ML20092N502

Response to Summary Disposition on Eddleman Contention 11 Re Cable Insulation Degradation.Recent Study of LOCA dose-rate Problems Encl.Related Correspondence

ML20092N502
Person / Time
Site:	Harris
Issue date:	06/29/1984
From:	Eddleman W EDDLEMAN, W.
To:	Atomic Safety and Licensing Board Panel
Shared Package
ML20092N499	List: ML20092N498 ML20092N501 ML20092N502 ML20092N507
References
82-468-01-OL, 82-468-1-OL, OL, NUDOCS 8407030213
Download: ML20092N502 (13)

Text

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UNITED STATES OF AMERICA ~ June 29, 198h NUCLEAR BEGULATORY COMMISSION

'84 A -2 P 3 :47 BEFORE THE ATOMIC SAFETY AND LICENSING BOARD

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Glenn O. Bright th6cii Dr. James H. Carpenter James L. Kelley, Cha$rman In the Matter of CABGLINA POWER AND LIGHT CO. et al. )

(Shearon Harris Nuclear Power Plant, )

Unit 1) ) ASLBP No. 82-h68-01

) OL Wells Eddleman's Response to Summary Disposition -

on Eddleman Contention 11 (Cable Insulation Degradation)

Since the Harris plant doesn't evidently use polyethylene cable insulation, I have been trying to track down data on radiation-related degradation of necprene insulation. This has been without success so far, though I was given to understand (by nonwitness experts I asked for information) that radiation-dose-rate related degradation effects do exist in neoprene insulation. Since Harris is using neoprene insulation, I would respectfully suggest that the Board might look into these effects and see if a Board question on such effects is appropriate.

The standards cited by the Staff (R g. G ido 1 33, ANSI N-18.7 (1976)-

ANS-3 2) appear to date from 197C .nd do not take into account the extensive research nerformed on dose; rr t.a related cable For the Board Staff & Applicants .. enclose a copy of a recent degradation since th t time.A study of T.0CA dose-rate problems in 1 Filing date apuroved by NRC Staff counsel, Anplicanis ed n Baxter, and Judge Bright in Judge Kelley's absence. This is. a one day extension since I teceived the Staff 8s response 6/23/84 8407030213'840629 PDR ADOCK 05000400 0 PDR

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- SAND 83-2018C International Symposium on Aging in Tests of Safety Equipment for Nuclear Power Plants Paris, France May 15-16, 1984 The Effect of Aging on EPR Cable Electrical Performance During LOCA Simulations

• L. D. Bustard Sandia National Laboratories  !

Albuquerque, New Mexico, 87185, USA ABSTRACT When exposed to a LOCA environment, some EPR cable materials '

experience substantial moisture absorption and dimensional  :

changes. These phenomena may contribute to mechanical damage of the cable insulation resulting in electrical degradati6n. ,

Recent experiments illustrate that the extent of moisture absorption and dimensional changes during an accident '

simulation are dependent on the EPR product, the " accelerated age," and the aging technique employed to achieve that age.

Results for several commercial EPR materials are summarized. ,

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• This paper was supported by the U.S. Nuclear Regulstory l

l Commission, Office of Reactor Safety Research, as Extt of the l

Qualification Testing Evaluation (QTE) Program (FIN WA-1051)

' being conducted by Sandia National Laboratories, under Interagency Agreement DOE-40-550-75.

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SAND 83-2Ol8C  ;

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International Symposium on Aging in Tests of I f

Safety Equipment for Nuclear Power Plants Paris, France  !

May 15-16, 1984 7

. L The Effect of Aging on EPR Cable Electrical Performance During LOCA Simulations  !

L. D. Bustard  !

Sandia National Laboratories (

Albuquerque, New Mexico, 87185, USA (

I l EXTENDED ABSTRACT When exposed to a LOCA environment, some EPR cable materials i experience substantial moisture absorption and dimer.sional f changes. These phenomena may contribute to mechanical damage  !

of the cable insulation resulting in electrical degradation. f Data is presented illustrating that the extent of moisture l absorption and dimensional changes occurring during an [

accident simulation are dependent on the EPR product, the  !

