ML20062C502

Forwards Summary of 900823 Meeting W/Bondico Re Structural Stability of fiberglass-reinforced Plastic Matl Used on Bondico Proposed HIC-7 High Integrity Container

ML20062C502
Person / Time
Issue date:	09/14/1990
From:	Wick E NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS)
To:	Surmeier J NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS)
Shared Package
ML20062C498	List: ML20062C493 ML20062C499 ML20062C502
References
REF-WM-94 NUDOCS 9010310305
Download: ML20062C502 (21)

Text

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UNITED STATES

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SEP 141930 1

i MEMORANDUM FOR:

John J. Surmeier, Chief l

Technical Branch 1

Division of Low-Level Waste Management and Decomissioning, NMSS THRU:

'iichael Tokar, Section Leader A

Engineering Section 08 '^

Technical Branch f

p.70s.M-Division of Low-Level Waste Management and Decommissioning, NMSS FROM:

Everett Wick Engineering Section Technical Branch Division of Low-Level Waste Management and Decomissioning, NMSS

SUMMARY

OF AUGUST 23, 1990 MEETING BETWEEN NRC, BONDICO, AND SAIC The subject meeting sumary is %1osed.

This'sumary highlights the NRC/SAIC concerns regarding the structural stability of~the l

fiberglass-reinforced plastic material used on Bondico's proposed HIC-7 high integrity container for disposal of low-level radioactive waste (Docket Number E-94).

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Everett Wick Engineering Section Technical Branch Division of Low-Level Waste Management and Decommissioning, NMSS

Attachment:

Meeting Sumary cc: Attendees w/ attachment l

9010310305 901027 PDR WASTE WM-94 PDC

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MEETING

SUMMARY

l DATE:

August 23, 1990 l

TIME:

10:00 a.m. to 12:00 noon PLACE:

OWFN, Room 10813 i

PURPOSE:

TO DISCUSS NRC'S REVIEW 0F THE STRUCTURAL STABILITY OF BONDICO'S HIC-7 FIBERGLASS-REINFORCED PLASTIC HIGH-INTEGRITY CONTAINER (DOCKET NUMBER WM-94)

PARTICIPANTS:

NRC BONDICO NUCLEAR Jolin Greeves HMSS/LLWM Homer Lowenberg Michael Tokar NMSS/LLTB Banad Jagannath NMSS/LLTB SAIC Robert Shewmaker NMSS/LLTB Uim Hammelman-Everett Wick NMSS/LLTB John Stokely Joe Price-

SUMMARY

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l 1.

SAIC presented a summary of its review of the structural stability of the fiberglass-reinforced plastic (FRP) HIC. This review concentrated on the durability of the physical properties of the FRP.

A handout of the presentation is attached.

2.

The conclusions of the review are that water absorption effects are potential FRP degradation mechanisms which should be evaluated for long-term applications.

These potential degradation mechanisms are (a) hydroloysis of ester linkages of the polymer matrix and (b) debonding of the polymer matrix and reinforcing glass fiber.

I 3.

In view of the above conclusions, the available data base does not support a finding that a FRP HIC will retain structural' stability for 300 years.

4 Hydrolytic degradation of ester linkages has been observed experimentally.

Thus, NRC asked Bondico during the review to (a) present evidence that this mechanism will not occur in the proposed FRP and (b) present evidence to support the projection of a 300-year service life.

5.

Water diffusing through FRP would contribute to development of swelling stresses in the FRP and osmotic pressures in the vicinity of the glass fibers.

During the review, Bondico was requested to demonstrate that any reduction in strength (caused by these phenomena during the 300-year.

service life) would not decrease material properties below values required in-the design.

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6.

Bondico's respon:es to the NRC.coments raised in items 4' and 5 are sumarized below.

I a.

The two questions (potential failure mechanisms) are judged to be-interrelated and are addressed in a combined manner.

b.

Data on thermoplastic resins are not relevant to behavior of thermosetting plastics.

c.

Material properties, e.g., water uptake and tensile strength, are significantly different between the FRP material used in the hot-water tests and the FRP material to be used in the HICs.

j d.

30 years of data, under more stringent conditions, indicate that the.

l FRP has little or no tendency to suffer from hydrolytic degradation' industrial experience (Owens-Corning) indicates no problems in this area.

i e.

Imersion in laboratory water is irrelevant to exposure in the l

natural unsaturated zone environment; differences in water saturation, water chemistry, and temperature support this premise.

f.

Extrapolation of data (4 points) collected over an exposure period:

of 6 years to an exposure period of 300 years indicates' acceptable strength retention.

7.

NRC/SAIC's evaluation of Bondico's responses are sumarized below, a.

There is no direct evidence or analysis that the two degradation 1

mechanisms do not occur in the HIC FRP over long time frames._

j b.

Without a mechanistic basis, extrapolation of short-term data will not provide a supportable estimate of long-term properties.

I c.

Modification of test conditions would not change the conclusions a

that the~ degradation mechanisms are credible and need to be l

evaluated.

8.

SAIC agreed to perform the followiny actions and to document them in-its-draft sumary report.

1 a.-

Update the status of the research on water absorption that is'being performed by Ford Motor Company.

This would be done by telephoning l.

the authors of the report, which. has been referenced by NRC/SAIC and enclosed in NRC's formal comments to Bondico, b.

Determine whether it is possible from the standpoint of thermodynamics for the potential failure mechanisms to occur at' the soil temperature at the disposal site, i.e., 15'C.

