ML20062H658
| ML20062H658 | |
| Person / Time | |
|---|---|
| Site: | Allens Creek File:Houston Lighting and Power Company icon.png |
| Issue date: | 07/29/1980 |
| From: | Shirley N GENERAL ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML19331C559 | List:
|
| References | |
| ISSUANCES-CP, NUDOCS 8008190343 | |
| Download: ML20062H658 (9) | |
Text
Ut1ITED STATES OF AMERICA oV NUCLEAR REGULATORY CCt41ISSI0tt BEFORE THE AT0f1IC $AFETY At:0 LICEilSING BOARD In the Matter of HOUSTON LIGHTING & POWER COMPANY )
)
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Docket No. 50-466 (Aliens Creek Nuclear Generating )
Station, Unit No. 1)
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AFFIDAVIT OF N0EL C. SHIRLEY State of California County of Santa Clara I, !!oel C. Shirley, Senior Licensing E.1ganeer, 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.
Executed at San Jose, Calfornia, July 29,1980.
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Subscribed and sworn to before me this 29 day of July,1980, mee:c:e:e:e:c,eee:e:ex:e e.w M
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I UNITED STATES OF AMERICA 7
UUCLEAR REGULATORY COMMISSICN BEFORE TEE ATCMIC SAFETY AND LICENSING BOARD In the Matter of S
S HOUSTON LIGHTING & PCWER S
COMPANY S
Occket No. 50-466 S
(Allens Creek Nuclear S
Generating Station, Un_t 5
i No. 1)
S Affidavit of Noel C.
Shirley My name is Noel Shirley.
I am employed by General Electric Company as a Senior Licensing Engineer.
I have served 4.n this capacity for 6 years.
A statement of my experience and qualifications is set out in Attachment 1.
This affidaviu addresses McCorkle Contention No.
14, in which Intervenor states that the fuel desien for ACNGS is not safe because it is subject to hydriding and densification.
Intervenor contends that hydriding and i
densification will cause failures in the ACNGS fuel red cladding and an increase in offgas activity.
The cause of hydriding induced fuel rod failure in GE Zircaloy clad 3WR fuel has been due to internal attack of the cladding by hydrogen.
Hydride attack will occur only when the hydrogen is inside the fuel rod.
The source of hydrogen inside the rod has been contamination of the fuel a
D9 4
by moisture or other hydrcgenous materials during manufacture.
The clad defects have occurred primarily at low fuel burnup, and appear as localized blisters that may perforate the clad. ~2/
Hydriding induced fuel rod failures were first found in the late 1960's at several operating BWRs.
An extensive research program identified the cause of the failures, and provided the basis for the introduction of improvements in the manufacturing process to preclude the i
recurrence of the problem'in newly manufactured fuel. -3/
In order to prevent hydrogen contamination of the inside of the fuel rod, two major changes have been made in the manufacturing process.
A hot vacuum outgassing system was installed in the Wilmington fuel manufacturing facility to remove moi.sture from the fuel and rod just prior to i
welding the end plug of the red in place.
The outgassing s
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 getter in the form of Zirconium alloy chips has been installed inside the fuel rod to preferentially combine with hydrogen present in the red.
These chips are contained in an open stainless steel tube placed inside the fuel red. -2/
No hydride induced failures have occurred in fuel manufactured using the hydrogen getter and refined outgassing Ch.e(d
-9
techniques.
Hydriding has been effectively eliminated as a 1,2,5/
fuel failure mechanism in General Electric BWR fuel.
In 1972, densification of the UO fuel was identified 2
us a concern in fuel design.
Five specific concerns were identified due to observed and/or postulated effects.
They were:
1.
Increased linear heat generation rate due to a decreased fuel column height with essentially constant heat generation in the pellet.
2.
Decreased heat transfer capability between the fuel pellet and the clad due to the creation of a wider fuel to clad gap as the pellet shrinks.
3.
Increased stored energy in the fuel caused by the increased linear heat generation rate and lowered pellet to clad thermal conductance.
I 4.
Power spikes caused by the creation of axial gaps as the pellets shrink.
5.
Cladding collapse into fuel column gaps caused by pellet axial shrinkage. ~3/
Intervenor relies primarily on Items 1 and 4 in support of the contention; however, all five items are interrelated.
The causes of in-reactor fuel densification are new well understood.
