ML20093D018
| ML20093D018 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 09/21/1984 |
| From: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | Bishop T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| ANPP-30535-TDS, DER-83-74, NUDOCS 8410110039 | |
| Download: ML20093D018 (8) | |
Text
-.
- I*'
L Arizona Public Service Company t
6) iy.
01 E'.
3
?I September 21, 1984 g
m Q
ANPP-30535-TDS/TRE g f.
N 2
tb ^
9 v>
fG -
U.N. Nuclear Regulatory Commission-Region =V
-Creekside Oaks Office Park 1450 Maria Lane - Suite 210 Walnut Creek, California 94596-5368 Attention:
Mr.' T. W. Bishop, Director
. Division of Resident Reactor Projects and Engineering Programs r
Subject:
Final Report - DER 83-74:
Relating To Undersized Welds In Unit 1~ Auxiliary Building Discovered During The NRC CAT Inspection.
File 84-019-026; D.4.33.2 Ref erence s (1) ANPP-28749, dated January 31, 1984 Dear Sir Attached.for your information is our written report of DER 84-74.
This report provides follow-up information given in Attachment D,
Part II, Response to Violations II.B.3 and II.B.4, transmitted in Reference (1).
Very truly yours,
(
CW w
E. E. Van' B runt, Jr.
APS Vice President Nuclear Production ANPP Project Director EEVB/TRB Attachment cc: See Page Two
'hO l
DO O
8
.ZE-M i l
r I
Mr. T; W. Bishop i.
~ DER 83-74 Page Two cc:
Richard DeYoug, Director
-Office of Inspection and Enforcement U. S. Nuclesr Regulatory Commiseion
. Washington, D. C.
20555 T; C. Woods, Jr.
D. B. Karner t
W. E. Ide
- D. B. Fasnacht A. C. Rogers L. A.. Sour.a D. E.. Fowler.
T. D. Shriver C. N. Russo J. Vorees J. R. Bynum J. M. Allen j
J. A. Brand A. C. Gehr W. J. Stubblefield
'W. C. Bingham R. L. Patterson R. W. Welcher H. D.. Foster D. R. Hawkinson L. E. Vorderbrueggen R.'P.
Zimmerman S. R. Frost L..Clyde M. Woods T. J. Bloom Records Center Institute of Nuclear Power Operations 1100 circle ~75 Parkway, suite 1500 Atlanta, CA-30339 L
t t
t
s FINAL REPORT - DER 83-74 DEFICIENCY EVALUATION 50.55(e)
ARIZONA PUBLIC SERVICE COMPANY ( APS)
PVNCS UNIT 1 I.
Description of Deficiency Durlog the September 1983 NRC inspection of Train A of the Safety Injection System, 12 pipe supports were found which did not meet the criteria of the design drawing and applicable tolerances allowed by Procedure WPP/QCI 201.1.
The supports had been verified acceptable during the period July 14, 1980 to September 15, 1982.
The welds and deficiencies are described in NRC Inspection Report No. 50-528/83-34, Pages V-5, 6 and 7.
Specific pipe support violations are identified on NCRs PA-7141, PA-7149, PA-7151, PA-7154, PA-7155, PA-7170, PA-7171, PA-7229, PA-7230 and PC-7238.
The majority of problems identified were related to the size and quality of welds which were performed by the craft and accepted by Quality Control.
In reviewing the violations, most of the problems are a result of uncicar pro-cedures for inspecting welds.
For example, along circumferential areas of piping, problems arise when a pipe stanchion or a pipe lug is prepared to fic up to a pipe.
The fitup of pipe spools and support stanchions leaves a gap between the inside and outside diameters of the stanchion.
Although the design drawing specified the pipe spool to support stanchion attactnent weld to be an all-around fillet weld, this attacluent weld in many cases was made by f1111ng in the gap between the spool and the stanchion and becomes equivalent to a partini penetration weld.
This type of weld has in all cases been shown to be structurally adequate for the design loads.
Another common problem detected on wolded piping a ttaclunent s such as support stanchions was the omission of the fillet weld cap on a full penetration veld required by the design drawing.
Fillet weld caps are normally specified on all support stanchions with f ull penetration attaclaent welds to provide a smooth stress path transition between the pipe spool and ths stanchion.
Ilowever, due to the size ratio between the pipe and the support stanchions used on this project, the majority of all stanchions do not actually require the fillet weld caps at the points of obtuse intersection.
Even though these cases do not cover all discrepancies found, they are an example of the types of occurrences observed. When designing pipe supports, certain criteria are used by Engi-
Mr. T. W. Bishop DER 83-7 4 '
Page Two neering which tend to establish a large f actor of safety in the assembly.
To meet stiffness requirement, deflection allowables are established.
By designing the assembly to meet these allow-ables, stresses in the individual members are kept significantly below the allowables established by code.
For small bore pip-ing, actual stresses tend to be not more than 20% of allowables while for large-bore piping, stresses are generally never more than 60% of allowables.
In addition, weld sizes are usually governed by code minimums and not strength requirements.
