IR 05000275/1983020
| ML16340D509 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 06/17/1983 |
| From: | Hernandez G, Kirsch D, Mendonca M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML16340D506 | List: |
| References | |
| 50-275-83-20, NUDOCS 8306270350 | |
| Download: ML16340D509 (12) | |
Text
U.
S
~
NUCLEAR REGULATORY COHHISSION
REGION V
Report Nos. 50-275/83-20 Docket Nos. 50-275 License No. DPR-76 Licensee:
Pacific Gas and Electric Co an 77 Beale Street, Room 1435 San Francisco California 94106 Facility Name:
Diablo Can on Unit No.
Inspection at:
Diablo Canvon Site San Luis Obis o Count California Inspection conducted:
Na 23-June
1983 Inspectors:
G.
H. Hernan z, Reactor Inspector Mendonca, Resident Inspector D
ed Approved by: D.. irs, Chief, Reactor Projects Section No.
Da ed
~3ummaz:
~lns ection duzin the eziod of Na 23-Juno
1983 Re ozt No. 50-275/83-20 Areas Ins ected:
Unannounced inspection by a regional anf1 resident inspector of actions related to recent licensee identified items including indications of less than minimum wall thickness in certain areas of a Reactor Coolant Piping Loop weld; a leaking shop weld in the Component Cooling Water System; repair activities related to gouge and grinding marks in one area of Reactor Coolant, Piping Loop No. 1-3; and resolution of Unit 1 Reactor Vessel preservice inspection indications.
The inspection involved 67 inspection-hours by two NRC inspectors.
Results:
OE the areas examined, one item of noncompliance was identified in Lhe failure of thc li;censee Lo promptly notify the NRC of a potentially reportable condition in accordance with the technical specifications (paragraph 5).
8306270850 830624 PDR ADaCK 08000a75
I'
DETAIIS 1.
Individuals Contacted Pacific Gas and Electric Com anv (PGSZ)
"'W
+~R.
+" R
- R.
+"'W
- J, J D
- J.
-R.
+aR wD J J ~
ap.
"M.
"R T.
D.
A. Baymond, Assistant Manager for Nuclear Plant Operations C. Thornberry, Plant, Manager Patterson, Plant Superintendent D. Eztler, Project Superiatendent, General Construction B. Kaefer, Technical Assistant to Plant Manager A. Sexton, Supervisor of Operatioas B. Miklush, Supervisor of Maintenance V. Boots, Supervisor of Chemistry and Radiatioa Protection G. Tadaro, Security Supervisor T. Twiddy, Supervisor of Quality Assurance R. Bell, Quality Control Engineer, Geaeral Construction M. Gisclon, Power Plant. Engineer M. Conway, Personnel and General Services Supervisor N. Norem, Lead Startup Engineer M. Luckett, Regulatory Compliance Eagineer D. Smith, Senior Quality Control Engineer A. Gonzales, Quality Control Inspector b.
Bechtel Co oration (Bechtel)
+-J.
W. Shryock, Site Completion Manager D.
O. lkenery, NDE Level III Engineer c.
Pullman Power Products Co oration (Pullman)
H.
W. Karaer, Quality Assuraace/Quality Control Manager
+Denotes personnel attending the exit management meeting of May 27, 19&3.
"-Denotes personnel attending the exit management meeting of June 3, 1983.
2.
Licensee Action on Previous Ins ection Fiadin s (
en) Followu Item (50-275/83-17/05):
De radatioa of the Reactor Coolant S stem Pressure Bounda On May 3, 1983, the licensee submitted IER No.83-004 concerning the discovery oL gouges and marks in the reactor coolant system piping.
The marks and gouge were discovered on the discharge side oi the No.
Reactor Coolant Pump..Of the four blemishes discovered the most severe is a gouge approximately 0.150 inches deep by 2.0 inches long and 0.150 inches wide.
The licensee has completed an ASME Sectioa XI repair plaa which has been submitted to their eaginccriag department for review and
approval.
The licensee has determined that the gouges can be removed by grinding aad blendiag without violatioa of miaimum pipe wall thickness criteria.
The licensee's repair and inspection activities on this item will be examined during future inspections.
No items of aoacompliaace or deviations were identified.
3.
Unit 1 Preservice Ins ection (Baseline)
The Vestinghouse Preservice Inspection summary for Unit 1 is currently under review by the licensee.
Discussions with licensee personnel determined that the four indications requiring evaluation have beea resolved.
The four indicatioas are located oa the base material approximately four and one-half inches below the centerline of the flange-to-upper shell weld at vessel azimuths of approximately
,
115 2054 and 295~.