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3 c.

Discuss whether it is more likely that the degradation observed in the polymer af ter immersion in 98'C water was caused by exposure to-the higher temperature rather than exposure to the water.

This would be done through discussions with a polymer chemist.

' hmn/d Nk Everett Wick-Technical Branch Division of Low-Level Waste Management and Deconnissioning

Attachment:

Handout of presentation by SAIC (Dr. Joseph Price)

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INTRODUCTION i

BACKGROUND a

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Project Review Topical Report for a Fiberglass Reinforced Plastic High Integrity Container i

and-evaluate HIC material behavior against regulatory performance requirements 1

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INTRODUCTION 1

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e REVIEW CRITERIA i

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Generak 10 CFR 61 t

Branch Technical Position on Waste Form l

l Specidic-Maintain structural integri'y for 300 years i

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Corrosion tests to confirm material

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suitability to meet design lifetime goal 1

l Radiation stability; no significan' changes in material properties to 100 million rads l

Test against biodeterioration i

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GETHODOLOGY ASW DATA REVIEW l

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l MAJOR STEPS s

I Characterize material 4

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Identify potential degradation mechanisms i

l Identify availahia data l

Assess data and determine relevance of data to j

projedia7 of HIC material properties over long time j

l frames (i.e.,300 years) 1 1

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BAETHODOLOGY AND DATA REVIEW

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CHARACTERIZE MATERIAL i

i Applicant information:

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Matrix material-Isophthalic resin produced by condensation reaction of maleic j

anhydride, isophthalic acid, diethylene glycol and propylene i

glycol, cross-linked with styrene j

j Reinforcing fibers --

E-glass l

Literature diagram-Matrix material _

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II. 00ETHODOLOGY AND DATA REVIEW l

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POTENTIAL DEGRADATION MECHANISMS Actinic degradation I

Biodeterioration l

i Thermal oxidation l

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Radiation degradation j

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t Water absorption effects i.

hydrolysis of ester linkages in polymer matrix i

polymer / glass debonding due to osmotic effects i

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l N. RAETHODOLOGY ASW DATA REVEW

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AVAILABLE DATA Applicant Data (in-situ conditions)

Water uptake;seven days exposure Flexural strength; seven days exposure, eight chemica!s t

i Manufacturer Data (in-situ conditions) i Flexural strength; unchanged after 30 years burial i

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METHODOLOGY AND DATA REVIEW l

h AVAILABLE DATA (continued) i i

f Literature Data (accelerated conditions) f i

i Polymer matrix hydrolysis j

Related polyester (polyarylate), non-reinforced, not i

j cross-linked t

Glass / polymer debonding j

Similiar material, fabrication technique i

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Unspecified Fragmentary data on loss of flexural strength of 1

l isophthalic resin FRP following immersion in water at 4

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0 72 F and 210 F i

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NEED TO PRESERVE THE NECHANISM o

USE REPRESENTATIVE CONDITIONS 1

SANE CONPOUWS 4

SAME CNENICAL POTDff!AL OF AMBIDft NATER SANE CONCENTRATION OF SOLUTES IN WATER o

AV010 CONF 0UNDING EFFECT5 NININIZE CHANGES IN RATE DETERNiNING FACTOR $

OTNER THAN TEMPERATURE l

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N. 30ETHODOLOGY AND DATA REVIEW i

l ASSESS DATA:

ESTER LINKAGE HYDROLYSIS l

Reference:

Golovoy & Cheung (Ford Motor Co.); J Appi Poly i

Sci (1988) h Experiment l

Immersion of polyester in water at varying temperatures 0

(130-210 F) and exposure intervals; determine tensile strength, average molecular weight l'

Material-l Amorphous aromatic polyester, no cross-linking or i

reinforcement o

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II. RAETHODOLOGY AND DATA REVIEW I

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l ASSESS DATA: ESTER LINKAGE HYDROLYSIS i

Resultsc i

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Tensile yield strength remained constant then made rapid transition to failure (yield strain and strain to break coincided) j Limited extent of reaction, one scission per chain, rate l

limiting step is hydrolysis, concentration dependence could be represented as zero order with respect to polymer l

l average molecular weight i

l The logarithm of rate constant showed a linear j

dependence on reciprocal temperature (i.e., followed i

Arrhenius relation) i l

0 Projected service life of polyarylate at 15 C is 76 years t

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11. RAETHODOLOGY AND DATA REVIEW ASSESS DATA: GLASS / POLYMER DEBONDING

Reference:

Phani and Bose; Comp Sci & Tech (1987)

Experiment immersion of FRP in water at varying temperatures (120

- 212 F) for varying time intervals; photomicrographs of 0

material, flexural strength Material-Isophthalic polyester resin, cross-linked, glass reinforced erzmo iz-

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l II. 00ETHODLOGY AND DATA REVIEW

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ASSESS DATA: GLASS / POLYMER DEBONDING l

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Photomicrographs suggest interfacial debonding is main failure mechanism i

i The logarithm of rate of loss of strength showed a linear i

dependence on reciprocal temperature; the magnitude of the activation energy indicated that water diffusion controlled the rate of the process 1

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REVIEW CONCLUSIONS i

CONCLUSIONS i

Hydrolysis of ester linkages and glass / polymer i

debonding are FRP degradatioli mechanisms i

which should be evaluated for long-term i

applications l

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Given the above conclusion, the available data base does not support the Unding that a FRP HIC i

will retain structural stability for 300 years.

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