IR 05000269/1980003
| ML19323A418 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 02/25/1980 |
| From: | Economos N, Herdt A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML19323A410 | List: |
| References | |
| 50-269-80-03, 50-269-80-3, 50-270-80-02, 50-270-80-2, 50-287-80-02, IEB-79-13, IEB-79-17, NUDOCS 8004210199 | |
| Download: ML19323A418 (7) | |
Text
.
rm\\
v.
- pc.s'o,,
UNITED STATES
NUCLEAR REGULATORY COMMISSION
~
n g
e REGION ll
~#
101 MARIETTA ST., N.W., SUITE 3100 o
ATLANTA, GEORGIA 30303
Report Nos. 50-269/80-03, 50-270/80-02 and 50-287/80-02 Licensee: Duke Power Company 422 S. Church Street Charlotte, North Carolina 28242 Facility Name: Oconee Nuclear Station Docket Nos. 50-269, 50-270, and 50-287 License Nos. DPR-38, DPR-47, and DPR-55 Inspection at.0conee $en a,yuthCarolina x
,
,
Inspector:
~
J G -EMm P
,
N. Econ
's7,
/,
_ _ _Date Signed
"
Approved by:
I
$
MJ A. R. Herdt, Section Chief, RCES Branch Da1ie Si'gned SUMMARY
'
Inspection on January 24-17, and January 22-24, 1980 Areas Inspected This routine unannounced inspection involved 63.5 inspector-hours on site in the areas of IE Bulletins 79-13 and 79-17, Units 1, 2 and 3; Auxiliary feedwater nozzle thermal sleeve inspection and crack repair, CRD stator motor drop during maintenance, RPV flange 0-ring repair.
Results
.,
Of the areas inspected, no items of noncompliance or deviations were identfied.
,
,
l Boo 4e to /
___
_ _ _ _ _ _
_ _ _ _
.
.
.
.
DETAILS 1.
Persons Contacted Licensee Employees
- J. E. Smith, Station Manager
- J. M. Davis, Superintendent of Maintenance
- R. J. Brackett, Senior QA Engineer
- T. C. Mathews, Technical Specialist
- J. J. McCool, QA Surveillance Supervisor
- R. T. Bond, Technical Services Engineer
- L. V. Wilkie, Mechanical Maintenance Support Engineer B. Millsaps, Assistant Engineer E. Few, Technical Specialist
D. Holtsclaw, Mechanical Junior Engineer
,
l W. Gallman, Mechanical Junior Engineer D. Burges, Technical Support Engineer L. J. Jones, Maintenance Supervisor A. J. Hogge, Inservice Inspection QA R. L. Gill, Jr., Licensing C. W. Hendrix, Associate Engineer Other licensee employees contacted included construction craftsmen, technicians, and office personnel.
Other Organizations Babcock and Wilcox Construction Company (B&W)
C. E. Thompson, Level II UT Examiner
- B. W. Street, Resident Engineer
.
i R. Druin, Nuclear Power Generating Division s
'
NRC Resident Inspector F. Jape
- Attended exit interview 2.
Exit Interview The inspection scope and findings were summarized on January 17 and January 24, 1980, with those persons indicated in Paragraph I above.
The inspector identified the areas inspected which included welding, nondestruc-tive examinations and record review of: Auxiliary feedwater nozzle thermal sleeves for OTSG "A" and "B"; reactor vessel flange 0-ring groove and seal surface damage repairs ; stator motor drop incident record review; IE Bulletins 79-13 and 79-17.
The licensee concurred with the inspection findings.
... _..
.
.
-2-
.
3.
Licensee Action on Previous Inspection Findings (Closed) Unresolved Item 287/79-21-01, Reactor Vessel Vent Valve Exercise i
Test Results The inspectoc teviewed the licensee's investigation report concerning the exercising of the reactor internal vent valves, the limiting conditions of the test as defined in the ONS Technical Specification 4.20, B&W's calcula-tions and the steps taken to correct the error in the previous procedure.
4.
Unresolved Items
Unresolved items are matters about which more information is required to determine whether they are acceptable or may involve noncompliance or deviations. New unresolved items identified during this inspection are discussed in paragraphs 5. and 7.
5.
Accidental Drop of Stator Motor (S-55) During Maintenance (Unit 1)
On December 6, 1979, the licensee reported that in the course of performing maintenance work on the reactor vessel stators, one of the stator motors, core location K-9, which had been raised approximately fifteen feet above the operating level was improperly secured causing the motor to drop and come to rest on the motor tube or nozzle #4, on top of the reactor vessel head.
The licensee's investigation into this matter' included stress analysis calculations performed by B&W and documented on calculation sheet 32-1107021-00, surface and volumetric (UT) examinations.