" accelerated age", and the aging technique employed to achieve j that age.

In one experiment, eight different EPR products were exposed  !

to sequential and simultaneous aging and LOCA simulation tech- E niques. Three of the EPR products (EPR B, C, and E) absorbed relatively small amounts of moisture when compared to the  !

E other fiv". EPR products (EPR A, D, F, 5, and 1483). Dimen- l sional ch..iges occurring during the accident simulation also  ;

depended on the EPR product. In the same experimental  !

! program, four EPR products (EPR D, F, 5 and 1483) were aged to r

l. different " accelerated ages" and then exposed to a simultaneous  !

steam and radiation LOCA simulation. The moisture absorption j of the four EPR products was enhanced by increased " age."  !

In another experiment, two of the EPR products (EPR A and I

.1483) were preconditioned by various radiation doses and dose r rates. The two EPR products were then exposed to three LOCA  :

j-steam simulations in which the oxygen concentration during the (

steam exposures was varied. For EPR A, increasing the pre- l conditioning dose or decreasing the rate at which the dose was j applied resulted in enhanced moisture absorption. Interest- i ingly, moisture absorption for EPR A decreased when oxygen was  !

present during the steam exposure. l i

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As part of another experiment, EPR A and 1483 were Both aged by several different aging acceleration techniques. -

simultaneous and sequential exposuresFollowing to irradiation and accelerated I

elevated temperatures were employed.  !

aging, the EPR samples were exposed to three LOCA simula-tions. The moisture absorption dependence on aging For technique was vastly different for the two EPRs.

EPR-1483, the moisture absorption, percent volume increase, and the degradation of the normalized tensile strength are all maximized by simultaneous irradiation and thermal aging techniques. This behavior was not observed for EPR A.

During recent French /U.S. cooperative research experiments the moisture absorption of EPR D was examined. It also was '

enhanced by simultaneous aging techniques. i In conclusion, the extent of moisture absorption and dimen-sional changes of EPR products during accident simulations j depend on the EPR product, the " accelerated age", and the aging technique employed to achieve that age. i e 1 i

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INTRODUCTION When exposed to a LOCA environment, some ethylene pro- 1 pylene rubber (EPR) cable materials experience substantial moisture and dimensional changes. These phenomena have -

recently been. employed as part of a hypothesis to explain i mechanical damage leading to electrical degradation of EPR aulticonductors during Loss-of-Coolant Accident (LOCA) simulations. It was hypothesized that dimensional swelling  !

of the insulation caused stress buildup within the multi-conductor geometry. When the jacket split to relieve the j stress, the sudden release of constrictive force on the insulators may have caused cracking or breakup of the  !

insulation. Alternatively, sections of insulation which  !

adhered to the jacket during the splitting were pulled away  :

from the conductor.. Bare copper conductors which were l observed are suggestive of such a multiconductor degradation i process. The multiconductor cable did experience substan- l r tial moisture absorption resulting in excessive dimensional i changes during simultaneous steam and radiation LOCA l simulations.1 , l Experiments illustrate that the extent of moisture absorption and dimensional changes duri6g an accident  :

simulation are dependent on the EPR product, the ,

" accelerated age", and the aging technique employed to In this presentation results for several achieve that age. .

commercial EPR materials will be summarized. l MATERIALS i Six commercial EPR products were tested during three  ;

experimental programs. These are identified as EPR A  !

through EPR F. Test specimens for EPR A, B. D, and F were obtained by carefully disassembling multiconductor (A and D) 1 or single conductor (B and F) cables that were received from i the manufacturers. The insulation was carefully stripped from stranded copper conductors.. For EPR C and E, l compression-molded sheets of the EPR insulation were l obtained from the cable manufacturers and cut into strips. l ,

l In addition to the commercial cable materials, an EPR l formulation used in Sandia National Laboratories i fire-retardant aging studies 2, 3 (EPR-1483) was tested, as l well as an EPDM formulation used in Japanese research '

tests 4 (Japanese UPR-5). Both of these materials were in the form of compression-molded sheets which were cut into strip tensile specimens.

