ML20195C025
| ML20195C025 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde, 05000534  |
| Issue date: | 04/29/1986 |
| From: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | Kirsch D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| REF-PT21-86, REF-PT21-86-189-000 ANPP-36431-EEVB, DER-86-09, DER-86-9, PT21-86-189, PT21-86-189-000, NUDOCS 8605290636 | |
| Download: ML20195C025 (5) | |
Text
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t ti:CEIygg, H3c Arizona Nuclear Power ProjectES pq ;g g P o BO A 52034
- PHOENIX. ARl2ONA 85072-2034 bb April 29,1986nf$[$RY;-92.11 ANPP-36431-EEVB/
Corrected Copy U. S. Nuclear Regulatory Commission Region V 1450 Maria Lane - Suite 210 Walnut Creek, California 94596-5368 Attention: Mr. D. F. Kirsch, Acting Director Division of Reactor Safety and Projects Palo Verde Nuclear Generating Station (PVNGS)
Units 1, 2, 3 Docket Nos. 50/528, 529, 530
Subject:
Final Report - DER 86-09 A 50.55(e) and 10CFR21 Condition Relating to Post Accident Sampling System (PASS)
File: 86-006-216; 86-056-026; D.4.33.2
Reference:
(A) Telephone Conversation Between A. Hon and D. R. Larkin on February 26, 1986.
(Initial Reportability - DER 86-09)
(B) ANPP-35774, dated March 28, 1986. (Interim Report - DER 86-09)
Dear Sir:
Attached, is our final written report of the Subject Deficiency which has been determined to be Not Reportable under 10CFR50.55(e) and 10CFR21.
Very truly yours,
\\
Ch o
E. E. Van Brunt, Jr.
Executive Vice President Project Director EEVBJr/DRL/1df Id f/009/FURM-10 Attachments cc: See Page 2 8605290636 860429 I
PDR ADOCK 05000528 13 S
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m Corrected Copy ANPP-36431-EEVB/LAS/DRL-92.11 April 29, 1986 Mr. D. F. Kirsch Acting Director Page 2 cc:
J. M. Taylor, Director Office of Inspection and Enforcement t
U. S. Nuclear Regulatory Commission Washington, D. C. 20555 A. C. Gehr (4141)
R. P. Zimmerman (6295)
Records Center Institute of Nuclear Power Operations 1100 Circle 75 Parkway - Suite 1500 Atlanta, Gerogia 30339 Idf/001/CrbnCpy
c c
FINAL REPORT. DER 86-09 DEFICIENCY EVALUATION 50.55(e)
ARIZONA NUCLEAR POWER PROJECT (ANPP)
PVNGS UNITS 1, 2, 3 I.
DESCRIPTION OF DEFICIENCY In the gas sampling portion of the Post Accident Sampling System (PASS),
two (2) identical vacuum pumps (Thomas Industries, Inc. Model No.
2737CM390) that are piped parallel to each other draw a sample of the containment atmosphere through the sample conditioning equipment, the remote grab sample unit and then return the sample to containment.
, NUREG 0737 requires that within three (3) hours after the decision is mde to take samples following an accident, a containment atmosphere sample must be obtained and chemical and radiological analysis must be performed.
To satisfy this requirement the subject pumps rust be capable of providing a containment air sample, at the time the containment air pressure and temperature could be as high as 30 psig and 250 F, respectisely.
A confirmtory test (Ref. 1) was conducted to ascertain if the subject pumps could function as required.
This test showed that the pumps performed satisfactorily if their suction pressure was mintained at 1.0 poig.
However, it was discovered that above 10 psig the pump motor starts to drav excessive electrical power and trips the motor on therml overload.
As installed, the pumps would not be capable of drawing a containment air sample if the containment air pressure is 30 psig.
It is estimated that under postulated accident conditions the pumps would be inoperable for the first 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> of the accident.
EVALUATION After reviewing the test data and evaluating it with the vendor, it was believed that these vacuum pumps could operate against a 30 psig discharge pressure with lover suction pressure.
The confirmatory test set-up was changed to include a pressure regulator, that was installed immediately upstream at the inlet to the air pumps.
Test results with the regulator installed showed that when the pump inlet pressure vna reduced tn P.5 psig, the pumps were able to operate against a 30 poig simulated containment pressure at an air temperature of 250 F.
The pumps eventually stalled when the air temperature was reduced to 120 F since at this temperature the air is denser, causing the pumps to work harder.
The pressure regulator was reset so that the pumps inlet pressure was reduced to 1.0 psig so that the pumps operated satisfactorily at both 120 F and 250 F.
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If this condition were to remin uncorrected, the PASS vould not be in compliance with the FSAR which specified that the capability to sample containment air shall be in conformance with NUREG 0737.
How-ever, failure of the PASS to obtain a containment air sample during the first hours after a postulated accident is not a significant safety condition since the PASS is not required to either identify or mitigate the consequences of postulate accidents.
However, in the event of an accident, the containment atmosphere could be analyzed by use of existing radiation monitors and the post LOCA Hydrogen analyzers for core damage assessment.
Engineering decided to utilize the subject pumps based on a preliminary engineering evaluation of available alternatises.
The pump application was discussed with the supplier.
Verbal concurrence was given by the vendor that the pump was suitable for the described application.
Engineering's goal throughout the detailed design efforts was to ensure that all aspects of PASS vere within design basis.
The sample pumps were installed and tested under norml containment pressure and declared operable.
Confirmtory testing, under postulated post accident condi-tions, was then initiated.
When the initial confirmtory test results were unfavorable, the supplier was again contacted and the application van discussed in detail.
The vendor's reply was that the pumps should operate in the postulated post accident conditions, but would fail to start if the inlet pressure is greater than 15 psig.
Engineering, with the supplier's concurrence, decided to reduce the pump inlet pressure to a value suitable for continued pump operation.
With vendor participation, Engineering then retested the pumps and the results revealed that the pump inlet pressure regulation was suitable.
The root cause of the deficiency was a lack of complete understand-ing of the design parameters, by the vendor, for the selected equipment and failure to perform verification testing under all anticipated conditions.
To verify that similar design conditions do not exist in other aleas, all Control Systems identified in the Project Design Criteria vere reviewed.
No other comparable design condition exists in which air must be pumped out of a building and returned, where the building can be pressurized to 30 psig.
It has been determined that this is an isolated condition.
II.
ANALYSIS OF SAFETY IMPLICATIONS PASS is a nonsafety related system, whose operation is not necessary to assure the:
a)
Integrity of the reactor coolant boundary.
b) Capability to shut down the reactor and/or mintain it in a safe shutdown condition.
(
c c) Capability to prevent orfaltigate the consequences of accidents which cg.uld result in potential off-site CXposure.
Therefore, this condition is evaluated as Not Reportable under the requirements of 10CFR50.55(e) and Part 21 since, if left uncorrected, it would not represent a significant safety l
condition.
III.. CORRECTIVE ACTION Based upon the satisfactory rotest results with the regulator installed upstream of the pump, it has been decided to install a pressure regulator / pressure reducing valve upstream of the compressor, so that the compressor's inlet pressure is reduced to 1.0 psig or less regardless of the containment pressure.
The pressure regulator modification has been completed in Unit 2.
The testing of Unit 1 modification is in progress.
Installation of PASS in Unit 3 has not yet been completed. The pressure regulator modification will be installed during the installation of the Unit 3 PASS.
In addition, the vendor has been contacted and the pump's operational requirements and suitability have been documented.
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