During subsequent reinspection of pipe supports on Train B of the Safety Injection System, Nonconformance Reports (NCRs)
PA-7319 to PA-7326 and PA-7329 to PA-7332 were initiated to document undersized and/or incomplete welds on hangers located in Unit 1 Auxilia ry Building.
These items were previously inspected and accepted by QC after co:ssitments noted in DER 79-10 which included revising cons truction WPP/QC1 201.1 to re quire a Bechtel visual inspection of previously completed vendor welds plus the usage of weld fillet gauges.
Since a number e f supports on safety-related systems were found to be " substandard" with regards to the design requirements, the project elected to implement a major and comprehensive rein-spection program.
The following types and categories of sup-ports and pipe racks were included in this reinspection programt A.
All ASME Nuclear Class 1 pipe supports.
B.
All ASHE Nuclear Class 2 and 3 pipe supports included in the Condensate Transfer and Storage
- System, the Essential Chilled Water System, the Essential Cooling Water System, the HVAC Containment Butiding, and the Con':ninment Hydrogen Control System.
C.
All pipe supports in the In-Service Inspection Program which includes the Auxiliary Feedwater System, the Chemical and Volume Control System, the Reactor Coolant System, thn Main l
Steam System, and the Safety injection and Shutdown Cooling System.
D.
All other safety-related pipe supports inspected and accepted by Construction QC prior to June 1980.
Mr. T. W. Bishop DER 8 F74 Page Three The reinspection program included 2199 pipe supports and pipe racks.
All inspections of the program were completed on December 16, 1983.
A total of 2,047 pipe supports and 104 pipe racks were inspected.
The remaining 48 pipe supports were deleted from the program due to inaccessibility.
All nonconforming conditions noted during the reinspection program were documented on NCRs PX-7370 and PA-7313.
These NCRs identify a total of 1,269 nonconforming conditions on 807 different pipe supports or pipe rack assemblies.
The majority of nonconforming conditions were concerning wolds.
A total of 925 (72.9%) of all conditions reported addressed weld quality, weld size and weld length / location deficiencies.
Weld quality includes the general quality of weld (example, weld splatter) and accounts for 93 (7.4%) of all deficiencies.
Weld size is the evaluation of all welds either undersize, oversize or cases where the size of weld is unclear on the applicable design documents.
This case accounts for all incomplete welds, short welds, intermittent spacing incorrect, missing welds and incorrect locations of welds and accounts for 267 (21%) of all deficiencies.
All weld deficiencies were-evaluated as not having an adverse affect for the reopective systems with tu following justifications:
(1) All linear indications which re sulted in code violations were removed.
(2) As stated previously, Engineering has enough conservatism to account for construction practices.
(3) of all the undernize welds which violate the AISC, AWS or ASME Code requirement, 872 were 1/16" undersize, 11% were 1/8" undersize, and the remaining 2% were noted as being 3/16" undersised.
The welds which were 3/16" undersized were on obtuse angles where accurate measurement s could not be made, or in' low stress areas where tlw minimum AISC weld size was not required f or strength.
The design of the subject pipe support welds have been qualified as described in Rechtel's H&QS Report CRS-020-02, which is included with DER 80-3.
The "as-built" calculations indicate that the designs a re sufficient to carry the project design loads.
The ref ore, the installed and as-designed pipe suppo rt s are acceptable without repair.
While the majority of the problems involved welds, the most nevere probicas found involved pipe support configuration and pipe support component deficiencies, pipe support configuration defleiencies include all f abrication problems, such as members which were distorted or missing, and accounts for 165 (13%) of all deficiencies.
Pipe support component def iciencies include trueness, correct installation, hardware being in place and in the right orientation.
This case accounts for 135 (10.6%) of d11 detficienctese
m_..
4 5.;
- 1_
l 3
-. Mr. T. W. Bishop _
1 DER : 83-74 LPage Four-The ' most ? severe ~ deficiencies identified by.the reinspection-u
_ program; : include-five. supports _ which-have undocumented'-
disassembly.='after final Constructionf QC. acceptance... These-include: hangers 1EC013H00E,1EC014H0Gi and 1EC061H00J 'which were f ound. with the high-strength bolts - removed; hanger 1EC015H00E-
- had a member completely; removed;, and hanger ISI220H007 which had y-one of. two snubbers disconnected (at done end.s These conditions-
~
of 0.2 percent and are
- represent - an overall failure rates evaluated as safety-significant..
1The. evaluation.of the reported hanger configuration : and
' component L deficiencies. also indicates that the _ adequacy of 41
. ith problems in -their categories - have. been pipe supports w
- f rendered -
indeterminate.;
The _ various problems include:
'(1) components skewed beyond manufacturers. tolerance, L
^
.(2) component pipe. clamp ~ bolt E loose,- (3) strut lock nut loose, (4) strut retainer - ring missing, (5) cotter pins missing-and (6)
.p various; jam nuts. missing.
In each of the above cases,' _ the -
missing locking. device will not. cause a failure of the support but could_ lead
-to=' component fallure.
Many cases involved documentation 'of field routed instrument air line : and conduit attached to pipe racks.. These loadsT are typically-very fema 11 x and 'had no impact on the' overall analysis.