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EPR C, D, and F. EPR-1483, and the Japanese EPR-5 are j fire-retardant EPR insulations. For EPR A, B, and E. Hypalon  ;

jackets are used to provide fire-retardancy to the cable l construction.  !

Characteristics of the various EPR products are summarized i in Table 1. f EXPERIMENTAL TECHNIOUES ,

Two experimental programs have been reported. An addi- l j

tional experimental program is in progress. Gillen, et al.5 exposed two EPR materials (EPR A and EPR-1483; reported in their report.as EPR and EPR-5 respectively) to LOCA simulation i tests in which the oxygen concentration-during the LOCA expo-  :

sures was an experimental variable. Prior to performing the  ;

LOCA simulations, different radiation doses and dose rates  ;

were used to " age" the specimens. Moisture absorption and l

., tensile properties were monitored during their testing program.

We also monitored these parameters.1 We performed three LOCA simulations: obtaining data for each of the eight EPR  !

materials (EPR A through F. EPR-1483, and the Japanese EPR-5).  ;

The effects of EPR product, accelerated

• age, and aging tech-nique were investigated. Because of experimental limitations,  ;

some experiments were performed for only a few of the EPR i materials.

Currently in Cooperative t ResearchProgram.grogressisaFrench/U.S.

EPR C and D (EPR 1 and 2, respectively,  !

in the Cooperative Program) were aged by five different aging  !

• techniques. These specimens, as well as unaged specimens, are [

being exposed to six different LOCA accident simulations at the 'rench CESAR facility. Moisture absorption and d$ men-l sional changes for the EPR samples are being monitored during testing. ,

l RESULTS [

The influence of EPR product on moisture absorption (as f i determined by weight gains) is shown in Table 1 (Reference i 1). EPR B, C, and E absorbed relatively small amounts of [

l moisture when compared to EPR A, D F. EPR-5, and EPR-1483. '

Dimensional increases are also shown in Table 2 (Reference l 1). An EPR product dependence is also evident. [

The effect of " accelerated age" on EPR moisture absorption  !

is demonstrated by Table 3. The moisture absorption by EPR D. l F. EPR-5, and EPR-1483 is enhanced by the accelerated age (Reference 1), i f

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l The aging procedures employed for Tables 2 and 3 included ,

both radiation and thermal-stress environments. In contrast, l

- Table 4 illustrates moisture-absorption data for two EPR '

products which were preconditioned using single-stress irradi-ation exposures 5 The LOCA environments for Table 4 were vastly different than those employed for Tables 2 and 3. (The accident simulations did not include irradiation; the steam 4

profiles were different.) Therefore, cross comparicons of

. moisture-absorption magnitude should not be made. The  ;

influence of radiation exposure on EPR A's behavior is clear, i especially at the larger total doses or the lower dose rates, where moisture absorption is enhanced with respect to the l unaged specimens. Interestingly, oxygen presence during the  ;

LOCA simulations reduced EPR A's moisture absorption. For  !

EPR-1483, only larger dose rates were employed as part of the  !

exneriment. A 22 Mrd irradiation did not enhance EPR-1483's  !

moisture absorption. Neither the 22 Mrd irradiated nor the  !

unaged specimens absorbed significant moisture.  !

e We also showed the effect of aging technique on EPR A and l EPR-1483.1 Both EPR A and EPR-1483 were aged by ight '

I different techniques and then exposed to three different LOCA simulations. During the LOCA simulations, several of the EPR  !

