amount of creep deflection is i naterial when considering the actual HIC burial conditions. As described uri t er, the HICs sidewalls have compressive stresses of about 600 psi. Stresses of this magnitude would not result in the sidewall compressive strain l

larger than 3 to 61 over the 300 years design life. The top-head deforms downwards - towards the contents - under the '

burial loading condittois. Thus, the total deflection in the

, rost pessimistic case is limited to the depth of the void space between the content and the top-head. Since the containers are filled to a minimum of 851 volume, this deflection is still reasonably small.

l

[  :

i

$' Referene's e

. (1) "Review of the Structural Design of High Integrity Containers" by S.A. l Silling. Report submitted to NRC, May 10, 1988.

(2) "Guide for High Integrity Container Topical Report Application" South !

Carolina Department of Health and Environmental Control, July,1985.

l (3) CNSI Data Bank of 1988 Shipments to Bart.well, S.C. .

)

(4) GPU Nuclear Corporation Comunication to CNSI, No. 4230-88-078.HTC,  !

Dated March 14, 1988.

]

(5) Microshield Version 3.1, User's Manual. Grove Engineering, Inc., !

Aprl) 4,1988.

(6) Hodern Plastics Encyclopedia, 1985-1986, a McGraw Hill Publication.

(7) Personal Communication from R.L. Rees (Phillips 66 Company) to H. Batg (ChS!), July 12,,1988.

.. )

(8) Harry Krams, Crete Analysis, a John Hiley Publication,1980.

(9) P.S. Bulson, Buried Structuret, a Chapman and Hall Pubitcation, 1985.

(10) "Review of the High Integrity Cask Structural Evaluation Program I (HICSEP), BNL Technical Report, April 6,1987.

(11) McNulty, J.H., "An Experimental Study of Arching of Sand". U.S. Waterway Experimentation Station, Technical Report, 1-674, 1965.

(12) "Supplement to the EnviroSAFE Polyethylene High Ir.tegri ty Contairer Evaluation Report", Chem-Nu: lear Systems, Inc. Repert, September 30, 1982.

(13) "Evaluation of Stress Loadings of CNSI HOPE HICs", Report Submitted by CNSI to NRC, January 29, 1938.

(14) Phillips Chemical Company Technical Hemorandum on Harlex TSH-243, July 1975. Resinsi l

J