ML20101Q452
| ML20101Q452 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 12/18/1984 |
| From: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | Kirsch D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| ANPP-31527-TDS, DER-84-53, NUDOCS 8501070627 | |
| Download: ML20101Q452 (9) | |
Text
-
i' - l'!ED Arizona NuclearPowerProject a rg a
'i g ;7 P.O. box 52034 e PHOENIX. ARIZONA 85072-2034 E,t " ',',
s.
December 18, 1984 ANPP-31527-TDS/TRB U. S. Nuclear Regulatory Commission Region V 1450 Maria Lane - Suite 210 Walnut Creek, CA 94596-5368 Attention: Mr. D. F. Kirsch, Acting Director Division of Resident Reactor Projects and Engineering Program
Subject:
Final Repo:.t - DER 84-53 A 50.55(e)
Reportable Condition Relating to Bonnet and Diaphragm Nuts and Bolts Loose on PC and CH Valves File: 84-019-026; D.4.33.2
Reference:
A) Telephone Conversation between P. Narbut and T.
Bradish on August 17, 1984 B) ANPP-30533, dated September 17, 1984 (Interim Report)
C) ANPP-31045, dated November 2,1984 (Time Extension)
D) ANPP-31161, dated November 16, 1984 (Time Extension)
E) ANPP-31256, dated November 29, 1984 (Time Extension)
Dear Sir:
Attached is our final written report of the deficiency referenced above, which has been determined to be Not Reportable under the requirements of 10CFR50.55(e).
Very truly your OAA.\\ (,)(\\ LOL {
N E. E. Van Brunt, Jr.
APS Vice President, Nuclear Production ANPP Project Director EEVB/IRB: dim Attachment cc:
See Page Two 8501070627 841218 PDR ADOCK 05000528 S
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1 Mr. ' D. F. Kirsch DER 84-53 Page Two ec:
Richard-DeYoung, Director Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, D. C.
20555 T. G. Woods, Jr.
D. B. Karner W. E. Ide D. B. Fasnacht A. C.. Rogers L. A.-Souza D. E. Fowler T. D. Shriver
-C.~ N. Russo B. S. Kaplan l
J. R. Bynum J. M. Allen D. Canady' A. C. Gehr W..J. Stubblefield W. G. Bingham R. L. Patterson R. W. Welcher H. D. Foster D. R. Haw'kinson R. P. Zimmerman M. L. Clyde M. Woods T. J. Bloom Records Center Institute of Nuclear Power Operations 1100 circle 75 Parkway, Suite 1500 Atlanta, GA 30339 D. N. Stover
FINAL REPORT - DER 84-53 DEFICIENCY EVALUATION 50.55(e)
ARIZONA PUBLIC SERVICI COMPANY (APS)
PVNGS UNITS 1, 2, 3 I.
Description of Deficiency During NRC Inspection 530/84-07 valve No. 3P-SIE-V235 was discovered lacking full thread engagement on the bonnet stud nut.
This nonconformance was documented on NCR No. PC-8259.
As a result of this finding', APS initiated CAR No. 884-053D.
The CAR recommended revising the existing procedures to give specific requirements for thread engagement.
During this period of - evaluation, valve No.
3P-SIE-V543 was discovered with loose nuts and documented on NCR No.
PC-8509.
Bechtel Construction was also inspecting a random samp12 of valves -and discovered valve No. 3P-SIE-V245 was lacking full thread engagement.
This was documented on NCR No. PC-8842.
Valve No. 3P-SIE-V237 was discovered lacking full thread engagement and was documented on NCR No. PC-9321. After valve Nos. 3P-SIE-V235 and 32-SIE-V245 were reworked per NCR Nos.
PC-8259 and PC-8842, respectively, the NRC reinspected valve No. 3P-SIE-V235 and Bechtel subsequently reinspected valve No. 3P-SIE-V245 and found them to be still lacking full thread engage-ment.
These conditions were documented on NCR Nos. PC-9320 and PC-9352.
During a Quality Assurance Audit of WPP/QCI 207.0, Rev. 9, "Disas-sembly and Reassembly of Quality Class "Q",
"R",
and "S"
- Valves, a
number of valves were discovered with bolting deficiencies.
As a result audit No. QAF 101-S-84-37-A reviewed forty-one additional valves.
The review discovered loose and/or missing her bonnet nuts in twelve valves and in diaphragm valve stud nuts which were in a less than flush condition in the valve body. and/or nut in nine i
valves.
The audit also reported that Specification 13-PM-204 for
" Nuclear Fuel Fabrication and Installation of Piping Systems" and Procedure WPP/QCI 207.0 for " Disassembly and Reassembly of Quality Clas s "Q",
"R",
and "S" Valves lack the requirements of the ASME Code to define the proper thread engagement.
These nonconforming conditions were documented on NCR Nos. PX-9264 and PX-9265 for Units 2 and 3, respectively.