The inspector discussed with the licensee's representative details of this incident which were documented as Station Investigation S-55 and reviewed related records and test results.
The inspector expressed concern over conditions and/or lack of administrative controls that permitted this incident Io occur and stated that existing procedures should be reviewed and possibly revised, as required, to preclude the recurrence of the problem.
In addition, the inspector stated that the nozzle to head weld should be reexamined by ultrasonics on the next scheduled refueling outage. This would be a precautionary measure against the presence
'
of a possible indication which may have been missed by the Ur examination but because of its exposure to opersting stress became more discernable.
The licensee agreed to study this matter further and report back to the inspector on a future inspection. The inspector stated that this matter would be identified as an unresolved item 269/80-03-02 "UT of nozzle to head weld".
Within the areas examined, no items of noncompliance or deviations were identified.
l
'
-*
_ _ _ _.
_
. - _
.
.
.
-3-
,
6.
Reactor Vessel Flange 0-Ring Groove Repair (Unit 1)
Improper installation of certain fastening clips used to secure the 0-ring seal to the reactor vessel flange surface caused some brinelling on the inner and outer reactor vessel flange sealing surfaces which required minor weld repair in order to restore the affected area to its original condition.
Also on the same surface area, at the Y-axis vessel location, a ortion of the 0-ring, approximately 10 to 12 inches long, slipped out of 4,s groove during replacement of the head during an earlier outage. The ;esulting interference, caused metal deformation in the annulus between the inner and outer o-ring grooves of the head and vessel flanges. The licensee's records indicated that on the head, the depth of the disturbed metal was approximately 1/16-inches while on the vessel 1/32-inches.
,
At the time of this inspection, repair work on these surfaces had been completed. The repair was performed under work request numbers 54378
-
" Repair Reactor Vessel Flange 0-Ring Groove" and 54162 " Repair Reactor Vessel Head and Vessel Flanges". Welding was performed in accordance with ASME,Section XI S75 and NB-4130, -4453 and -4640.
The inspector observed /
inspected the repaired surfaces and reviewed work packages, applicable field weld data sheets, welder and NDE personnel qualifications, material quality records and NSE records as applicable. Discussions with the licensee's representative disclosed that a change in clip design and a procedural revision that provides for proper clip installation should preclude the recurrence of this type probleme Within these areas no items of noncompliance or deviations were identified.
7.
Auxiliary Feedwater Nozzle Thermal Sleeve Cracking (Unit 1)
At the time of this inspectio'n the licensee was involved in the inspection and repair of the auxiliary feedwater nozzle thermal sleeves (sleeves) in both once through steam generators (OT$G) which had developed cracks in service. The cracks were located in the toe of the collar-to-sleeve weld and appeared to be fatigue related. The cracks extended circumferentially within the heat affected zone (HAZ) of the weld in question. Discussions with the licensee representative disclosed that these components have a history of cracking in this area. This has resulted in inspections and/or repairs to be performed during previous fuel outages. The table below provides a chronology of the sleeve repair history.
UNIT 1 1977 OTSG "A" Six (6) sleeves required repair.
OTSG "B" All seven (7) sleeves required repair.
!
O
.
.
.
-4-
.
,
UNIT 2 1976 All the sleeves in OTSG "A" and "B" were repaired One of the sleeves removed from OTSG "A",'was to be shipped to B&W in Lynchburg, Virginia, for failure analysis.' Subsequent discussions with I
Duke Power Company (DPCo) disclosed that B&W had proposed and the licensee
'
had accepted a repair program whereby a temper-bead welding technique used on the collar-to-sleeve weld and four wire type retainers were attached (welded) between the collar and the reducer portion of the sleeve. The purpose for the retainers was to capture the sleeve in case the collar-to-sleeve weld should fail again in service.
B&W has recommended this repair be performed in both OTSGs of Unit 1 before returning to power; this was completed on January 23, 1980. The licensee stated that B&W will redesign these sleeves and may have replacements available for installation on the next scheduled refueling outage.
Within these areas the inspector witnessed magnetic particle inspection of sleeves #2, #5 and #7 from OTSG
"B".
Sleeves #5 and #7 exhibited typical crack type indications which extended intermittently around the HAZ on both sides of the weld. On January 23 the inspector inspected sleeves #2, #5 and #7 from OTSG "A" that had the retainers attached as per procedure SPR-03-0764-01.
In addition, the inspector reviewed the applicable DPCo weld data sheet, L-202, welder qualifications, weld consumable and retainer wire quality documents, process control and related NDE procedures. While discussing this problem with the licensee the inspector requested and the licensee agreed to furnish RII with a report delineating the probable cause of
,
failure and the actions taken to preclude the recurrence of this failure on these components. This matter was identified as unresolved item 269/80-03-01,
!
