ML20214C878

Affidavit of RB Linderman Updating Info in Mar 1985 Affidavit Re Use of Probability Analyses to Determine Potential for Tornado Missiles Striking safety-related Structures.Certificate of Svc Encl.Related Correspondence

ML20214C878
Person / Time
Site:	South Texas
Issue date:	02/17/1986
From:	Linderman R BECHTEL GROUP, INC.
To:
Shared Package
ML20214C871	List: ML20214C867 ML20214C878
References
OL, NUDOCS 8602210309
Download: ML20214C878 (11)

Text

,

,i itELATED CORHESPONDENet

[ 00CMETED USNRC UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION W FEB 20 A10:21

, BEFORE THE ATOMIC SAFETY AND LICENSING g g ,

00CHEi % .._.. ,-

In the Matter of ) BRANii

)

HOUSTON LIGHTING & POWER ) Docket Nos. 50-498 OL COMPANY, ET AL. ) 50-499 OL

)

(South Texas Project, )

Units 1 and 2) )

AFFIDAVIT OF R. BRUCE LIPOERMAN My name is R. Bruce Linderman and I am an Engineering Specialist for the Western Power Division of the Bechtel Power Corporation. My business E

address is 12440 E. Imperial Highway, Norwalk, California. A statement of my '

background and qualifications was provided with my Affidavit in support of Applicants' March 12, 1985 Motion for Samary Disposition on CCANP Contention Four (March,1985 Affidavit). The purpose of this Affidavit is to update my March , 1985 Affidavit in accordance with the Board's January 29, 1936 Memorand s (Telephone Conference Call - January 28, 1986). <

In the Board's January 29, 1986 Memorandum, it requested that HL&P update the information in the March 1985 Affidavit regarding the use of probability analyses to determine the potential for tornado missiles striking safety-related structures or equipment at STP. The Board also posed the following question:

We have found that the fact that the IVC cubicle roof does not meet deterministic

! tornado criteria is acceptable because the probability of a serious release by this i

i D602210309 860214 POR ADOCK 05000498 G PDR

- . , - , , , . _ , , ,,v---- - , a ,- ---

--.---.---,e , , - - - . , - - - - . - , - - ~ . - - - . . _ .--

2 mechanism is low. We are now confronted with a similar argument with respect to certain MEAB HVAC louvers. Are two or three such failures to meet the deterministic requirements permissible, provided the sum of the probabilities does not exceed 1 x 10-7?

In my March,1985 Affidavit, I stated that " Category I structures at STP (with the exception of the Isolation Valve Cubicle (IVC) roof) are ...

designed to withstand a spectrum of missiles which might be generated by a DBT

[ design basis tornado] in accordance with Section 3.5.1.4. of the SRP" (March,1985 Affidavit at 9), and described the results of the analysis of the probability of a tornado (or hurricane) generated missile striking the IVC roof (id. at 10-11, Attachments II-IV). In addition to the IVC roof, certain Mechanical Electrical Auxiliary Building (MEAB) HVAC openings and diesel generator exhaast stack openings have not been designed to withstand the impact of tornado missiles.Y The MEAB HVAC openings are provided with hinged metal blades called dampers which are designed to close during a tornado. The dampers are not protected against the impact of tornado missiles since, in Bechtel's judgment, a missile striking the dampers would not be a credible event.

Nevertheless, a conservative analysis was performed of the probability of a tornado missile striking the MEAB HVAC dampers. That analysis (which is described in Attachment A to this Affidavit) resulted in a median probability of 2 x 10-10 per year. When combined with the probability of a tornado missile striking the IVC roof (also a median value of 2 x 10-10 per year), a median L value of 4 x 10-10 per year results, which is well below the NRC acceptance e

, .. -"/- Wile ~two doors in the EAB are not designed to withstand a tornado missile, other internal barriers protect safety-related equipment and components in the MEAB.

l 3

8 criterion of a median probability of 1 x 10-7 per year. Attachment A at 2-4.

It is important to note, however, that the acceptance criterion represents the probability of a release of radioactivity in excess of 10 C.F.R. Part 100 limits and that the probability of such a release resulting from a tornado missile striking the HVAC dampers or IVC roof is even lower than 4 x 10-10 ,

Attachment A at 3-4.

A portion of the diesel generator exhaust stacks is external to the diesel generator building. This portion is not designed to withstand the impact of a tornado missile, but will not jeopardize plant safety even if struck by a tornado missile. In particular, the exposed portion of the stacks has been designed such that it will not cause blockage or obstruction of the stack openings in a sufficient amount to affect the functioning of the diesel generators. The potential effect of a missile entering directly into the stack opening had not been specifically analyzed because it appeared to be an incredible event.