A.
General In order to determine the potential extent of the conditions described in Section I, an inspection program was conducted to assure that valves would perform their required safety func-tion.
The inspection was conducted on Unit 2 and 3 only, however the results of the. inspection would be applicable to Unit 1 for the following reasons:
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i Final Report DER 84-53 Page Two
- 1. The same manufacturers supplied the valves for all three units.
- 2. The Unit i valves were installed in accordance with the same procedures.
- 3. The Unit 1 valves have already been subjected' to normal operating parameters.
- 4. Access to Unit 1 for an inspection is difficult.
The sample size was selected, similar to that necessary, to provide assurance, within a 95% confidence level, that at least 95% of the valves potentially ' subject to the type of deficiencies previously found would be satisfactory.
Two types of deficiencies were considered:
Nut / stud engagement Stud to valve bonnet engagement In each case, a sufficient sample of valves, distributed among the applicable vendors, was established based on the total three-unit population of applicable valves to assure compli-ance with the stated criteria.
Special SCIP's were prepared to document the inspection.
B.
Nut / Stud Engagement Procedures to reinspect her bonnet nut engagement were gener-ated _under SCIP Nos. 569.0 and 570.0.
These procedures required the inspection of 125 valves in both Units 2 and 3.
The inspection required the hex bonnet nuts to be checked for full thread engagement on assorted valve types (i.e.,
diaphragm, swing check, manual gate, etc.).
The sample consisted of valves from three suppliers:
- Dresser, Anchor / Darling, and ' Kerostat.
Her bonnet nut engagement for valves supplied from Borg Warner and ITT Grinnell were not inspected since they were addressed in the survey associated with the NRC inspection.and the Bechtel Quality Assurance Audit.
The inspections of B/W and ITT-Grinnell valves did not identify any safety-related conditions.
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r Final Report DER 84-53 Page Three The sample size consisted of 250 valves in. Units 2 and 3 out of a total valve -population for all three units of 2,056 valves.. For a 95% confidence that 95% of, the installations are acceptable, a total of 7 deficiencies < would have been allowed.
The incpection results show that no-deficiencies were discovered in Unit 2 and two deficiencies in Unit,3.
The deficiencies were documented on NCR No.
PF-9128.
Per discussion with Anchor Darling, a lack of 1/32" for one bolt will not create a safety problem.
Per discussion with Dresser, a maxiwa permissible negative tolerance for full thread engagement would be 0.094 inches.
The actual lack of full thread engagement is 0.046 therefore, this also would not be a safety problem.
Based on the results that no unacceptable conditions exist, the project has adequate confidence that valves previously installed in'Unita 1, _2 and 3 are acceptable for their inten-ded use and no further inspection is required.
C.
Stud to Valve Bonnet Engagement A procedure was developed to reinspect the thiead engagement from the bonnet stud into a valve.
These procedures ' were -
generated under SCIP Nos. 617.0 and 618.0.
The inspection required the valve bonnet studs to be checked for the required thread engagement of assorted valve _ types (i.e.,
diaphragm, swing check, manual gate, etc.).
The sample - consisted of valves from six suppliers:. Dresser, Anchor / Darling, Fisher, Borg Warner, Crosby and ITT Grinnell.
The sample size consisted of 283 valves' in Units 2 and 3 out of a total valve population for all three units, of 3,186 valves.
For a 95% confidence that 95% of the installations are acceptable, a total of 8 deficiencies would have been allowed.
The inspection results show that no deficiencies were dis-covered in Unit 2 or in Unit 3 (NCR Nos. PA-9828 and PA-9830 were written to document potential problems.
Based on subse-quent manufacturer clarification, these are no longer noncon-formances and will be dispositioned as such).
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Final Report DER 84-53.
Page Four Based on the results that no unacceptable conditions exist, l
the project has ' adequate confidence that valves previously installed in Units 1,
2 and 3 are acceptable for their intended use and no further inspection is required.
D.
NRC Inspection s
The NRC inspec' tion identified potential problems with - Borg Warner swing check valves.
These _ swing check-valves are designed in such a. manner that the studs which are used to d
hold down the spacer bonnet are not a load carrying compon-ent.
The studs are used only to hold the valve bonnet snug i.
against the valve seal when the system is' not pressurized.
During operation of the piping system, 'the internal pressure will force the bonnet up against the valve seal. negating the need for the studs and the requirement for the minimum thread
~
engagement. Prior to operation, the piping system is pressur-ized to 125 percent of its design pressure, and any problem j
with the bonnet or valve seal would be detected them. Lack of minimum thread engagement will not impact the safety of the valve or system.
(Reference JCR Nos.
PC-8259, PC-8509, j
PC-8842, PC-9320, PC-9321, and PC-9352).