Evaluatioa of the indications suggest that they are the result of haadling lugs which may have been attached during vessel manufacture.
No items of noncompliance or deviatioas were identified.
4.
Com nnent Coolin Vater Veld Discre an On May 23, 1983 the licensee submitted IZR No.83-007 concerning a
discrepancy in a shop weLd in the Component Cooling Water System.
Licensee per"onnel observed that in the process of welding a reinforcement pad on a branch connection to the non-vital loop C of the Componeat Cooling Water System, water began leaking from the weld area.
The discrepancy was determined to be a flaw in the root pass of the shop weld joining the branch connection to the header.
The licensee indicated that repairs will be made using an approved ASME Section XZ repair program.
Ia the interim the branch connectioa has been cut out and sent to a materials laboratory to determine the failure mechanism.
As indicated ia LER No.83-007, the initial ultrasonic examinatioa of the discrepant weld and ten other similar welds indicated that the code required full penetration welds may aot have been made.
Kowever, when the branch connection with the discrepant weld was cut out, a full penetration weld was found.
The presence of the full penetration.
weld raises questions regarding the applicability of this type of NDE method for this weld configuration.
Examination of the weld detail for the discrepaat weld determined that the weld detail did not clearly specify what. type of weld was required.
Based on these findings the inspector considers that a document review of other similiar type branch connection weld packages would assure that the welds complied with code requirements.
In addition, the inconclusive results of the ultrasonic examination on the ten similiar type welds indicates that this type of nondestructive examination would not provide credible results.
The above expressed concerns and the Licensee's repair program and inspection activities will be examined during a future inspection.
(50-275/83-20/01)
5.
Violation of Minimum Wall Thickness on Reactor Coolant S stem Pi in On iiay 23, 1983, the licensee submitted LER No.83-006 describing four areas of Weld No. WIB"RC-2-17 that were found to be less than the minimum wall thickness specified by desiga.
Weld No. WIB-RC-2-17 is in Loop No.
2 of the cold leg between the reactor coolant pump aad the reactor vessel.
During this iaspectioa the inspector was informed that subserluenL examination by the licensee of t~enty additional welds (located inside the biological shield) identified two more welds with potentia1 minimum wall violations (Weld Nos.
2-19 and 4-17).
The licensee is performing additional confirmatory NDE examinations to verify the validity of the initial findings. If a minimum wall problem, is cnnfirrrred the licensee will document the discrepant welds on the same nonconformance report. rlocumenting Weld No. WIB-RC-2-17 ~
This weld is documented on Nonconformance Report No. DCI-83-QC-N024.
During examination of licensee activities related to this item the inspectors became aware of an rrpparent failure by the licensee to follow their nonconforming report procedure fo" the identification of discrepant conditions.
This failure resulted in a delay in notifying the NRC of a potentially reportable coadition in accordance with the provisoas of the Technical Specificatioas.
The chronology of events, from the initial discovery of the discrepant condition to the Hay 10, 1983 NRC notification.
is described as follows:
December 1982 the licensee formulated plans to examine Reactor Coolant System Piping welds.
December 7,
1982 " Weld No. W1B"RC-2-17 is measured with a NORTFC 131-9, ultrasonic tester.
December '3, 1982 " a wall thickness measurement report is submitted.
This repo rt describes potential minimum wall prob Lees with Weld, Nos.
VIB-RC-2-17 and MIB-RC-3-13.
This report is distributed to appropriate levels of plant managemeat including the plant manager, plant superiatendeat, and project. superintendent.
December l7, 1982 - a Nuclear Plant Problem Report (NPPR) is written oa Welds Nos.
WIB-RC-2-17 and WIB-RC-3-13.
January 7,
1983 - Meld Nos.
WIB-RC-2-1.7 and WIB-RC-3-13 are re-examined.
Weld No. 2-17 is confirmed below minimum wall and Weld No. 3-13 is found to be within design limits.
February 16, 1983 - Westinghouse attempts mechanical measurements from inside pipe, the results arc not conclusive but some low areas are detected.
March 28, 1983 - Weld No. WEB-RC-2-17 is examined again using a new ultrasonic tester (KBrJ'USL-38).
The weld is again confirmed below minimum wal April 1, 1983 - ISI/NDE weekly reports indicate that Weld No. WIB-RC-2-17 examined and confirmed below minimum wall.
April 13, 1983 - Westinghouse Ft.eld Deficiency Report is issued with a proposed disposition.
May 5, 1983 - a Nonconformance Report is written on Weld No.