Recently, the NRC Staff requested that HL&P provide additio7al information regarding the probability or potential of such an event. Bechtel s

analyzed the probability of a tornado missile striking the stacks or entering the stack openings and calculated a median value of 1.2 x 10-12 er year. The median probability of a tornado missile entering the stack openings, or striking the IVC roof or MEA 8 HVAC dampers is approximately 4 x 10-10 per year. Attachment A at 2.

The probability of a hurricane-generated missile striking any of these targets is a median value of approximately 2 x 10-10 per year. The median probability of a tornado or rarricane missile striking any.of these tnrgets is

0-4 approximately 6 x 10-10 per year, still well below NRC acceptance criteria.

d at 3.

Id. Again, the probability of a radioactive release in excess of Part 100 limits resulting from any of these events is even lower. Id_. at 3-4.

I have reviewed Attachment A to this Affidavit as well as various design documents and drawings. That review indicates that no physical ,

barriers are necessary to protect the IVC roof, EAB HVAC dampers, or diesel generator exhaust stack openings from tornado and hurricane generated missiles. As Attachment A indicates, the probability analyses supporting that conclusion (including the summation of the probabilities of missiles striking the individual targets) are conservative and consistent with applicable NRC requirements and guidance. Since the sum of the probabilities of a missile striking these portions of the plant is well below NRC acceptance criteria, the conclusions stated in my March,1985 Affidavit remain valid.

State of Texas )

County of Harris )ss.

I, R. Bruce Linderman, Engineering Specialist, Western Power Division, Bechtel Power Corporation, of lawful age, being first duly sworn, .Upon my oath certify that I have reviewed and am thoroughly familiar with the statements contained herein and that they are true and correct to the best of my knowledge and belief.

$~

Subscribed and sworn to befqjr me this /7elday of th , 1986.

d m b.

Notdry Public V l

l My Commission Expires:

Wahr

Attachment A SOUTH TEXAS PROJECT PROBABILISTIC EVALUATION OF TORNADO AND HURRICAtE-GENERATED MISSILE HAZARD TO SAFETY-RELATED STRUCTURES AND CO N NTS AT SOUTH TEXAS PROJECT UNITS 1 & 2 (Revision 0) 14926-001 l

J RELIABILITY AND RISK ASSESSMENT GROUP BECHTEL POWER CORPORATION WESTERN POWER DIVISION

-- . , _ _ _ . - - - . _7,

I. I_NT,RODUCTION Studies have been performed using probability analyses to evaluate the probability of tornado and hurricane-generated missiles striking portions of Category I structures at the South Texas Project that are not designed to

, withstand the impacts of such missiles. Studies quantitatively assessing the probability of tornado and hurricane missiles striking the isolation valve cubicle (IVC) roof (References 1 and 2) were prepared (and submitted to the STP Atomic Safety and Licensing Board on March 12, 1985). The median (50th percentile) IVC strike probabilities were conservatively calculated to be 2 x 10-10 per year and 1.2 x 10-10 per year for tornado and hurricane-generated missiles, respectively.

This report summarizes the results of additional analyses performed to evaluate the incremental risk of tornado and hurricane-generated missiles striking other targets at the South Texas Project that are not protected against missiles. These targets are certain HVAC dampers in the Mechanical Electrical Auxiliary Building (MEAB), and the diesel generator exhaust stack openings. Probabilities for the individual targets are then combined to derive the total annual probability that any of these targets will be struck 1

by a tornado or hurricane-generated missile. No attempt is made to calculate whether missiles would impact and damage safety-related equipment nor is the potential consequence of such an event evaluated. Instead, for these analyses it has been conservatively assumed that a missile strike will result in damage to the targets and that such damage will result in releases in excess of Part 100 limits.

. 2 II. GENERAL APPROACH The methodology used to determine the probability of tornado and hurricane-generated missiles entering the top of the IVC was described in References 1 and 2, and was utilized in the tornado analysis of the MEAB HVAC dampers as well. The results of the probability calculations for the IVC roof were utilized to evaluate the probability of a tornado missile striking the diesel generator exhaust stack openings with a correlation using appropriate target specific parameters (target area and target elevation). A separate evaluation for hurricane missile strikes is also presented. In addition, the cumulative risk of a missile striking any one of multiple targets is conservatively obtained by summing the probabilities for the individual targets, consistent with the mathematics of probability.

III. PROBABILITY OF TORNADO MISSILE STRIKES TO THE MEAB HVAC DAMPERS Ato DIESEL GENERATOR EXHAUSTS The median annual probability of a tornado missile strike was calculated to be 2 x 10-10 per year for the EAS HVAC dampers and 1.2 x 10-12 per year for the diesel generator exhaust openings. The total annual probability of a tornado missile strike to any of the combined targets at STP (IVC roof, MEAB HVAC dampers and diesel generator exhausts) is the sum of the individual probabilities; i.e., 2 x 10-10 + 2 x 10-10 + 1.2 x 10-12, or approximately 4 x 10-10 per year.

