ML13333A438
| ML13333A438 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 11/08/1979 |
| From: | Ziemann D Office of Nuclear Reactor Regulation |
| To: | James Drake Southern California Edison Co |
| References | |
| TASK-03-10.B, TASK-3-10.B, TASK-RR NUDOCS 7911270516 | |
| Download: ML13333A438 (6) | |
Text
DisIBUTION Local PDR ORB #2 Reading NRR Reading Docket No. 50-206 DGEisenhut RHVollmer DLZiemann HSmith PWO'Connor Mr. James H. Drake OEld Vice President I&E (3)
Southern California Edison Company DCrutchfield (2) 2244 Walnut Grove Avenue JRBuchanan Post Office Box 800 TERA Rosemead, California 91770 ACRS (16)
Dear Mr. Drake:
a 1979 RE:
COMPLETION OF SEP TOPIC III-IO.B -
SAN ONOFRE UNIT 1 Your letter dated October 5, 1979, indicated that you have examined our draft evaluation of the subject topic dated August 16, 1979. You suggested editorial or corrective changes to the assessment to make it more accurately reflect your facility design. We have incorporated your suggested modifi cations in the enclosed assessment. With these modifications our review of SEP Topic III-10.8 is complete and will be a basic input to the integrated assessment of your facility.
The subject assessment compares your facility design with the criteria currently used by the staff in licensing new facilities. This assessment may need to be re-examined if you modify your facility or if the criteria are changed before we complete our integrated assessment.
Sincerely, Orig in Dessina L.
Dennis L. Ziemann, Chief Operating Reactors Branch #2 Division of Operating Reactors Enclosure; Completed SEPd TopicM U194M DO-0.3R G ~
lCKET FILE COPY cc w/enclosure:
See next page DOR:ORB #2 D
DOR:ORB #2 O FFICE SURNME PWO'Connor:ah DM ch ield DLZiemann SRNATE
.... /..
DAE 1
/79
!/
/7 1
9/53
/79 NRC FORM 31,F 19-7;-- NR.Ct,.
- 5G VE M N
DNTN F
IE 1979-289-369
Mr. James H. Drake 2 -
November 8, 1979 cc w/enclosure:
Charles R. Kocher, Assistant General Counsel Southern California Edison Company Post Office Box 800 Rosemead, California 91770 David R. Pigott Samuel B. Casey Chickering & Gregory Three Embarcadero Center Twenty-Third Floor San Francisco, California 94111 Jack E. Thomas Harry B. Stoehr San Diego Gas & Electric Company P. 0. Box 1831 San Diego, California 92,112 U. S. Nuclear Regulatory Commission ATTN:
Robert J. Pate P. 0. Box 4167 San Clemente, California 92672 Mission Viejo Branch Library 24851 Chrisanta Drive Mission Viejo, California 92676 K M C, Inc.
ATTN:
Richard Schaffstall 1747 Pennsylvania Avenue, N. W.
Suite 1050 Washington, D. C. 20006
Complete -
November 8, 1979 SYSTEMATIC EVALUATION PROGRAM PLANT SYSTEMS/MATERIALS SAN ONOFRE NUCLEAR GENERATING STATION UNIT NO. 1 TOPIC 111-10.3 PUMP FLYWHEEL INTEGRITY The safety objective of this review is to assure that the integrity of the primary reactor coolant pump flywheel is maintained to prevent failure at speeds that might be reached under accident conditions and that preclude the generation of missiles.
Information for this assessment was obtained from Parts I and II of the Final Safety Analysis Report and the Technical Specifications for the San Onofre Unit No.
1 station, Westinghouse reports on Nondestructive Inservice Inspection of the San Onofre Unit No. 1 station, dated October, 1970, and January, 1972, and the Safety Evaluation prepared by the staff of the Materials Engineering Branch, DSS, dated June, 1975.
The basis for the review is to determine the degree of compliance with the recommendations of Regulatory Guide 1.14, "Reactor Coolant Pump Flywheel Integrity". This guide describes and recommends a method, acceptable to the NRC staff, of implementing General Design Criterion 4, "Environmental and Missile Design Bases", with regard to minimizing the potential for failure of the flywheels of the reactor coolant pump motor-.
There are two parts to the recommendation of Regulatory Guide 1.14.
The first part is related to the evaluation of materials of construction, design, fabrication, proof testing, and pre-service inspection of the pump flywheels for construction permit submittals docketed on or after January 1, 1976.
The second part is concerned with the evaluation of
.procedures used for the inservice inspection of pump flywheels for all plants after January 1, 1976.
The pertinent regulatory position for the inservice inspection of the reactor pump flywhe'els for the San Onofre Nuclear Generating Station Unit No. 1 is that the inservice inspection of each flywheel should be performed in~ compliance with the recommendations of Section of Regulatory Guide 1.14 as follows:
- a.
In-place volumetric examination of areas of higher stress concentration at approximately 3-year intervals;
- b.
Surface examination of all exposed surfaces and a complete volumetric examination at approximately 10-year intervals;
- c.
The examination procedures should comply with Subarticle IWA-2200 (ASME Section XI);
- d.
Acceptance criteria should be that the lowest critical s:eed is calculated to be twice the normal operating speed; and
-2
- e. Should the examination indicate an increase in flaw size greater than predicted for the service life, the results should be submitted to the regulatory staff for evaluation.
