ML20063C931
| ML20063C931 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 08/19/1982 |
| From: | Oprea G HOUSTON LIGHTING & POWER CO. |
| To: | Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, ST-HL-AE-869, NUDOCS 8208270423 | |
| Download: ML20063C931 (4) | |
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i The Light comPmY iie s'ee 'ix ti"a & re cr e o. nex ivoo >i"es'e". Tex s 77ooi (7's> 228-92i>
a August 19, 1982 ST-HL-AE-869 File Number: G12.123 SFN: V-0530 Mr. John T. Collins G
Regional Administrator, Region IV i
Nuclear Regulatory Commission ll 288 0 2 DR1
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t 611 Ryan P1aza Dr., Suite 1000 d
i Arlington, Texas 76012 11
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South Texas Project Units 1 & 2 Docket Nos. STN 50-498, STN 50-499 Final Report Concerning The Classfication of the Leak Detection System in the SIS / CSS Pump Cubicles On July 1,1982, pursuant to 10CFR50.55(e), Houston Lighting & Power Company notified your office of an item concerning the classification of the leak detection system in the Safety Injection System (SIS)/ Containment Spray System (CSS) pump cubicles. Attached is the Final Report regarding that matte r.
If you should have any questions, please contact Mr. M. E. Powell at (713)877-3281.
Very tr - syours,
J
/A 2_,
pfb Exe ive e President SSR/mg Attachment
,L' N', h 8208270423 820819 PDR ADOCK 05000498 S
PDR i
flouston Lighting & Power Company cc:
G. W. Oprea, Jr.
August 19, 1982 J. H. Goldberg ST-HL-AE-869 J. G. Dewease File Number: G12.123 J. D. Parsons SFN: V-0530 D. G. Barker Page 2 C. G. Robertson R. A. Frazar J. W. Williams R. J. Maroni J. E. Geiger R. L. Ul rey 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 G. W. Muench/R. L. Range Charles Bechhoefer, Esquire Central Power & Light Company Chairman, Atomic Safety & Licensing Board P. O. Box 2121 U. S. Nuclear Regulatory Commission 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 Livennore Laboratory P. O. Box 1771 University of California San Antonio, Texas 78296 P. O. Box 808, L-46 Livermore, California 94550 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 l
Office of the Executive Legal Director U. S. Nuclear Regulatory Commission Washington, D. C.
20555 Revision Date 08-09-82 l
FINAL REPORT ON CLASSIFICATION OF THE LEAK DETECTION SYSTEM IN THE SIS / CSS PUMP CUBICLES I.
Summary of Incident On July 1, 1982 HL&P identified to the NRC under the provisions of 10CFR50.55(e) that a potentially reportable condition exists with respect to detection of flooding in the SIS / CSS pump cubicles. An interim report was provided on July 29, 1982 (ST-HL-AE-859).
Bechtel review of the leak detection system during the system work package effort identified the potential for a passive failure in piping within one SIS / CSS pump cubicle to flood the adjacent SIS / CSS pump cubicles causing a loss of all three trains.
This final evaluation concludes that flooding of all three trains could occur without indication to the operator of the flooding. As corrective action, design features will be added to preclude the flooding of all three SIS / CSS pump cubicles.
II.
Description of the Incident HL&P was notified by BPC that a potentially reportable condition existed with respect to detection of flooding in the SIS / CSS pump cubicles. The condition was identified in the course of the review of the system work package EN-613 Radioactive Vents and Drains.
The condition involves a passive failure in moderate energy piping or the postulated passive failure of a pump seal in the SIS / CSS pumps.
If a passive failure occurs within an SIS / CSS pump cubicle, the affected cubicle could flood, then overflow to the corridor area, and then flood back into the other two redundant SIS / CSS cubicles. The following define the event that may result in a loss of ECCS capability:
A.
Passive failure of moderate energy piping or SIS pump seal during ECCS recirculation is assumed to occur.
B.
FSAR Section 3.6.1.2.3.3 indicates that there is safety related instrumentation in the pump cubicles to detect flooding.
C.
Contrary to this, both the pump cubicle sump level switches and the pump cubicle radiation monitors are non-IE Instrument Class IC-2*.
Additionally, it is indeterminate whether radiation monitors will be able to discriminate between:
(1) a high source term fluid in the ECCS during recirculation without leakage or (2) leakage from this system with lower source terms.
Furthermore, radiation monitors will not detect cooling water leaks.
D.
SIS / CSS pump cubicles do not have watertight doors to prevent inflow or outflow of water from corridors.
I
- Instruments are not procured at this time.
IC-2 is defined as assuring that structural integrity of the instrumentation is maintained after an SSE.
III. Analysis of Safe _ty Implications A review of the piping in the SIS / CSS pump cubicles indicates a break and the pump seal failure (50gpm) should be postulated in the analysis. Preliminary analyses show that the pipe break would result in flow rates of approximately 100 gpm.
These flow rates would result in the following minimum times to flood all three trains of ECCE pumps:
Flow Rate Time: Hours (Days)
Description 50 gpm 92.9 (3.9)
Pump Seal Failure 100 gpm 46.4 (1.9)
ECW line to room coolers The ECW line break and pump seal failures would not be detected by system instrumentation.
In addition, credit may not be allowed fcr reliance on operator action (visual observance of the pump cubicle area). Thus there would be no means of informing the operator that a leak was occurring.
Therefore, the safety implication is the loss of all three trains of SIS / CSS following a LOCA.
IV.
Recurrence Control A special recurrence control program is not considered necessary because this is the only situation where level indication was relied upon to mitigate against leakage of post-LOCA recirculation fluids outside containment.
Flooding analyses due to high and moderate energy line breaks are required in all safety related areas. This hazards evaluation is undertaken as part of the Systems Interaction Design Reviews which are conducted as part of Bechtel's normal design process.
V.
Corrective Action The corrective action will be to add design features to preclude the effects of a pipe break or seal failure from flooding all three trains of the SIS / CSS pump cubicles. This will be accomplished by providing safety grade instrumentation to detect leakage or by performing structural modifications to preclude flooding all three SIS / CSS pump cubicles. The design features j
selected will be documented in an FSAR amendment.
.