ML20195G415
| ML20195G415 | |
| Person / Time | |
|---|---|
| Issue date: | 10/15/1987 |
| From: | Tokar M NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Chando J, Ebenhack D, Roy B CHEM-NUCLEAR SYSTEMS, INC., HITTMAN CORP., TFC NUCLEAR ASSOCIATES, INC. |
| Shared Package | |
| ML20151C617 | List:
|
| References | |
| FOIA-88-470 NUDOCS 8811230376 | |
| Download: ML20195G415 (6) | |
Text
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001 lo oct o
, John Chando, Jr., President TFC Nuclear /ssociates, Inc.
425 Bridgeboro Road Herrestown, NJ 08057
Dear Mr. Chando:
As a result of concerns regarding the long-term stabilitj of High Density Polyethylene (HDPE) High Integrity Containers (HICs), the Nuclear Regulatory Comission (NRC) contracted Brookhaven National Laboratory (BNL) to (1) develop criteria for HDPE HIC structural stability (2) analyze existing data on the Creep of pol [ ethylene, and (3) develop a computer model to use in evaluating the structura ctability of these HICs. A dreft methodology report has been written that devribes the development of the BNL model and recomends proposed design review criteria for HOPE HICs in the form of maximum allowable values for membrene stresses, creep, and buckling stress. The criteria recomended in the report are being used to aid the NRC staff in formulating the NRC's acceptance criteria for HDPE HICs. These acceptance criteria will also be included in the NRC's Regulatory Guide on Waste Form, which is under deselopment.
The BNL computer model der mes the membrane, buckling and creep stresses for HIC geometries through a finite element analysis for time periods up to 300 years. The HICs are modeled as axisymmetric shells of revolution, corresponding to the actual design configurations. Polyethylene is modeled as a viscoelastic material, a N membrane, creep, and buckling stresses are calculated for the various loads and load combinations acting nn the HICs during their service life. The model compares these stresses with the recomended allowable stress values that are developed in the methodology report, and output from the computer modeling lists the finite elements where allowable stress values are exceeded.
The maximum allowable stress values developed in the BNL model methodology report are determined such that an HOPE HIC designed to specifications that will prevent the H!C from experiencing the maximum stress values 11 meet the requirements of NRC's Technical Position Paper en Waste Fom (M- 1983). The maximum allowable menbrane stress and bending plus membiane st .a reported in the methodology report are 1400 psi and 1876 psi, respectively. The maximum allowable buckling stress is determined for each MC individually by the expressions that are explained in the appropriate sections of t a methodology report. The maximum allowable creep stress is listed in the eport as 765 psi.
However, af ter additional discussions with BNL regarding the conservatism inherent in the proposed 765 psi value for maximum allowable creep stress, and taking into consideration new data generated by BNL, the NRC has established that 1100 psi can serve as the maximum allowable creep stress value considered by the NRC in qualifying HDPE HICs.
The BNL model has been run on several actual HDPE HIC designs using inforraation from Topical Reports submitted to the NRC for review. Results of the computer modeling analyses indicate that there may be a potential for large polyethylene contair.ers to experience excessive membrane stresses and to exceed the proposed maximum allowable buckling stress. The BNL model also suggests that HOPE HICs could potentially exceed the proposed maximum allowable creep stress. As a 8811330576 001115 '
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John Chando, Jr. 2 result of the work just described, it is the NRC's position that HDPE HICs should be designed so that they do not experience excessive membr6ne stresses, buckling, or tertiary creep.
Therefore, to aid in expediting our review of your HDPE HIC Topical Report, we request that you submit complete information that demonstrates that your HDPE HIC design will ensure long-tem structural stability as required by 10 CFR Part 61 and in a manner that is consistent with the BNL/NRC findings. This can be accomplished by demonstrating that either by (1) modification to your current designs, (2) your own analysis, and/or (3) administrative procedures, you can show that the HIC acceptance criteria will be met. The requM'ed infomation must be submitted to the NRC by January 31, 1988. Failure to submit complete information by this date would leave the NRC without the necessary bases to confirm approval or disapproval of your HOPE HIC Topical Report, and, therefore, would result in the discontinuance of the NRC review of your Topical Report.
In order to continue the expedited review of your Topical Report, the NRC staff will complete an evaluation of your submittal by April 30, 1988.
Enclosed is a copy of the draf t BNL methodology report, entitled, "Review of the High Integrity Lask Structural Evaluation Program (HICSEP)," dated April 6, 1987. Also enclosed is a copy of the BNL computer model HICSEP, and the input and output from a sample problem used to assist in implementing the r.mdel on the NRC computer..