" Auxiliary feedwater Thermal Sl'eeve Cracking".
!
8.
IE Bulletin 79-13, Cracking in Feedwater System Piping (Unit 1)
The radiographs of nozzle and pipe welds in the auxiliary feedwater system
that were taken in compliance with IEB 79-13 were reviewed on an earlier inspection and the findings were documented in RII 50-269/80-1. A misin-l
.
terpretation of code acceptance standards relative to allowable slag / porosity type indications for a given material thickness caused otherwise unacceptable welds to be evaluated as acceptable.
Because at the time of this disclosure film evaluation was still in progress the licensee agreed to reevaluate all the films in question.
The inspector reviewed the following radiographs to determine whether they were consistent with applicable Code, ASHE Section III (77), NC-5000 and to the 2T sensitivity level.
l
.
l-
,
i
'
i
-
.
.
.
-5-
.
OTSG "A" OTSG "B" Welds - 1 ELB Welds - 1 ELB 1 FLG 1 FLG 2 ELB 2 ELB 2 FLG 2 FLG 3 ELB 3 ELB 3 FLG 3 FLG S ELB 5 ELB 5 FLG 5 FLG 6 ELB 6 ELB 6 FLG 6 FLG 7 ELB 7 ELB 7 FLG 7 FLG
.
The film disclosed the following:
On the side of OSTG "A", all welds exhibited rejectable slag / porosity type indications with the exception of weld 3ELB which was acceptable; on the OTSG "B" side welds 2 FLG, 3 FLG, 5 ELG, 5 FLG, 7 ELG and 7 FLG were accept-able, the remaining welds had rejectable slag / porosity type indications.
'
The licensee has obtained the services of a consultant to review these aforementioned radiographs and issue a report in which the acceptability of these welds will be discussed.
.
Within the areas inspected no items of noncompliance or deviations were identified.
9.
IE Bulletin No. 79-17, Pipe Cracks in Stagnant Borated Water Systems at Power Plants (Unitn 1-3)
Surface and volumetric examination of selected welds for evidence of inter-granular stress corrosion cra'cking (ISCC) in stagnant borated water engineered safeguard pipe systems was being performed by Babcock & Wilcox (B&W) Company
.
under contract with DPCO.
I The ultrasonic examination procedure used for this program was developed
and demonstrated using weld specimens with SCC indications in the HAZ. The procedures used to perform surface and visual examinations were those used
!
.
for the inservice inspection program which comply with the ASME Code Sections V and XI (74S75). The procedures under discussion are listed below:
ISI-129 Rev. 1 Ultrasonic Examination (UT) of the Heat Affected Zone of Welds for SCC in Stainless Steel Piping
ISI-240 Rev. 3 Penet'r, ant Examination of Welds and Base Materials ISI-350 Rev. 8 Visual Examination of Welds and Surface Conditions The aforementiond procedures had been approved by B W's level III examiner
!
and were included in the Oconee Nuclear Station (ONS), ISI manual. Weld l
l l
l
. --
,
,..
6-
-
.
selection was made by the licensee's inservice inspection /QA Department.
Program coordination was provided by ONS mechanical maintenance while QA surveillance of field activities was provided by ONS, Quality Assurance.
WORK STATUS Unit 1:
Visual examination of inaccessible welds, as required by paragraph 2.(a) of IE Bulletin 79-17 R/1 was performed on December 11, 1979. Systems checked included reactor building spray (RBS) high pressure injection (HPI) decay heat removal (DC) and core flood.
Unit 2:
Surface and volumetric examination of accessible welds as per paragraph 2.(a) and (b) of the bulletin was in progress.
Surface examination (PT) of weld No. 52, low pressure injection system (LPI) ISO-22 part 2, was witnessed by the inspector. Weld selec-tion for NDE examination included 37 welds in LPI, 22 in HEI and 15 in RBS. Weld location, thickness and diameter were reviewed for compliance with bulletin requirements. UT examination was delayed for lack of weld 1 reparation and was scheduled to start during the weekend of January 26, 1980.
Unit 3:
Visual inspection of accessible welds was completed. Systems inspected included RBS, HPI and LPI. Records of these inspections were reviewed.for completeness and accuracy.
Certain welds, between 2-1/2" and 14" diameter in the HPI and LPI systems, were UT examined in accordance with paragraph 2.(b) of the original bulletin. A discussion'of this examination and findings is contained in 50-287/79-21.
Within these areas the inspector reviewed applicable procedures, drawings, material quality records and personnel qualifications for compliance with applicable procedures and standards.
Within the areas inspected no items of, noncompliance or deviations were identified.
.
-*.w,.4
-.