ML20052B596
| ML20052B596 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 04/21/1982 |
| From: | Oprea G HOUSTON LIGHTING & POWER CO. |
| To: | Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| REF-PT21-82 10CFR-050.55E, 10CFR-50.55E, ST-HL-AE-818, NUDOCS 8205030350 | |
| Download: ML20052B596 (2) | |
Text
E The Light Company n-i.,,, u#,i,,w-im.,s noo n-i m.m.m,,ooi onan April 24, 1982 ST-HL-AE-818 SFN: V-0530 Mr. John T. Collins Regional Administrator, Region IV h$@$bk.h!
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Dear Mr. Collins:
South Texas Project Units 1 & 2 3
Docket Nos. STN 50-498, STN 50-499 First Interim Report Concerning the Desian of the Residual Heat Removal System On March 26, 1982, Houston Lighting & Powe-Company (HL&P), pursuant to 10CFR50.55(e), notified your office of an item concerning the design of the Residual Heat Removal (RHR) System. The RHR heat exchangers are located at an elevation higher than the refueling water storage tank (RWST), which is the source of borated water for safety injection.
This configuration places the heat exchangers at the "high point" in the system, and therefore, subject to possible accumulation of noncondensible gases in the tube bundles when the system is not in operation.
The accumulation of noncondensible gases in the tube bundles could lead to a potential for water hamer when the low head safety injection (LHSI) pumps are started.
Brown & Root, Inc. (B&R) notified the NRC - Region IV office on March 26, 1982 that this item was potentially reportable pursuant to 10CFR21.
A copy of the B&R report concerning this item is attached and is intended to supplement our first interim report.
Bechtel Power Corporation (BPC) is currently evaluating this item and will provide HL&P with recomendations regarding the modifications which are required to preclude air entrapment in the RHR heat exchanger tube bundles.
The next report concerning this item will be submitted to your office by August 30, 1982.
If you should have any questions concerning this item, please contact Mr.
Michael E. Powell at (713) 877-3281.
e Very tru y yours, y
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Attachments e
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820503o350
Ilouston I.ighting & l'ower Company cc:
G. W. Oprea, Jr.
April 21, 1982 J. H. Goldberg ST-HL-AE-818 J..G. Dewease SFN: V-0530 J. D. Parsons Page 2 D. G. Barker C. G. Robertson R. A. Frazar J. W. Williams J. W. Briskin J. E. Geiger R. L. Ulrey S. M. Dew J. T. Collins (NRC)
D. E. Sells (NRC)
W. M. Hill, Jr.
(NRC)
M. D. Schwarz (Baker &Botts)
R. Gordon Gooch (Baker & Botts)
J. R. Newman (Lowenstein, Newman, Reis, & Axelrad)
STP RMS Director, Office of Inspection & Enforcement Nuclear Regulatory Commission Washington, D. C. 20555 R. L. Range /G. W. Muench Charles Bechhoafer, Esquire Central Power & Light Company Chaiman, Atomic Safety & Licensing Board n
P. O. Box 2121 U. S. Nuclear Regulatory Comission Corpus Christi, Texas 78403 Washington, D. C.
20555 H. L. Peterson/G. Pokorny Dr. James C. Lamb, III City of Austin 313 Woodhaven Road P. O. Box 1088 Chapel Hill, North Carolina 27514 Austin, Texas 78767 J. B. Poston/A. vonRosenberg Mr. Ernest E. Hill City Public Service Board Lawrence Livermore Laboratory P. O. Box 1771 University of California San Antonio, Texas 78296 P. O. Box 808, L-46 Livemore, California 94550 4
Brian E. Berwick, Esquire William S. Jordan, III Assistant Attorney General Harmon & Weiss for the State of Texas 1725 I Street, N. W.
P. O. Box 12548 Suite 506 Capitol Station Washington, D. C.
20006 Austin, Texas 78711 Lanny Sinkin Citizens for Equitable Utilities, Inc.
Citizens Concerned About Nuclear Power c/o Ms. Peggy Buchorn 5106 Casa Oro Route 1, Box 1684 San Antonio, Texas 78233 Brazoria, Texas 77422 Jay Gutierrez, Esquire Hearing Attorney Office of the Executive Legal Director U. S. Nuclear Regulatory Commission Washington, D. C.
20555 Revision Date 03-30-82
Brown ffRoot,Inc, eosi orrica sox Tarce, souston. Texas 77001 A Hathburton Company W.ll.em M. R.ce rY((
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Power Group (713) 676-3521 Mr. Richard C. DeYoung Office of Inspection and Enforcement U.S. Nuclear Regulatory Comission Washington, D.C. 20555
Dear Mr. DeYoung:
On March 26, 1982, Messrs. P. S. Jordan and H. L. Bell of Brown & Rcot, Inc. provided verbal notification to Mr. Cliff Hale of the Nuclear Regulatory Comission, Region IV Office of Inspection and Enforcement, of a problem in the design of the Residual Heat Removal / Safety Injection Systems (RHR/ SIS) for the South Texas Project. This situation was detennined by Brown & Root to be potentially reportable pursuant to 10CFR21 on March 26, 1982. This letter provides written notification of the potentially reportable condition in accordance with 10CFR21.