The integrity of the primary coolant pump flywheels was addressed by the licensee in the October, 1970, Nondestructive Inservice Inspection Report, the salient points of which are quoted below:
The primary coolant pump motor flywheels in Loops A, B, and C were ultrasonically examined for laminar-type indications. No significant indications were observed in flywheels "A" and "B".
Flywheel "C" had been previously examined ultrasonically by SwRI personnel in July of 1969, and a large lamination area was found at that time.
This area was again evaluated during the 1970 examination with special emphasis to determine if there were any changes in the previously detected defect area. There were indications of a possible extension or growth of the laminar flaw area by about 12 percent.
Shear wave tests during this examination indicated that the lamination did not have any significant components vertical to the plane of the flywheel.
The liquid penetrant examination of the bore of flywheel "C" indicated several large porosity holes and evidence of some cracks.
The defects were of an obvious fabrication nature and had not been previously noted as the bore was not examined during the 1969 inspection. Grinding to a depth of 0.25 in.
did not eliminate the cracks. The flywheel was replaced with a new one which was examined prior to installation using ultrasonics and liquid penetrants, and indicated no evidence of defects.
Information submitted by the licensee, including information on pump flywheel integrity and inservice inspection techniques, was reviewed and assesed by the Materials Engineering Branch, Division of Technical Review, in their Safety Evaluation dated June, 1975. The applicable portions of that Safety Evaluation are:
The original flywheels were made of ASTM 514, Grade B carbon steel.
In 1970 inservice examinations indicated several flaws in one flywheel.
This flywheel was subsequently replaced with a flywheel made of SA-533, Grade B, Class I material.
We have reviewed the applicant's inservice Inspection program to ensure flywheel integrity and conclude that -It confIorms witih the recommuendati ons of NRC Regul atory Gui de 1.14,
'Reactor Coolant Pump Integrity."
he orobability of a loss of pump flywheel integrity has been minimized by the use of suitable material, adequate design, and inservice inspection.
- ~use of adequate design and inserviCe inspections for the flywheels 0
reactor coolant pump motors in accordance with,he recommendations af Regulatory Guide 1.14 provides reasonable assurance (a) that he structural integrity of flywheels is adequate to withstand the forces
-3 imposed in the event of pump design overspeed transient without loss of function, and (b) that their integrity will be verified periodically in service to assure that the required level of soundness of the flywheel material is adequate to preclude failure.
.An addition to Table 4.7.1 of the Technical Specifications was proposed in the rep.ly to NRC Item 9.6.1 Response to Specific Items of Interest, Volume VI of the*Final Safety Analysis Report. The proposed addition was as follows:
- 1. Item G should be added to the "Specification" section as follows:
"G. The reactor coolant pumps shall be inspected in accordance with AEC Regulatory Guide 1.14 'Reactor Coolant Pump Flywheel Integrity.'"
- 2. Items 5, 6, and 7 should be added to the "Pump Pressure Boundary" section of Table 4.7.1, Outline of Inservice Inspection Program, San Onofre Nuclear Generating Station Unit 1, as follows:
Examination Components or Areas Scope and Frequency Category to be Examined Examination of Examination
- 5.
Pump Flywheel Volumetric Without removal of bore and key-the flywheel, all way accessible.areas at approximately 3-year intervals
- 6.
Pump Flywheel Surface Without removal of the flywheel, all accessible surface of the flywheel at approximately 10-year intervals
- 7.
Pump Flywheel Volumetric Without removal of the flywheel, 100%
of the flywheel during the inspection interval.
- Not required by Section XI of the Code, but specified by AEC Regulatory Guide 1.14."
- 3.
A new section, "Reactor Coolant Pump Flywheel," snould be added after the existing "Reactor Coolant to Primary Coiant System Piping Welds" section of Table 4.7.2, Inspection Schedule, as f:110ws:
-4 Planned Date Comoonets or Areas to be Insoected of Inspection "Reactor Coolant Pump Flywheel Pump A Flywheel bore and keyway 1976 Flywheel bore and keyway 1978 Flywheel bore and keyway 1982 Pump flywheel 1982 Pump B Flywheel bore and keyway
- 1976 Flywheel bore and keyway 1980 Pump flywheel 1980 Flywhelel bore and keyway 1984 Pump C Flywheel bore and keyway 1976 Flywheel bore and keyway 1980 Flywheel bore and keyway 1984 Pump flywheel 1984" It is intended that these proposed additions be submitted to the AEC in accordance with 10CFR50.59 as a formal request to revise the San Onofre Unit 1 technical specifications.
The proposed addition has not yet been added to the Technical Specification; however, it is being considered for addition in a future license amendment or incorporation into the Inservice Inspection Program in compliance with Paragraph (g) of 10CFR, Part
- 50.
We conclude from our review that the integrity of the flywheels on the primary coolant pumps will be adequately maintained by an Inservice Inspection Program in compliance with the recommendations of Regulatory Guide 1.14.
The reports of inservice inspections that have been performed on the San Onofre Nuclear Generating Station Unit No.
1 since October, 1970 show compliance with the guidelines set forth in the guide. However, it is recommended that additions be made to the Technical Specification or the Inservice Inspection Program to reflect compliance with the recommendations of Regulatory Guide 1.14.
These additions should follow those originally proposed by the licensee but not yet incorporated by the staff.