ML20062H543

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Affidavit in Support of Summary Disposition of Jf Doherty Contention 15 Re Use of Wigle Computer Code.Criteria of Spert Rept (IN-1370) Irrelevant to Scram Reactivity Calculations.Prof Qualifications Encl.Pp 150-155
ML20062H543
Person / Time
Site: Allens Creek File:Houston Lighting and Power Company icon.png
Issue date: 07/29/1980
From: Schardt J
GENERAL ELECTRIC CO.
To:
Shared Package
ML19331C559 List:
References
ISSUANCES-CP, NUDOCS 8008190103
Download: ML20062H543 (6)
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Text

h UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSI0fl BEFORE THE ATOMIC SAFETY AND LICENSING BOARD t

In the Matter of HOUSTON LIGHTING & POWER COMPANY )

j

)

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Docket fio. 50-466 l

(Allens Creek Nuclear Generating )

l Station, Unit No.1)

)

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l AFFIDAVIT OF JOHN F. SCHARDT l

j State of California County of Santa Clara I, John F. Schardt, Senior Licensing Engineer, within the Safety and j

Licensing Operation of the General Electric Company, of lawful age, being duly sworn, upon my oath certify that the statements contained l

in the attached pages and accompanying exhibits are true and correct j

to the best of my knowledge and belief.

1 Executed at San Jose, California, l

July 49, 1980.

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/x Subscribed and sworn to before me this.29 day of July

, 1980.

Mr M2 NOTARY PUBLIC If4 AND FOR SAID COUNTY Af40 STATE l

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My commission expires b L v M e2 F

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175 Cwr mer Ave., $4m Jow, CA 95133 l

150 S0081901 03

UNITED STATES OF AMERICA

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NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of S

S HOUSTON LIGHTING & POWER S

COMPANY S

Docket No. 50-466 S

(Allens Creek Nuclear S

Generating Station, Unit S

No. 1)

S Affidavit of John F.

Schardt My name is John F.

Schardt.

I am employed at General Electric Company as a mechanical engineer.

I have l

been so employed for 10 years.

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

This affidavit addresses Mr. Doherty's Contention No. 15 which alleges that the computer code used by the General Electric Company to predict SCRAM reactivity following a Power Excursion Accident (PEA) is not conservative.-1/

i Mr.

l Doherty cites as a basis for this contention the Special Power i

Excursion Tests (SPERT) performed by the Idaho Nuclear Experimental i

Laboratories (in particular those test results reported as 1

1/

The PEA referred to in the contention, for which the 280 Ealories/ gram energy deposition is mentioned as a safety limit, is the rod drop accident.

This accident is not analyzed by the General Electric equivalent to the WIGLE code.

The computer code which is used for the Rod Drop accident accounts for neutron population changes in three space dimensions.

It has been shown to be conservative by recent studies performed at Brookhaven National Laboratory reported in "Effect of Thermal Hydraulic Feed-back on the BWR Rod Drop Accidenr," H.

S. Ching and D.

J.

Diamonds, authors, Transactions of the Amerr.can Nuclear Society, Vol. 33, November, 1979.

151

No. IN-1370) which allegedly show that a code (the WIGLE code) which produces results similar to those derived by General Electric is not conservative in calculating SCRAM reactivity.

I.

Calculating SCRAM Reactivitv SCRAM reactivity is a measure of the amount of.

negative reactivity produced by rapidly inserting the control rods, which shuts down the reactor, and is used as an input to the analysis of abnormal transients such as turbine trip, generator load rejection, and main steam isolation valve closure.

General Electric uses a one-dimensional time / space code to predice the value of SCRAM reactivity for various abnormal transients over core life.

The code models axial changes in the core which occur throughout the transient.

A cne-dimensional model has been shown to be appropriate by j

detailed reactor transient tests performed at Peach Bottom 2, l

where the data from the heavily instrumented core revealed the

+

l flux response to be one-dimensional.-2/

This code is I

i used to calculate SCRAM reactivity in the core as a function of time following the initiation of the abnormal transient.

