ML20210Q212
| ML20210Q212 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| 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-PT21-86-174-000 ANPP-36431-EEVB, DER-86-09, DER-86-9, PT21-86-174, PT21-86-174-000, NUDOCS 8605130645 | |
| Download: ML20210Q212 (5) | |
Text
_
o*g.
A diECE;vro
!3c Arizona Nuclear Power Project IS S u. - -
D 03 P.O. BOX 52034 o PHOENIX ARIZONA 85072-2034 April 29, 1986 ANPP-36431-E EVB / LAS /D$iffa92'.31;[r U. S. Unclear Regulatory Commission Region V 1450 Maria Lane - Suite 210 Walnut Creek, California 94596-5368 Attention:
Mr. D. F. Kirsch, Acting Director l
Division of Reactor Safety and Projects i
Palo Verde Nuclear Generating Station (PVNGS)
Units 1, 2, 3 Docket Nos. 50-528, 529, 530 i
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.
sA) 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, q tLL E. E. Van Brunt, Jr.
Executive Vice President Project Director EEVBJr/DRL/pgk Attachments cc: See Page 2 0605130645 860429 PDR ADOCK 05000528 S
PDR g
l g
ZE.19
e' ANPP-36431-EEVB/LAS/DRL-92.11 April 29, 1986 DE 86 FINAL REPORT Mr. D. F. Kirsch Acting Director j
Page 2 cc:
J. M. Taylor, Director Office of Inspection and Enforcement U. s. Nuc1 car 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, Georgia 30339 l
l l
l
o' 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 equipnent, the remote grab sample unit and then return the sample to containment.
NUREG 0737 requires that within three (3) hours after the decision is made 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 tha anhjaot pmnp9 nmt 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, respectively.
l A confirmatory 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 maintained i
l at 1.0 psig.
However, it was discovered that above 10 psig the pump l
motor starts to drav excessive electrical power and trips the motor I
on thermal overload.
As installed, the pumps would not be capable of drawing a containment air sample if the containment air pressure l
11 30 psig.
It is estimated that under postulated accident conditions the pumps vould 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 love'r 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 was reduced to 2.5 psig, the pumps were able to operate against a 30 psig 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.
l
s' If this condition were to remain uncorrected, the PASS would not be in compliance with the FSAR which specified that the capability to sample containment air shall be in' conformance with NUREG 0737.. Hov-ever, failure of the PASS to obtain a contain&ent 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 enalyzed 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 alternatives.
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 basin.
The samplo pumps were installed and tested under normal containment pressure and declared operable.
Confirmatory testing, under postulated post accident condi-tions, was then initiated.
When the initial confirmatory test results were unfavorable, the supplier was again contacted and the application was 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 resulta j
revealed that the pump inlet pressure regulation was suitable.
l The root cause of the deficiency was a lack of complete understand-l ing of the design parameters, by the vendor, for the selected equipnent and failure to perform verification testing under all anticipated conditions.
To verify that similar design conditions do not exist in other areas, 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 determinea that this is an isolated condition.
II.
ANALYSIS OF SAFETY IMPLICATIONS l
PASS is a nonsafety related system, whose operation is not necessary to assure the:
a) Integrity of the reactor coolant boundary.
l b) Capability to shut down the reactor and/or maintain it in a safe l
shutdown condition.
c s
'c c) Capability to prevent or mitigate the consequences'of accidents which could result in potential off-site -
exposure.-
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 condition.
- <o III. CORRECTIVE ACTION Based upon the. satisfactory retest.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.
'l l
-