If you require any further infomation regarding thic letter, the BNL methodology, the structural analysis model, or the NRC's position regarding High Density Polyethylene High Integrity Containers, please phone me at (301) 427-4748. ,
Sincerely, Michael Tokar, Section Leader Technical Branch Division of low-level Maste Management and Decorraissioning, NMSS
Enclosures:
- 1. Draft BNL Report t
- 2. Computer Listings
! DISTRIBUTION: (w/o encl.)
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l OCT 151981 l
, David Ebenhack, Vice President j Regulatory Affairs '
Chem-Nuclear Systems, Inc.
220 Stoner:dge Drive Columbia, SC 29210
Dear Mr. Ebenhack:
As a result of concerns regarding the long-term stability of High Density Polyethylene (HDPE) High Integrity Containers (HICs), the Nuclear Regulatory Comission (NR~) contracted Brookhaven National Laboratory (BNL) to (1) develop criteria for HDPE HIC structural stability, (2) analyze existing data on the creep of polyethylene, and (3) develop a compute ~ nodel to use in evalu.. ng the structural stability of these HICs. A draf t methodology report has been written that describes the development of the BNL model and recomends proposed design review criteria for HDPE HICs in the form uf maximum allowa. le values for membrane stresses, creep, and buckling stress. The criter'a recommended in the report are being used to aid the NRC staff in formulating the NRC's acceptance criteria for HDPE HICs. These accaptance criteria will also be included in the NRC's Regulatory Guide on Waste Form, which is under development.
The BNL computer model determines the membrane, buckling and creep stresses for HIC geometries through a finite element analysis for time periods up to 300 years. The HICs are medeled as axisymmetric shells of revolution, corresponding to the actual design configurations. Polyethylene is modeled as a viscoelastic material, and membrane, creep, and buckling stresses are calculated for the various loads and load combinations acting on the HICs during their service life. The model compares these stresses with the recomended allowable stress values that are developed in the methodology report,' and output from the computer modeling lists the finite elements where allowable stress values are exceeded.
The maximum allowable stress values developed in the BNL model methodology report are determined suct that an HDPE HIC designed to specifications that will prevent the HIC from experiencing the maximum stress values will meet the requirenents of NRC's Technical Position Paper on Waste Fonn (May,1983). The maximum allowable membrane stress and bending plus membrane stress reported in the methodology report are 1400 psi and 1876 psi, respectively. The maximum allowable buckling stress is determined for each HIC individually by the expressions that are explained in the appropriate sections of the methodology report. The maximum allowable creep stress is listed in the report as 765 psi.
However, after additional discussions with BNL regarding the conservatism inherent in the proposed 765 psi value for maximum alicwable creep stress, and taking into consideration new daca generated by BNL, the NRC has established that 1100 psi can serve as the maximum allowable creep stress value considered by the NRC in qualifying HDPE HICs.
The BNL model has been run on several actual HDPE HIC designs using infonnation from Topical Reports submitted to the NRC for review. Results of the computer modeling analyses indicate that there may be a potential for large polyethylene containers to experience excessive membrane stresses and to exceed the proposed maximum allo m ie buckling stress. The BNL model also suggests that HDPE HICs could potentially exceef the proposed maximum allowable creep stress. As a
. l David Ebenhack 2 result of the work just described, it is the NRC's position that HDPE HICs '
should be designed so that they do not experience excessive membrane stresses, buckling, or tertiary creep.
Therefore, to aid in expediting our review of your HOPE HIC Topical Report, we request that you submit complete information that demonstrates that your HDPE HIC design will ensure long-term structural stability as required by 10 CFR Part 61 and in a manner that is consistent with the SNL/NRC findings. This can be accomplished by demonstrating that either by (1) modification to your current designs, (2) your own analysis, and/or (3) administrative procedures, you can show that the HIC acceptance criteria will be met.. The requested infomation must be submitted to the NRC by January 31, 1988. Failure to submit complete information by this date would leave the NRC without the necessary bases to confirm approval or disapproval of your HDPE HIC Topical Report, and, therefore, wculd result in the discontinuance of the NRC review of your Topical Report.
In order to continue the expedited review of your Topical Report, the Nhc staff will complete an evaluation of your submittal by April 30, 1988.
Enclosed is a copy of the draf t BNL methodology report, entitled, "Review of the High Integrity Cask St.uctural Evaluation Program (HICSEP)," dated April 6, 1987. Also enclosed is a copy of the BNL computer model HICSEP, and the input and output from a sample problem used to assist in implementing the model on the NRC computer.
If you require any further information regarding this letter, the BNL methodology, the structural analysis model, or the NRC's position regarding High Density Polyethylene High Integrity Cor. tainers, please phone me at (301) 427 4748. .
Sincerely, Michael Tokar, Section Leader Technical Branch Division of Low. Level Waste Management and Decommissioning, NHSS
Enclosures:
- 1. Draft BNL Report
- 2. Computer Listings ,
DISTRIBU'!ON: (w/o encl.)