WIP"RC-2-17.
May 6, 1983 - licensee requests that examinations oa Weld No.
WIB-RC-2"17 be repeated to conEizm aad determine to what extent the condition exists.
May 9, 1983 - Weld No. WIB-RC"2"17 is examiaed again using a KB/USL-38 ultrasonic tester and confirmed as being below minimum wall.
May 10, 1983 - NRC'nformed of minimum wall conditions for Weld No.
WIB"RC"2"17.
The inspectors noted t.hat.
CFR 50.36(c) specifies that Technical Specifications include items in the categories delinated therein.
Category No. 4, which is entitled "Design Features" states that,
"Design features to be included are those features of the facility such as material of construction and geometric arrangements which if altered oz modified would have a significant effect on safety..."
Section 5.4.1 of the Technical Specifications Eoz the Diablo Canyon Nuclear Power Plant Unit, No.
1 states that,
"The reactor coolant system is designed and shall be maintained...in. accordance with the" code requirements specified in Section 5.2 of the ESAR..."
Section 5.2.3 of the Diablo Caayon FSAR, states-in part that,
"The minimum wall thickness of the pipe and fittings are aot less than that calculated usiag ASA B31.1, Sectioa 1 formula of paragraph 122-.-".
The inspectors reviewed Westinghouse Equipment Specification Ho. G-6/6341, dated April 4, 1967, which describes the design and construction of the reactor coolant system piping.
Paragraph 3.2 of this specification requires that'he minimum wall thickenss shall not be less than that caLculated using ASA B31.1, Section f paragraph 122.
Calculations by the inspectors verified the minimum wall design requirements for the cold leg of the reactor coolant piping is 2.22 inches.
Southwest Fabricating Drawing Ho. 7524-F, Sheet 9 specifies the minimum wall for the RCS cold leg piping as 2.215 inches.
The inspectors further noted that Nuclear Plant Administrative Procedure No. C-12, "Indentification and Resolution oE. Problems and Noaconformances,"
states in part in paragraph C.l.a that,
"The Plant Manager and the plant depart. ment heads have been delegated the responsibility for determining whether a problem identified ia a Nuclear
Plant Problem Report is a aoncoaformance."
A "c.".co"forzance is defined in paragraph C. i.b. of t.'his procedure as a, Discrepancy or departure irom requirements in purchase specifications, drawings, approved practices, established Quality Assuraace polici " or procedures, oz NRC requlations which require resolution...and... i'eft uncorrected could have result<<d iu degradation or loss of integrity of the reactor coolant pre sure boundary."
Appendix A of the procedure provides examples to aid in determining whether a problem or potential problem is a nonconformance.
Paragraph E.l. of Appendix A to the procedure states that,
"A discrepancy or departure from requirements in design documents or activities shall be identified and documented as a nonconformance iE...It was identified after the design document had been approved and it was issued for use as a basis for further desiga."
The departure of Weld No. MIB"RC-2-17 from specified design requirements appears to fall into the category of a nonconformance.
Therefore, as the previously presented chronology of licensee actions indicate that by December 13, 1983 appropriate levels of plant management were informed of the discrepancy.
In addition, on December 17, 1982 a
Nuclear Plant. Problem Report No. DCI-82-QC-P0300 was written describing the discrepant condiLioa, though it was not reported at this time as a
condition requiring a nonconformance report. It appears that sufficient evidence was available *t this time to warrent issuance of a aoacoformance report. If a nonconformance had been written the Technical Review Group would have been required to review the discrepant, condition for reportabllity under the Technical Specifications.
Further, paragraph 6.9.1.12.i of the Technical Specifications requires that,
"Discovery during unit life of conditions aot specifically considered in the safety analysis report or technical specifications that require remedial action or corrective measures to prevent the existence or development of an unsafe condition," be reported within 24 hourh to the NRC.
Discussions with the Office of Nuclear Reactor Regulation (HRR),
~".andard Technical Specification Group indicate that corrective measures inc1udes engiaeering analysis.
It appears that the late documentation of the condition in the nonconformance reporting system contributed to the untimely reportiag of this problem to the NRC.
The failure of the licensee to comply with technical specificatioas and report the d'efective weld in a timely manner is considered an apparent
,item of noncompliaacc.
(50-275/83-20/02)
6.
Haaa cment Neetin 0'n May 27 and June 3,
1983, the inspectors met with licensee representatives denoted in paragraph I.
The scope of the inspection, the observations, and the findings of the inspectors were discussed.
The licensee acknowledged the inspectors concerns and the apparent item of noncompliance as described in this repor O.
% ~