This knowledge has led to quality control p.- -.521
tests during manufacture which assure that the fuel is of such an initial density that further densification during irradiation does not adversely effect the thermal-mechanical performance of 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.
These densities are compared with the theoretical maximum density.
This process assures that the maximum amount of densification during the irradiation is controlled to an acceptable level.-6/
This level of densification is considered in fuel design and safety analysis to address the 5 concerns identified above.
Conservative limits have also been placed on the Linear Heat Generat'.on 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 are issued by the NRC as part of the operating license for the plant.
With regard to densification induced axial gap formation several techniques were used to quantify the size, if any, of axial gaps in SWR fuel rods.
In-reactor neutron flux scans were
_4_
. 9 <>
D hd N
used at operating power plants to measure the actual peaks in neutron flux that would occur if axial 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
{
f the fuel rod.
If an axial gap exists, a spike in the gamma radiation will be detected in the opposite side of the fuel rod.
In addition, post-irradiation neutron radiography and j
gamma scans were performed at General Electric laboratories, The results of all these tests showed that axial gap formation either does not occur, or that only very small gaps are formed of a size insufficient to comprcmise fuel integrity.
It should be noted that no fuel cladding failures or collapses attributable to censification have ever occurred in BWR fuel. -1/
1 If, in spite of all indications that hydriding and densification will not be fuel rod failure mechanisms for ACNGS, clad perforations do occur, no genuine safety concern exists.
Extensive experience in the operation of reactor coolant and/or the offgas system can be controlled by regulating the power level of the reactor. ~3/
If necessary, the reactor can be shut down and the failed fuel replaced.
This ensures that radioacrivity released from the plant is always well within regulatory requirements as delineated in the ACNGS Technical Specifications. 523
In summary, Intervenor has offered only an unsupported contention that hydriding and densification problems make the ACNGS _ col unsafe.
Explicit consideration of fuel densification is used in fuel design and safety analyses and the effects of fuel densification are reflected in the plant Technical Specifications.
Further, new production techniques
]
4 and extensive testing have shown that these two concerns are not potential fuel failure mechanisms for ACNGS.
I i -91 D-
References 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 t
VR Fuel Through September,1971," NEDO-10505, :tay, l
3.
" General Electric Boiling Water Reactor Generic Reload app.. cation for 3 x 8 Fuel," N2DO-20360, April, 1974.
4.
ACNGS PSAR, Section 4.2.1.3.4.6 and 4.2.1.3.4.9.
5.
- Elkins, R.
B., " Experience with BWR Fuel Through December, 1976," NEDO-21660, July, 1977.
6.
- Meyer, R.
0.,
"The Analysis of Fuel Densification'"
NUREG-0082, July, 1976.
1 i
e 525
ATTACHMENT I PROFESSIONAL QUALIFICATIONS OF N0EL C. SHIRLEY _
POSITION:
Senior Licensing Engineer i
EDUCATION:
B.S. - Business Science,1960, San Francisco State B.S. - Engineering,1961, San Francisco State M.3. - Management Science,1967, San Francisco State ADDITICNAL BACKGROUND:
Professional Engineer, California (License NU 1388)
Guest Lecturer, Civil Defense Preparedness Agency, Staff College, Battle Creek, Michigan, 1973-1976 EXPERIENCE:
From 1965 through 1967 I was a Design Engineer responsible for the design er.d fabrication of the containments of prototypical fuel assemblies, scheduled for experimental modification ia the GETR, MTR, TREAT and EBR-II. As such I used the physical and nuclear properties of the fuel assembly in designing the c::ntainment for the assembly.
From February,1971 through September,1974 I was the Specialist-Licensing and Transportation for the Midwest Fuel Recovery Plant (MFRP).
In this capacity I was responsible for both the genera-tion and maintenance of the AEC issued license to receive and store spent reactor fuei at the MFRP.
I also was responsible for the transportation of all spent fuel shipped to the MFRP.
From October,1974 through September,1979 I was a Senior Licensing Engineer in Gf's in Bethesda office.
In this capacity I interacted directly with both the NRC and the Advisory Committee on Reactor Safeguard on fuel related issues affecting G.E.
From October,1977 to present I have been a Senior Licensing Engineer in the Safety and Licensing Operations BWR Systems Licensing Subsec-tion.
In this capactty I am responsible for all Generic Licensing Issues a ffecting BWR fuel.
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