ML20031H353

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Testimony of Nc Shirley Re Mccorkle Contention 14 on Fuel Rod Hydriding.Discusses New Info on Fuel Hydriding Since ASLB 810901 Order.Hydriding Effectively Eliminated as Fuel Failure Mechanism
ML20031H353
Person / Time
Site: Allens Creek File:Houston Lighting and Power Company icon.png
Issue date: 09/18/1981
From: Shirley C, Shirley N
GENERAL ELECTRIC CO., HOUSTON LIGHTING & POWER CO.
To:
Shared Package
ML20031H319 List:
References
NUDOCS 8110270398
Download: ML20031H353 (2)
v • d • e


Text

Scptcmbrr 18, 1981 1

UNITED STATES OF AMERICA' NUCLEAR REGULATORY COMMISSION 2

BEFORE THE ATOMIC SAFETY AND LICENSING BOARD 3

In the Matter of S

S HOUSTON LIGHTING & POWER COMPANY S

Docket No. 50-466 S

i (Allens Creek Nuclear Generating S

6 i Station, Unit 1)

S 7

DIRECT TESTIMONY OF NOEL C.

SHIRLEY REGARDING MCCORKLE CONTENTION 14 -

FUEL ROD HYDRIDING 9

Shirley, have you reviewed your prior affidavit Q.

Mr.

10 on McCorkle Contention No. 14, which affidavit is attached 17 hereto as Attachment NCS-l?

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17 A.

Yes I have.

Are the statements contained in the affidavit still 13 Q.

14 true and correct?

A.

Yes, except for the changes described in the errata 13 attached hereto as Attachment NCS-2.

g In the Board's Order of September 1, 1981, a Q.

17 question was raised au to whether there is any more recent IS information on fuel hydriding.

Can you address this question?

Q.

Since the original affidavit was filed, two documents 7e

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20 have been issued which bear upon this contention.

The first 21 document (NEDE-24343-P) was prepared and issued by the General Electric Company and is entitled "Experienca with BWR Fuel 22 l

Through January 1981."

This report is dated May 1981.

The i

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l 8110270398 810919-i (DRADOCK 05000466 j

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second document (NUREG/CR-1818) was prepared and issued by 1

2 the Nuclear Regulatory Commission and is entitle,d " Fuel 3

Performance Annual Report for 1979".

This report was 4

published in January 1981.

My review of these reports indicates that the g

statements contained in my affidavit are still correct.

To o

reiterate, hydriding has been effectively eliminated as a i

fuel failure mechanism, and there have been no fuel cladding 3

failures in a BWR attributable to densification.

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,12 13 14 15 16 17 18 19 20 21 22

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Attachm nt NCS--l i

UtlITED STATES OF AMERICA

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NUCLEAR REGULATORY COMMISSION i

I BEFORE THE ATOMIC SAFETY AND LICENSING BOARD l

In the Matter of t

HOUSTON LIGHTI!1G & POWER COMPANY

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Docket No. 50-466 (Allens Creek Nuclear Generating )

g Station, Unit No. 1)

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AFFIDAVIT OF N0EL C. SHIRLEY r

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State of California County of Santa Clara I

j I, floel C. Shirley, Senior Licensing Engineer, within the Safety and Licensing Operation of the General Electric Company, of lawful age, being first duly sworn, upon my oath certify that the statements contained in the attached pages and accompanying exhibits are true and correct to the best of my knowledge and belief.

r-Executed at San Jose, Calfornia, July 29, 1980.

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Subscribed and sworn to before me this 29 day of July, 1980.

mmmcecencocecocemcoceaece; h

OFFICIAL SEAL f

y M., k KAREN 5. VOGELHUBER 0

M g yg-p Nota *Y PUBUC.CAUFORNIA g

- fl0TMY PUBLIC Ill AliD FORfAID SANTA CLARA COUNTY g COUNTY AND STATE g

My Cc g c>ccac:mmission Expires Dec. 5,1980 g

~c ccccaocanawmosanacs My commission expires

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j Attachment NCS-1 I

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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION k

BEFORE THE ATOMIC SAFETY AND LICENSING BOARD I

In the Matter of S

S HOUSTON LIGHTING & POWER S

COMPANY S

Docket No. 50-466

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S (Allens Creek Nuclear S

Generating Station, Unit S

g No. 1)

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Affidavit of Noel C.

Shirley p

My name is Noel Shirley.

I am employed by General Electric Company as a Senior Licensing Engineer.

I have t

served in this capacity for 6 years.

A statement of my experience and qualifications is set out in Attachment 1.

b This affidavit addresses McCorkle Contention No.

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14, in which Intervenor states that the fuel design for L

ACNGS is not safe because it is subject to hydriding and l

densification.