The potentially reportable condition involves design performed by Brown
& Root as the Engineer of the South Texas Project Electric Generating i
Station (STP) located near Bay City, Texas.
In September 1981, Brown
& Root was removed as the STF Engineer by Houston Lighting & Power Company (HL&P) and replaced by Bechtel Power Corporation (BPC). Since September 1981, Brown & Root and BPC have been involved in various STP transition activities, including transfer of responsibilities. As the result of this situation, HL&P recently elected to have BPC review responses to various FSAR questions which were prepared by Westinghouse Nuclear Energy Systems (WNES).
This review would have otherwise been performed by Brown & Root as a nonnal part of our responsibility as the STP Engineer.
The BPC review of WNES responses to FSAR Questions 211.26 and 211.39 identified an incoEsistency with actual RHR/ SIS design. BPC identified that the RHR heat exchangers are located at an elevation higher than the refueling water storage tank (RWST), the source of borated water for safety injection. This configuration makes the heat exchangers the "high point" in the system, and therefore, subject to possible accumula-tion of noncondensible gases in the tube bundles when the system is not in operation. Brown & Root discussed this condition with BPC at a re-cent " transition" meeting.
Both Units 1 and 2 of STP are each provided with three vertical, U-tube heat exchangers which serve a dual function of residual (decay) heat removal during nonnal plant shutdown and emergency core cooling during certain postulated accident events. The heat exchangers are located gjp h NC lN
Mr. Richard C. DeYoung March 30,1982
,M7M'N Page 2 within each Reactor Containment Building (RCB). The source of water for the emergency core cooling (safety injection) function is the re-fueling water storage tank (RWST) which is located within each Mechan-ical Auxiliary Building (MAB) of Units 1 and 2.
The top of RHR/ SIS heat exchanger tubes is approximately at elevation 64 feet and the top of the RWST is approximately at elevation 42 feet. The RWST is an atmospheric tank. During nomal plant operation, the RHR/ SIS piping and equipment are wetted but idle. Due to the difference in elevation between the RWST and the heat exchangers, system back-leakage may per-mit noncondensible gases to collect in the tube bundles of the heat exchangers while they are not in use. Should residual heat removal or safety injection be initiated with this condition existing, water 1
haniner or other undesirable effects may result.
The design of the RHR/ SIS (components and functional requirements) is the responsibility of WNES but system layout was performed by Brown &
Root. While the interTace requirements specified by W_NES were adequately considered by Brown & Root, they do not expressly address relative ele-vations of the subject components. The Brown & Root design as released for construction had been reviewed by W_NES and HL&P.
In Unit 1, the RHR/ SIS heat exchangers have been located in the RCB awaiting installation. Associated piping has not been installed. The RWST is stored in place in the MAB. The Unit 2 components have not been installed.
Two of the unique design features of STP (RESAR 41 Nuclear Steam Supply System), are the location of the RHR/ SIS heat exchangers within the RCB and the RWST within the MAB. This layout is not conraonly found in other Westinghouse or Pressurized Water Reactor designs. The STP design problem may, therefore, not be of generic significance.
An evaluation of the safety significance of the problem has not been perfomed. Because of the current status of Brown & Root with STP, we are unable to assure such an evaluation is perfomed and appropriate corrective action effected. The safety significance of this problem is judged to be not unlikely; therefore, Brown & Root has determined this condition to be potentially reportable pursuant to 10CFR21 pending completion of a safety evaluation.
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Mr. Richard C. DeYoung
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March 30, 1982
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Brown & Root has coordinated on this matter with BPC. We have been assured that BPC has the technical issue identified and that it will be evaluated and resolved consistent with BPC procedural requirements, Additionally, HL&P has been notified by Brown & Root of our concern and actions and WNES has been apprised of the condition. Any further comunication on and resolution of this matter should be expected from others.
Additional questions regarding this matter should be addressed to our Mr. Peter S. Jordan, ('713) 676-8205.
Very truly yours, BROWN &
MT, INC.
W. M. Ric Group Vice President cc:
Karl V. Seyfrit, Director Office of Inspection and Enforcement - Region IV U.S. Nuclear Regulatory Comission 611 nyan Plaza Drive, Suite 1000 Arlington, Texas 76102 D. G. Barker, Manager South Texas Project Electric Generating Station Houston Lighting & Power Company P. O. Box 1700 Houston, Texas 77001 R. L. Rogers, Manager Project Engineering Bechtel Power Corporation P. O. Box 2166 l
Houston, Texas 77001 l.
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