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OFFICIAL RECORD COPY
,' OCT 15 W
, Bryan A. Roy, Manager Design & Process Engineering Radiological Services Division Hittman Nuclear 1256 N. Church Street Morrestown, NJ 08057
Dear Mr. Roy:
As a result of concerns regarding the long-term stability of High Density Po'lyethylene (HDPE) Hi 5 h Integrity Containers (HICs), the Nuclear Regulatory Commission (NRC) contracted Brookhaven National Laboratory (BNL) to (1) develop criteria for HDPE HIC structural stability, (2) analyze existing data on the creep of polyethylene, and (3) develop a computer model to use in evaluating the structural stability of these HICs. A draf t r.ethodology report has been written that describes the development of the BNL model and recomends proposed design review criteria for HDPE HICs in the form of maximum allewable values for membrane stresses, creep, and buc' ding stress. The criteria recommended in the report are being used to aid the NRC staff in formulating the NRC's acceptance criteria for HDPE HICs. These acceptance criteria will also be included in the NRC's Regulatory Guide on Waste Fom, which is under development.
The BNL computer model detemines the membrane, buckling and creep stresses for HIC geometries through a finite element analysis for time periods _up to 300 years. The HICs are modeled as axisymetric shells of revolution, corresponding to the actual design configurations. Polyethylene is modeleo as a viscoelastic material, and membrane, creep, and buckling stresses are calculated for the various loads and load combinations acting on the HICs during their service life. The model compares these stresses with the recomended allowable stress values that are developed in the methodology report, and output from the computer modeling lists the finite elements where allowable stress values are exceeded.
The maximum allowable stress values developed in the BNL model methodology report are detemined such that an HDPE HIC designed to specifications that will prevent the HIC from experiencing the maximum stress values will meet the requirements of NRC's Technical Position Paper on Waste Fom (May,1983). The maximum allowable membrane stress and bending plus membrane stress reported in the methodology report are 1400 psi and 1876 psi, respectively. The maximum allowable buckling stress is detemined for each HIC individus11y by the expNssions that are explained in the appropriate sections ( ~ the methodology report. The maximum allowable creep stress is listed in the report as 765 psi.
However, after additional discussions with BNL regarding the conservatism inhecent in the proposed 765 psi value for maximum allowable creep stress, and taking into consideration new data generated by BNL, the NRC has established that 1100 psi can serve as the maximum allowable creep stress value considered by the NRC in qualifying HDPE HICs.
The BNL model has been run on several actual HOPE HIC designs using infomation from Topical Reports submitted to the NRC for review, Results of the computer modeling analyses indicate that there may be a potential for large polyethylene containers to experience excessive membrane stresses a.i to exceed the proposed maximum allowable buckling stress. The BNL model also scggests that HDPE HICs could potential.ly exceed the proposed maximum allowable creep stress. As a
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OCT 151987 Bryan A. Roy 2 e
result of the work just described, it is the NRC's position that HDPE HICs ~
should be designed so that they do not experience excessive membrane stresses, buckling, or tertiary creep.
Therefore, to aid in expediting our review of your HDPE HIC Topical Report, we request that you submit complete information that demonstrates that your HDPE HIC design will ensure long-term structural stability as required by 10 CFR Part 61 and in a manner that is consistent with the BNL/NRC findings. This can be accomp(lished designs, 2) your own by analysis, demonstratingand/orthat (3) either by (1) modification adtiaistrative procedures, to your you cancurrent show that the HIC acceptance criteria will be met. The requested information must be submitted to the NRC by January 31, 1988. Failure to submit complete information by this date would leave the NRC without the necessary bases to confirm approval or disapproval of your tiDPE HIC Topical Report, and, therefore, would result in the discontinuance of the NRC review of your Topical Report.
In order to continue the expedited review of your Topical Report, the NRC staff will complete an evaluation of your submittal by April 30, 1988.
Enclosed is a copy of the draf t BNL methodology report, entitled, "Review of the High Integrity Cask Structural Evaluation Program (HICSEP)," dated April 6, 1987. Also enclosed is a copy of the BNL computer model HICSEP, and the input and output from a sample problem used to assist in implementing the model on the NRC computer.
If you require any further infomation regarding this letter, the BNL methodology, the structural analysis model, or the NRC's position regarding Hi Polyethylene High li.tegrity Containers, please phone me at (301)427 gh4748.
Density
, Sincerely, Michael Tokar, Section leader Technical Branch Division of Low. Level Waste Management and Decomissioning, HMSS
Enclosures:
1, Draft BNL Report
- 2. Computer Listir.gs DISTRIBUTION: N/o encl . )
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