A samples experienced reversion and loss of form. Dimensional l and weight measureme'nts were therefore not always possible;  !

tensile measurements were not attempted. In contrast, EPR-1483 did' maintain its form allowing for dimensional, .

weight, and tensile measurements.  !

l Figure 1 illustrates EPR A's moisture absorption for vari-  !

ous aging and accident simulations.7 Figure 2 provides i similar data for EPR-1483. The moisture-absorption dependence  !

on aging technique is vastly different for the two EPR pro-ducts. Figures 3 and 4 illustrate that the percent volume l  ;

increase and degradation of the normalized tensile strength for EPR '.483 are maximized by the simultaneous irradiation and  ;

thermal aging techniques (7d T + R; 30d T + R). Figure 5  !

replots the moisture absorption and tensile strength, T/To, ,

data for EPR-1483 to illustrate the inverse relationship  !

between these two parameters. The percent volume change of  ;

L EPR-1483 is also inversely related to the tensile strength.  !

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! EPR C and EPR D were aged by five different aging tech- i niques as part of the French /U.S. Cooperative Research Program. These specimens,-as well as unaged specimens, were i exposed to a simultaneous irradiation and steam exposure at  !

the French CESAR facility. A nitrogen gas overpressure was l' applied during the steam exposure; all air was removed. The EPR C specimens absorbed negligible moisture, consistent with  !

our previous conclusion that EPR C absorbs relatively small I amounts of moisture when compared to some other EPR products. {

l The EPR D moisture absorption was enhanced by simultaneous  :

thermal and irradiation aging :echniques (Figure 6). This is t consistent with EPR-1483 results shown in Figure 2.

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DISCUSSION j Some EPR cable materials experience substantial moisture absorption and dimensional changes when exposed to the steam  ;

environments of postulated Loss-of-Coolant Accidents. We  :

hypothesize that dimensional swelling of the insulation can i causs stress buildup within multiconductor geometries some- l times resulting in Mechanical damage leading to cable electri-  ;

cal. degradation. Recent experiments on tensile specimens  !

illustrate that the extent of moisture absorption and dimen- ,

sional changes during an accident simulation are dependent on l the EPR product, the " accelerated age", and the aging technique employed to achieve that age. Thus, the choice of these parameters will help determine the extent of stress buildup within multiconductor geometries.

For one EPR material EPR-1483, the extent of moisture i absorption and dimensional changes is clearly ' correlated to l

.- degradation of the ultimate tensile strength.

REFERENCES

1. L. D. Bustard, "The Effect of LOCA' Simulation Procedures on Ethylene Propylene Rubber's Mechanical and Electrical Properties." NUREG/CR-3538, SAND 83-1258 October 1983. i I

2. E. A. Salazar D. A. Bouchard, D. T. Furgal, " Aging with l Respect to Flammability and Other Properties in Fire-  !

Retardant Ethylene Propylene Rubber and Chlorosulfonated  :

Polyethylene," NUREG/CR-2314, SAND 81-1906, March 1982. ,

3. R. L. Clough, " Aging Effects on Fire-Reterdant Additives in !

Organic Materials for Nuclear Plant Applications,"  !

NUREG/CR-2868, SAND 82-0485, August 1982. ll

4. Material obtained from Dr. T. Se9uchi of the Japan Atomic ,

Energy Research Institute.

5. K. T. Gillen, R. L. Clough, G. Ganouna-Cohen, J. Chenion,  !

and G. Delmas.-"The Importance of oxy 7en in LOCA Simulation ,

Tests," Nuclear Engineering and Design 74, 271-285, (1982). j

6. L. D. Bustard, "U.S./ French Cooperative Research Program:  !

U.S. Test Results for Cable Insulation and Jacket Materials  !

at the Completion of Accelerated Aging." SAND 83-2019C. I f

7. Moisture absorption data for EPR A during LOCA simulations ,

was not presented in Reference 1 but was obtained as part l of the experimental effort described in Reference 1. }

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EPR MATERIAL -

t Characteristic A B C D E F 1483 5  !

l' Experimental Samples

• Extruded X X X X Compression Molded X X X X

Commercial Product Status

. Single Conductor X X

j Multiconductor X X X X X Non-Commercial or X X 9 Unknown Fire-Retardancy j Within EPR Formulation X X X X X ,

.i f, Hypalon Jacket X X X  ;

a e j Cross-Linking Technique Chemical X X X X X X Irradlation X X l Table 1: Characteristics of EPR Products i

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Table 2 Insulation Specimens: Percentage Weight Increases and ,

Dimensional Increases (O.D./ Length or Width / Thickness / Length j Cable Sequential Simultaneous Simultaneous  ;

Material Test

• Test #1* Test #2** i Percentage Weight Increases  !