Even though a number of NCR's required rework as given in Paragraph III.A, the work was completed on Borg Warner manufactured valves on.a discretionary basis since the. rework was determined as non-safety-related.
Since this rework 'was not required to ensure safety, no further inspection or rework is required, but will be performed when applicable under Para-graph III.C.
E.
Bechtel Audit Inspection The Bechtel Quality Assurance Audit of WPP/QCI 207.0 identi-l fled potential problems with 'ITT Grinnell diaphragm valves.
l The problem of missing / loose nuts described on the NCR's are not considered to be significant because of the type of. valve involved (i.e., diaphragm valves).
Until such time as rated pressure and temperature is reached, it would be possible that loose nuts would be found.
The ITT Grinnell valve installa-l tion manual states "the bonnet nuts should not be overtight--
l ened..Only a slight squeezing of the diaphragm.is necessary.
If leakage occurs around outer edge of diaphragm after rated pressure and ~ temperature is reached, retighten bonnet nuts".
.Because there is no torque value to attain and a slight squeezing of the diaphragm" is subjective, the liklihood of loose nuts is possible but doce not pose a
problem.
.c (Reference NCR Nos. PX-9262 and PX-9265).
I I
Final Report DER P4-53 Page Five Even though a number of - NCR's required rework as given in Paragraph III.A, the work was completed on ITT Grinnell manufactured valves on a discretionary basis since the rework was determined as non-safety-related. 'Since this rework was not required to ensure safety, no further inspection or rework
.is required, but will be performed when applicable under Para-graph III.C.
F.
Summary Based on the results of the overall inspection program, it can be concluded that no safety. significant deficiency exists relative to the bolting on the subject valves.
Therefore, it is concluded that no further inspection is warranted.
Ihc root cause of the deficiency was the lack of specific acceptance criteria for thread engagement.
This procedural item has been corrected as discussed in Section
- III, Corrective Action.
Procedural requirements for system walkdowns in the WPP/QCI's that address loose / missing nuts and bolts in valves are as follows:
A.
WPP/QCI 31.0, Subsystem Transfer / Acceptance, Paragraph 6.5.7 "Where practical, inspect for loose nuts and bolts (i.e.,
hanger supports, flanges, etc.).
B.
WPP/QCI 202.0, Piping Systems Installation, Appendix. IX C.6.D(d)
" Verify that all visible vendor bolts, studs and nuts are present and intact".
The missing nuts were all in Unit 3 and would have been identified at the time of subsystem walkdown.
II.
Analysis of Safety Implications Based upon the above, this condition is evaluated as not reportable under 10 CFR Part 50.55(e) and Part 21 since, if 1cft uncorrected, it would not be a significant safety hazard.
l Final Report DER 84-53 Page Sir III. Corrective Action A.
The following NCRs were evaluated and will have the following actions:
1.
.NCR No. PC-8259 was dispositioned Rework.
2.
NCR No. PC-8509 was dispositioned Rework.
3.
NCR No. PC-8842 was dispositioned Rework.
4.
NCR No. PF-9128 was dispositioned Use.As-IsMRework.
5.
NCR No. PX-9264 will be dispositioned Use-As-Is/ Rework.
6.
NCR No. PX-9265 will be dispositioned Use-As-Is/Rewark.
7.
NCR No. PC-9320 will be dispositioned Use-As-Is.
8.
NCR No. PC-9321 will be dispositioned Use-As-Is.
9.
NCR No. PC-9352 will be dispositioned Use-As-Is/ Rework.
- 10. NCR Nos. PA-9829 and PA-9830 are no longer nonconforming conditions due to revised criteria by the valve manufac-turer.
Item 5 through 9 will be dispositioned by December 21, 1984.
B.
To preclude recurrence of this type problem, the following documents have been generated to specify the acceptable thread engagement:
FCR No. 82,404 to Specification 3-PM-204 FCR No. 84,746 to Specification 3-PM-204 FCR No. 82,402 to Specification 3-HH-510 PCN No. 15 to WPP/QCI 151.0 PCN No. 3 to WPP/QCI 156.0 PCN No. 152 to WPP/QCI 201.1 PCN No. 169 to WPP/QCI 202.0 PCN No. 24 to WPPiqCI 207.0 PCN No. 31 to WPP/QCI 207.0 PCN No. 20 to WPP/QCI 350.0
Final Report DER 84-53 Page Seven 4
C.
. Procedural requirements will be expanded to include in WPP/QCI 202.0 " Piping Systems Installation" that thread engagement will be verified upon acceptance of valve installation.
WPP/QCI 201.0 " Disassembly and Reassembly of Quality Class "Q"
"R",
and "S" Valves _ will be revised to include verifica-tion of : thread engagement upon reassembly of valves.
These changes will be' incorporated by January 1, 1985.
D.
Training sessions were held in June and August 1984 to discuss with required AFE's and QC personnel about the acceptable thread engagement.
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