Intervenor contends that hydriding'and I

densification will cause failures in the ACNGS fuel rod L-cladding and an increase in offgas activity.

t The cause of hydriding ind?.ced fuel rod failure in GE Zircaloy clad BWR fuel has been due to internal attack of the cladding by hydrogen.

Hydride attack will occur only I

when the hydrogen is inside the fuel rod.

The source of hydrogen inside the rod has been contamination of the fuel 4-I E

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i by roisture or other hydrogenous materials during manufacture.

The clad defects have occurred primarily at low fuel burnup, t

and appear as localized blisters that may perforate the clad. ~2/

Hydriding induced fuel rod failures were first

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found in the late 1960's at several operating BWRs.

An extensive research program identified the cause of the I

failures, and provided the basis for the introduction of improvements in the manufacturing process to preclude the l

recurrence of the problem in newly manufactured fuel.-3/

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In order to prevent hydrogen contamination of the inside of'the fuel rod, two major changes have be:n made in i~

the manufacturing process.

A hot vacuum outgassing system was installed in the Wilmington fuel manufacturing facility I

to remove moisture from the fuel and rod just prior to welding the end plug of the rod in place.

The outgassing c

technique was refined through February, 1973, with the outgassing time and temperature being increased from that initially used.

In addition, since March, 1972, a hydrogen ge*.ter in the form of Zirednium alloy chips has been installed i

inside the fuel rod to preferentially combine witi hydrogen present in the rod.

These chips are contained in an open

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stainless steel tube placed inside the fuel rod.-2/

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No hydride induced failures have occurred in fuel manufactured using the hydrogen getter and refined outgassing k.. !l.

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techniques.

Hydriding has been effectively eliminated as a 1,2,5/

fuel failure mechanism in General Electr:.c BWR fuel.

In 1972, densification of the_UO fuel was identified 2

as a concern in fuel design.

Five specific concerns were i

identified due to observed and/or postulated effects.

They i

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were:

1.

Increased linear neat generation l

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rate due to a decreased fuel column height with essentially constant heat generation in the pellet.

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'l 2.

Decreased heat transfer capability between the fuel pellet and the clad due to i

the creation of a wider fuel to clad gap as l

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the pellet chrinks.

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3.

Increased stored energy in the fuel l

L caused by the increased linear heat generation I

rate and lowered pellet to clad thermal conductance.

I 4.

Power spikes caused by the creation of axial caps as the pellets shrink.

5.

Cladding collhpse into fuel column 3l L

gaps caused by pellet axial shrinkage.

Intervenor relies primarily on Items 1 and 4 in support of the L

contention; however, all five items are interrelated.

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The causes of in-reactor fuel densification are now well understood.

This knowledge has led to quality control 1 E p

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tests during manufacture which assure that the fuel is of such i

g an initial density that further densification during irradiation

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does not adversely effect the thermal-mechanical performance of I

l the fuel.

Sample manufactured fuel pellets are removed from the production line and are resintered (baked).

Tests are then made to determine the actual density of the resintered sample.

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These densities are compared with the theoretical maximum density.

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This process assures that the maximum amount of densification I-during the irradiation is controlled to an acceptable level.-6/

This level of densification is considered in fuel design and I

safety analysis to address the 5 concerns identified above.

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Conservative limits have also been placed on the Linear Heat Generation Rate (LHGR) allowed in the reactor fuel.

These limits assure that the actual LHGR will remain within design limits if maximum theoretically possible densification occurs.

ACNGS will comply with any limits that are in force when it begins operation through restrictions that are part of the plant Technical Specifications.

The Technical Specifications

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are issued by the NRC as part of the operating license for the plant.

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With regard to densification induced axial gap formation several techniques were used to quantify the size, if any, of

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axial gaps in BWR fuel rods.

In-reactor neutron flux scans were' e !

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used at operating power plants to measure.the actual peaks in neutron flux that we ld occur if axi i gaps existed.

Gamma scans of irradiated fuel rods were made at reactor sites.

In a gamma scan a steam of gamma rays is directed.at r

the fuel rod.

If an axial gap exists, a spike in the gamma l

l radiation will be detected in the opposite side of the fuel

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rod.

In addition, post-irradiation neutron radiography and gamma scans were performed at General Electric laboratories, The results of all these tests showed that axial gap formation g

either does not occur, or that only very small gaps are l

formed of a size insufficient to compromise fuel integrity.

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It should be noted that no fuel cladding failures or collapses 1

attributable to densification have ever occurred in BWR 1/

fuel.

If, in spite of all indications that hydriding and

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densification will n'ot be fuel rod failure mechanisms for ACNGS, clad perforations do occur, no genuine safety concern exists.