EPR A +50  ?  ;

EPR B +4 -1 EPR C +9 +23  ;

EPR D +121 +173 +172 EPR E +0 +7 t EPR F +94 ,

EPR-5 +77 EPR-1483 +55 +45 I

Percentage Dimensional Increases l l

EPR A +19/0  ? j EPR B -18/0 -5/0 i EPR C +5/+20/0 +7/e20/+5  ;

EPR D +38/+5 +53/+35 +51/+42 I EPR E +2/0/0 0/0/0 f i

EPR F +31/+19  !

i j EPR S +18/+30/+21 [

EPR-1483 +17/+46/+7 +20/+46/+16  !

• Both the sequential and simultaneous #1 LOCA profiles were i interrupted at day 9 by an unanticipated steam cooldown. I The test was continued and measurements were made at the '

I and of 21 days of steam exposure.  !

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• • Measurements made during unanticipated steam cooldown starting at day 16 of LOCA profile.

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I Table 3 The Effect of " Accelerated Age" on EPR  !

Moisture Absorption During Simultaneous Steam and Irradiation LOCA Simulation (Reference 1)

EPR Material Accelerated Age Moisture Absorption

(% Weicht Increase) i EPR D Unaged 16 40-yr equiv* 172 EPR F Unaged 20 40-yr equiv* 94 Japanese EPR-5 Unaged 49 40-yr equiv* 77 EPR-1403 Unaged 17 5-yr equiv** 22 40-yr equiv*** 67 Table 4 The Effect of " Radiation Agieg" on

• EPR Moisture Absorption During Slevitaneous Steam and Oxygen LOCA Exposures (R6ference 5)

EPR Aging LOCA 02 Moisture Absorption Meterial Condition Coltent (%) (% Weicht Increase)

EPR A

• Unaged 5 22 Mrd S 909 krd/h 0 8 26 Mrd S 27 ktd/h 0 23 47 Med S 927 krd/h 0 19 Unaged 10 3 22 Med S 909 krd/h 10 9 ,

26 Mrd 9 27 krd/h 10 10 47 Mrd S 927 krd/h 10 7 Unaged 21 4 22 Mrd S 909 krd/h 21 12 26 Mrd 0 27 krd/h 21 10 47 Mrd S 927 krd/h 21 9 EPR-1403 Unaged 0 1 22 Mrd 9 927 krd/h 0 1 i

Unaged 21 0 22 Mrd 9 927 krd/h 21 1 ,

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• A 74 139'c thermal exposure with simultaneous irradiatiGn for 6 6 to 40 Mrd (air-equiv.).

• • A 94 h simultaneous exposure to 120*C and 4.9 Mrd (air-equiv.).

• • • A 30 d slaultaneous exposure to 120*C and 39 Med (air-equiv.). l

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i I O= STEAM ONLY LOCA REY: A = SIMULTANEOUS STEAM AND IRRADIATION (113 230 O = STEAM ONLY LOCA Mrd air-equiv.) LOCA ,

m = SEQUENTIAL IRRADIATION E = SEQUENTIAL 1RR ADI ATION l (127210 Mrd air-equiv.) (127210 Mrd air-equiv.)

TMEN STEAM LOCA TMEN STEAM LOCA O E gg ,

S ye egdv. 8 yr equiv.

1 o B 94 h T+ R' 94 h T + R  ;

40 yr ogdv. 40 yr egulv. I 7dT+R 8 8 Td T+R' sod T + R' E 30d T+R' a l a

28d T-284 Rs 38d R-28d 7 8 5 28d T-28d R8 28d R-28d Ts Oh o

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4 0 E 28d T-SSh R 28d T-55h R' <

A  !