D 3

t IV. PROBABILITY OF HURRICANE MISSILE STRIKES TO THE MEAB HVAC DAMPERS APO DIESEL GENERATOR EXHAUSTS As discussed in Reference 2, the median annual probability of a hurricane missile striking the IVC roof was calculated to be 1.2 x 10-10 per year. The methodology for calculating the strike probabilities resulting from hurricane and tornado-generated missiles is essentially the same. Therefore, once the total probability of a tornado-generated missile (PT ) striking the IVC roof, EAB HVAC dampers and diesel generator exhaust openings is known, the probability of a hurricane-generated missile (PH) striking these same targets can be determined on the basis of the following equation:

PT (all targets) _ PH (all targets)

PT (IVC) PHTIVC)

Based on this relationship, the total annual probability of a hurricane-generated missile striking either the IVC roof, EAB HVAC damrers, or diesel generator exhaust openings is about 2 x 10-10 per year.

V. CONCLUSI_0N The results of this analysis indicate that the median annual probability of a tornado or hurricane-generated missile striking the IVC roof, MEAB HVAC dampers, or diesel generator exhaust openings at the South Texas Project is approximately 6 x 10-10 per year (4 x 10-10 er year for tornado missiles plus 2 x 10-10 per year for hurricane missiles). The calculated probability of

. A such a missile resulting in a release of radioactivity in excess of 10 C.F.R. Part 100 guidelines will be even smaller. Therefore, both the probability of a missile strike and the probability of a resulting release are very small compared to the NRC activity release acceptance criteria of 10- to 10-6 per year. The probability analyses described above (including the sumation of the probabilities of missiles striking the individual targets) are conservative and consistent with applicable NRC requirements and guidance.

VI. REFERENCES

1. South Texas Project Probabilistic Evaluation of Tornado Missile Hazard to the Containment Isolation Valve Compartment Equipment, 14926-001, Risk / Reliability Group Los Angeles Power Division, Bechtel Power Corporation (August, 1983).

2. South Texas Project Probabilistic Evaluation of Hurricane -

Generated Missile Hazard to the Containment Isolation Valve Compartment Equipment, 14926-001, Risk / Reliability Group Los Angeles Power Division, Bechtel Power Corporation (Revision 1, November 1983).

r J' "'mo c0Aprunm ,,

UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION 00}{C BEFORE THE ATOMIC SAFETY AND LICENSING BOARD 16 HB 20 #0:21 In the Matter of )

ICE Of :.n n t .,w -

) "

HOUSTON LIGHTING & POWER ) Docket Nos. 50 bhkkhch COMPANY,-ET AL. ) 50-499 OL

)

(South Texas Project, Units 1 )

and 2) )

CERTIFICATE OF SERVICE I hereby certify that copies of the " Affidavit of Jerrold G. Dewease On The Progress of HL&P's Preparations for Operation Of STP Since 1982" and the " Affidavit of R. Bruce Linderman" have been served on the following indivi-duals and entities by deposit in the United States mail, first class, postage prepaid, or by arranging for delivery as indicated by asterisk, on this 18th day of February 1986.

Charles Bechhoefer, Esq.* Brian Berwick, Esq.

Chairman, Administrative Judge Assistant Attorney General Atomic Safety and Licensing For the State of Texas Board Panel Environmental Protection U.S. Nuclear Regulatory Division Commission P.O. Box 12548, Cupitol Washington, D.C. 20553 Station Austin, TX 78711 Dr. James C. Lamb, III' ,

Administrative Judge " Kim Eastman, Co-coordinator 313 Woodhaven Road Barbara A. Miller Chapel Hill, NC 27514 Pat Coy Citizens Concerned About Nuclear Frederick J. Shon* Power Administrative Judge 5106 Casa Oro U.S. Nuclear Regulatory San Antonio, TX 78233 Commission Washington, D.C. 20555 Lanny Alan Sinkin*

1324 North Capitol Street Mrs. Peggy Buchorn Washington, D.C. 20002 Executive Director Citizens for Equitable Ray Goldstein, Esq.

Utilities, Inc. Gray, Allison & Becker Route 1, Box 1684 1001 Vaughn Building Brazoria, TX 77422 807 Brazos Austin, TX 78701-2553

r-O Oreste Russ Pirfo, Esq.*

Robert G. Perlis, Esq.

Office of the Executive Legal Director U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Atomic Safety and Licensing Board U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Atomic Safety and Licensing Appeal Board U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Docketing and Service Section Office of the Secretary U.S. Nuclear Regulatory Commission Washington, D.C. 20555

'M M

• By Messenger 1

1

.-g - --

, . . . -n----, , , . , , ,,.,, -. . , . - - - .