Extensive experience in the operation of reactor

'g-coolant and/or the offgas system can be controlled by regulating i

the power level of the reactbr.1/

I If necessary, the reactor can be shut down and the failed fuel replaced.

This ensures that radioactivity released frca the plant is always well within regulatory requirements as delineated in the ACNGS i

Technical Specifications. t, L.

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I In summary, Intervenor has offered only an unsupported I

contention that hydriding and densification problems make i

the ACNGS fuel unsafe.

Explicit consideration of fuel densification is used in fuel design and safety analyses and I

the effects of fuel densification are reflected in the plant Technical Specifications. 'Further, new production techniques I

and extensive testing have shown that these two concerns are not potential fuel failure mechanisms for ACNGS.

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I References i

t 1.

Elkins, R.

B., " Experience with BWR Fuel Through September, 1974," NEDO-20922, June, 1975.

2.

Ditmore, D.

C.-and Williamson, H.

E.,

" Experience with g

BWR Fuel Through September, 1971," NEDO-10505, May, F

1972.

I 3.

" General Electric' Boiling Water Reactor Generic Reload Application for 8 x 8 Fuel," NEDO-20360, April,.1974.

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'4.

ACNGS PSAR, Section 4.2.1.3.4.6 and 4.2.1.3.4.9.

I 5.

Elkins, R.

B., " Experience with BWR Fuel Through December, i

g 1976," NEDO-21660, July, 1977.

.f 6.

Meyer, R.

O.,

"The Analysis of Fuel Densification,"

NUREG-0085, July, 1976.

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ATTACHMENT I p

1 PROFESSIONAL QUALIFICATIONS OF NOEL C. SHIRLEY

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I POSITION:

Senior Licensing Engineer r

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EDUCATION:

B.S. - Business Science,1960, San Francisco State j

j B.S. - Engineering,1961, San Francisco State M.S. - Management Science,1967, San Francisco State l

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1 ADDITI'UNAL BACVGROUND:

Professional Engineer, California (License NU 1388)

I Guest Lecturer, Civil Defense Preparedness Age.1cy, r -

' Staff College, Battle Creek, Michigan, 1973-1976 I

EXPERIENCE:

Fr:m1965 through 1967 I was a Des.ign Engineer responsible for the 1

design and fabrication of the containments of prototypical fuel c

assemblies, scheduled for experimental modification in the GETR, MTR, TREAT and EBR-II. As such I used the physical and nuclear

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properties of the fuel assembly in designing the containment for tha assembly.

l Frou February,1971 through September,1974 I was the Specialist-Licen:Ing and Transportation for the Midwest Fuel Recovery Plant (MFRP).

In this capacity I was responsible for tOth the genera-tion and maintenance of the AEC issued license to receive and store spent reactor fuel at the MFRP.

I also was responsible for the transportation of all spent fuel shipped to tile MFRP.

From October,1974 through September,1979 I was a Senior Licensing Engineer in Gf's f n Bethesda office.

In this capacity I interacted directly with both the and the Advisory Cor.nittee on Reactor Safeguard on fuel relateu issues affecting G.E.

From October,1977 te present > have been a Senior Licensing Engineer in the Safety and Licensing Or.eiations BWR Systems Licenring Subsec-tion.

In this cipacity I am responsible for all Generic Licensing 1ssues affecting BWR fuel.

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4 Attachment NCS-2 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In tha Matter of S

S HOUSTON LIGHTING & POWER COMPANY S

Docket No. 5G-466 S

(Ailens Creek Nuclear Generating S

Station, Unit 1)

S AFFIDAVIT OF NOEL C. SHIRLEY ERRATA

p. 3:

Delete the paragraph which begins on Page 3 and ends on Page 4, and substitute the following:

The in-reactor fuel densification mechanism is well 1

understood.

This knowledge has enabled _ modification of pellet manufacturing process parameters to control pellet in-reactor densification to an acceptable level.

Verification that the process parameter modifications are effective in controlling in-reactor densification is provided through the performance of a pel3et resintering test as a routine quality control step in the manufacturing process.

This resintering test has been demonstrated to conserva-tively characterize the extent and kinetics of in-reactor densification.6/

The level to which pellet in-rcactor densification is controlled is explicitly employed in fuel design and safety analyses to address the 5 concerns identified above.

p.

4; second paragraph:

The sentence that raads: "These limits assure that actual LHGR will remain within design limits if maximum i

theoretically possible densification occurs."

should be changed to raad:

These limita assure that the actual LHGR will remain within design and safety limits when the postulated densification effects are con 9idered.

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p.

5, b. 4:

The word " steam" should read " stream".

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