)

i General Electric has been very conservative in its evaluation of SCRAM reactivity.

The values used for SCRAM reactivicy in calculating the severity of the abnormal l

transient are at least 20 percent less than those calculated by the one-dimensional space / time code.

In addition, the i

l 2/

L.

A. Carmichael and R. O.

Niemi, " Transient and Stability fests at Peach Bottom Atomic Power Station Unit No. 2 at End of i

Cycle 2," EPRI NP-564 (June, 1978)..

} 19 i

l

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control rods are assumed to move at their technical specification speeds, whereas plant measurements have demonstrated the actual performance to be much faster.

The overall conservatism employed in the transient calculations is demonstrated by comparirons with actual plant data generated in numerous plant start-ups, as reported in " Analytical Methods of Plant Transient Evaluation for the GE BWR," NECO-lO302, Vols. 1 and 2 (April, 1973).

II.

The SPERT Tests Mr. Doherty's reliance ca IM-1370 as a basis for disputing the conservatism in General Electric's one-dimensional time / space code is misplaced.

The SPERT project referred to in the contention tested the ability of the WIGLE code to calculate the time behavior of a pulse of neutrons deposited in a long thin multiplying assembly.

The experiment, performed in a test reactor which bears no rasemblance to a BWR core, showed that the WIGLE code underpredicted the response to a positive insertion of reactivity.

No control rods were inserted, t

so the test did not measure the effects of SCRAM reactivity.

l l

One could argue that since it underpredicted the response tc l

l positive reactivity insertion, it would also underpredict the l

negative reactivity response caused by control rod insertion, thus indicating the WIGLE code to be conservative for SCRAM reactivity.

However, it is my assessment that the SPERT.

153

experiment is so far removed from prototypical SWR SCRAM

~

conditions that it cannot be used for the assessment of the conservatism of the WIGLE code or General Electric's one-dimensional code for SCRAM calculations.

In summary, although General Electric's one-dimensional code may in some circumstances--for the specific purpose of t

predicting SCRAM reactivity-produce results similar to results

[

obtained from the WIGLE code, the criteria contained in the i

SPERT report (IN-1370) are irrelevant to SCRAM reactivity calculations, whether performed by WIGLE or General Electric's model. :

i l

154 1

i ATTACHMENT I PROFESSIONAL QUALIFICATIONS OF JOHN F. SCHARdT I

POSITION:

Senior Licensing Engineer EDUCATION:

B.S. - Mechanical Engineering,1968, Univ. of California, Davis M.S. - Mechanical Engineering,1970, Univ. of California, Davis General Electric Advanced Engineering Program,1972 ADDITIONAL BACKGROUND:

i Professional Engineer in Mechanical Engineering Completed numerous General Electric BWR Technical Courses i

I EXPERIENCE:

Program Engineer, General Electric Company.

1970 - 1972 Responsible for design, analysis, and testing of BWR ccmponents, particularly for seismic and flow-induced vibration.

1972 - 1974 Supervisor, Engineering Training Program, General Electric Co.

Responsible for supervising the hiring and training of new technical college graduates for General Electric's SWR Engineering Training Program.

i 1975 - 1976 Engineer, General Electric Company.

t Responsible for design and analysis of BWR fuel components.

Senior Engineer, General Electric Comeany.

1976 - 1979 Responsible for performing Flow-Induced Vibration (FIV) analyses and tests for BWR components.

In addition, managed a Department of Energy - fundad four year development program designed to further the state-of-the-art FIV technology for light water reactors.

1980 - Present - Senior Licensing Engineer, General El actric Company.

Responsible for achieving the resolution of safety and licensing concerns pertaining to BWR behavior during transient events, in-suring that the NRC regulations are correctly interpreted and satis-fted.

1 155

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