85h R-28d T* E 85h R-28d T* 11

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, t , t , t , i O 20 40 SO 80 0 20 40 60 80  !

Y WEIGNT GAIN  % WEIGNT GAIN ,

NOTES: 1: 120*C and 53 krd/h (air-equiv.)

NOTES: b 120*C and 63 ktd/h (air-eeulv.)130'C enet 250 ktd/h (eir-equiv.) 2: 139'C and 250 krd/h (alt-equiv.)  ;

S: 120'C; 67 krd'h (alt-equiv.) 3: 120*C; 57 krd/h (air-equiv.)  ;

4: 120*C; 760 krd/h (air-equiv.)

4: 120'C; 750 ktd/h (ser-eguh.)

Fig. 1. Effect of Aging and Accident Fig. 2. Effect of Aging and Accident j Accident Techniques on EPR A's Techniques on EPR-1483's Weight

• Weight Gain (Moisture Absorption) Gain (Meisture Absorption) i 6

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NEY:

A= AGED O = 0 TEAM ONLY LOCA O= AGED FOLLOWED BY STEAM a= SsMULTAMEOUS STEAM AND IRRADIAT10N ONLY LOCA i (113 30 Mrd aer-egsev.) LOCA a = AGED FOLLOWED BY a = SE00ENTIAL teRADI ATION (127 *10 Mrd SIMULTANEOUS STEAM AND '

elr-eaystv.) TMEN STEAM LOCA BRRADIATION LOCA UISASED E = AGED FOLLOWED BY I

SEQUENTIAL IRR ADIATION S yr egulv. , TMEN STEAM LOCA 94h T + R UNAGED A 40 ye egelv.

707+R 8 5 yr egulv. '

i SM T + R' 94 h T + R' 284 T-284 R' O 8 40 yr ogdv. '

Sed R-284 T' o 8 7d T+R8 384 T-SSh R' 3 A Il S0d T+ R' 88""'I" 0 ' 28d T-28d Rs

,1 , e s' s i e to 40 to to too 120 28d R-28d T 8 '

% VOLUME INCREASE 28d T-55h R' ge0TES: 1: 120*C and 53 krd/h (ear-eeAJ 2: 139*C and 250 krd/h (ser-oosevJ SSh R- 28d T*

• l , t , l , I 3: 120*C: 87 krd/h (alr-eestv3 ,

4: 120*C; 700 krd/h (air-egssy.) 1.1 0.9 0.7 0.5 0.3 NORMAuzte TsNSn.m STRENGTH (T/T.)

NOTES: 1: 120'C and 53 krd/h (alt-equiv.)

2: 139'C and 250 ktd/h (air-equiv.)

3: 120*C: 57 krd/h (alt-equiv.)

4: 120*C; 760 ktd/h (air-equiv.)

Fig. 3. Effect of Aging and Accident Fig. 4. Effect of Aging and Accident Techniques on t Volume Change Techniques on Normalized of EPR-1483 Tensile Strength of EPR-1483 i

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, i , i W 10 A = SIMULTANEOUS 0 0 10 20 SO 40 50 0 0  % WElGHT GAIN O = SEQUENTIAL O C NOTES: 1: if d 120*C and ~65 krd/h (alf-equiv.)

O = STEAM ONLY 2: 16d 70'C, ~65 krd/h (air-equiv.) and

-10 16d 120*C 0.3 0.4 0.6 0.6 0.T 0.6 0.9 1.0 1.1 S: 16d 27'C, ~65 krd/h (alr-equiv.) and ULTIMATE TENSILE STRENGTH (T/T.)

16d 120*C Fig. 5. Relationship Between weight Fig. 6. Effect of Aging Techniques Changes (Moisture Absorption) on Moisture Absorption (4 for EPR-1483 and the Normalised weight Gain) of EPP During Ultimate Tensile Strength at the Simulataneous 60 Mrd and Completion of the Accident Steam (w/o Air) Exposure. -

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