In connection with this reinspection program, Quality Assurance :
conducted an overhew of the QC reinspection program on a random
. sample of - 99 pipe supports to assess inspection' ~ effectiveness.
This resulted in : rejection' of 7 pipe supports accepted._ by QC
.durits this-reinspection ' program for a 7-percent Terror rate.
p CAR S-83-56 was issued to QC to establish :cause and : obtain the
~
necessary' corrective ~ measures-to avoid' recurrence.:
All Jdeficiencies found' as-a result,of this overvie:5 program, however/were dispositioned :as "use-as-is."
II.;
Analysis of Safety Implications b
Engineerirg:
calculation _ analysis.
13-MC-ZZ-584 provides justification that non-conf orming pipe : support welds < would not.
g i -
degrade ~ the4 structural' integrity: of - the pipe - supports, and if left uncorrected, would not represent a significant'~ safety
~
condition.
The ;five supports, evaluated as safety significant U_ '
~
above, - have. been reassembled and restored to their original
[
-acceptable. condition.
U l?
4
~
=
)
.~
_i-
'W-_
2
,1 Mr. T. : W. ' Bishop
/
DER 83-74:
-Page Five III.-
Correetive - Action
' ' The' scope of the reinspection progran was ad' equate to determine the types,. severity,' and f requency of deficiencies which can be.
.- expected throughout each of the units.
' Additional inspections.
o of Quality Class "Q"
pipe supports in Unit cl.will be performed
.'to' address the safety-significant' findings of ' the initial sample reinspection program.'
' The additional inspection's ' will cover all supports ' f or-flanged spools designed to be removable and. all. sway strut, mechanical shock L suppressors, and ; spring cans. not included. in the initial
' inspections.- No additional - reinspection for weld size, length, or -quality. is l required based. upon the evaluated acceptance rate in the reinspection program.
Action to' preclude-recurr'ence in Units 2 and 3 is being initiated by implementing revised ' procedures for control of.
work performed - in Startup. coupled with the~ use of Bechtel Construction; procedures ' by; Startup to cover disassembly and
. reassembly as described in other parts of this response.
' In ' addition, inspection of randomly sampled pipe supports and hangers will be conducted in Units 2 and 3' to verify that the results of the Unit 1 inspection are applicable to Units 2 and 3.
The following training ; sessions including: specialized training by Bechtel's Material and - Quality Services (M&QS) on inspection
,.~
' techniques have ~ been conducted with QC and Field Engineering
. ersonnel:
[
p I
October-20, 1983 - Instruction of Pipe Support and. Welding l
QCE's by Bechtel M&QS on proper use~ of fillet : weld gauges and on visual weld inspection criteria.
October 27, ?l983 ' ! nstruction of' Pipe Support and Welding
~
I l7 QCE's and. Welding FE's by Bechtel M&QS on proper use of t -
M&QS weld gauge for skewed fillet welds.
December 7,.
1983 - Reinstruction of Pipe Support and Welding 'QCE's by PFQCE on weld reinspection acceptance criteria.
i L-December 14, 1983 - Reinstruction of Pipe Support and Welding QCE's by. Lead Welding QCE on pipe -support a
accept / reject criteria.
p.
.O
=
a Mr. T. V. ' 31 shop
. DER 83-7 4
-Page Six s.
- To preclude recurrence of Lidentified : conditions and improve and
~
direct.the -Quality Assurance activity. relative' to the installation.and 'QC acceptance of pipe supports and other key
~
construction activities,.ithe following Quality Assurance program
. improvements-are.being implemented.'
A.
A Corrective Action Reverification Program ha's. been:
established by Bechtel _Jobsite QA.
The purpose of this program ' is to '. reverify, ' the effectiveness-of previous
+
- corrective - actions taken for selected' quality ~ problems which:
Were serious. enough to have been reported ~ to the NRC (DERs)
' Have a history of recurrence
( t re nd s / audit / s urveillanc e CAR ' s)
May be generic (Bechtel Power Divisions CIDS computer program).
B.
The ' Field QA Surveillance ' Program L_will_.be upgraded to include a selectin sampling of _QC accepted installations on a monthly basis to continually assess effectiveness of the inspection program in vital areas of ' pipe' supports.
J NCRs have been dispositioned "Use-As-Is" f or ' pipe support welds and " REWORK" for deficiencies of the pipe hangers.
QA. verification of - corrective action taken by QC f or L
, CAR S-83-56 will be verified.upon closure of the
~
j.
applicable NCRs.
i
(
-Project ' Quality Program Manual, ~ Procedure
- 16. 0 ' -
- ~
Corrective Action - has been ~ revised to include the corrective action reverification program.
Project. Quality Program Manual, Procedure 18.6 -
has been-Project Quality Assurance-Surveillance revised to specifically-establish a monthly program -
f or an : overview of 4 previously accepted installations by QC.
i-l DER 83-74 final report closes corrective action f or NRC Audit L'
50/528,- Section II.B.3 and II.B.4.
ePW>>
ee 9TTM
-n
- gy'4
- ym+grW - y -sE v