ML20213A457
| ML20213A457 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 01/23/1987 |
| From: | TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML20213A334 | List: |
| References | |
| 222.5(B), 222.5(B)-R02, 222.5(B)-R2, NUDOCS 8702030288 | |
| Download: ML20213A457 (13) | |
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4 TVA EMPLOYEE CONCERNS REPORT NLMBER: 222.5 (B)
SPECIAL PROGRAM i
REPORT TYPE:
SEQUOYAH ELEMENT REVISION NUMBER:
2 TITLE:
PIPE SUPPORT WELD DESIGN Bolts Replaced by Weld PAGE 10F 12 REASON FOR REVISION:
1.
To incorporate consents by SRP, TAS, and TVA; to include TVA's corrective action plan infomation (see Section 10); and to comply with current format.
2.
Revised Section 10, Corrective Action, to incorporate further coments by SRP and TAS; revised Appendix A, Section 5, to add RIMS numbers.
PREPARATION PREPARED BY:
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' DATE SIGNATURE DATE 88 OA APPROVED BY:
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ECSP MANAGER' DATE' MANAGER OF NUCLEAR POWER DATE CONCURRENCE (FINAL REPORT ONLY)
SRP Secretary's signature denotes SRP concurrences are in files.
TVA EMPLOYEE CONCERNS REPORT IRSSER: 222.5 (B)
SPECIAL PROGRAM REVISION NLSEER:
2 PAGE 2 0F 12 1.
CHARACTERIZATION OF ISSUE (S):
Concern:
Issue:
IN-85-109-002 When a mixed bolt and weld design
" Bolts replaced by welding to is made, the weld should be designed embedded plates. The CI is of to carry entire shear load, the opinion that the weld should be analyzed for carrying the entire load.
( Aux. Building, Elev. 747' or 757', Unit 1 & 2)
Two internal memos (correspond-ence known) describe this con-dition. Time frame was July 1983."
2.
HAS ISSUE BEEN IDENTIFIED IN ANOTHER SYSTEMATIC ANALYSIS? YES X NO Identified by TVA Date See below Documentation Identifiers:
a.
Problem Identification Report, PIR WBN CEB 8573, (B41851220 016) (12/20/85) b.
Significant Condition Report, SCR SQN CEB 8601, (B41860110 021) (01/03/86) c.
Engineering Report for CAQ Report No. SCR SQN CEB 8601, (B25 860123 003) (01/23/86) d.
Nuclear Safety Review Staff (NSRS) Investigation Report No, I-85-248-WBN, (11/07/85) 3.
DOCtMENT NOS., TAG NOS., LOCATIONS OR OTHER SPECIFIC DESCRIPTIVE IDENTIFICATIONS STAILD IN ELEMENT:
o Auxiliary Building, Elev. 747' or 757', Units 1 and 2 o
Two internal memos o
Time frame, July 1983 i
l This applies only to Watts Bar (WBNP) l l
l'" Y - 01/12/87
TVA EMPLOYEE CONCERNS REPOR1 NUMBER:
222.5 (B)
SPECIAL PROGRAM REVISION NUMBER:
2 PAGE 3 0F 12 4.
INTERVIEW FILES REVIEWED:
Review of interview files for concern IN-85-109-002 shows the following information:
o K-forms: 001, 00/, 003, X04 and 005 o
A 55-page typed statement of the interview held between concerned individual (CI) and two interviewers, o
Memos and 45 "D" forms between CI and supervisor.
o NSRS Report I-85-248-WBN o
PIR WBNCEB 8573 5.
DOCUMENTS REVIEWED RELATED TO THE ELEMENT:
See Appendix A.
6.
WHAT REGULATIONS, LICENSING C009tITMENTS, DESIGN REQUIREMENTS, OR OTHER APPLY OR CONTROL IN THIS AREA?
See Appendix A.
7.
LIST REQUESTS FOR INFORMATION, MEETINGS, TELEPHONE CALLS, AND OTHER DISCUSSIONS RELAltu TO ELEMENT.
See Appendix A.
8.
EVALUATION PROCESS:
a.
Reviewed design criteria and 47A050 series drawing notes for mixed bolted and welded connection requirements.
b.
Reviewed applicable codes.
c.
Selected pipe supports having mixed bolted / Welded connection for review.
d.
Reviewed support calculations for design assumption and distribution of loads among bolt and weld.
I 1034d - 01/12/87
TVA EMPLOYEE CONCERNS REPORT NLM ER: 222.5 (B)
SPECIAL PROGRAM REVISION NUMBER:
2 PAGE 4 0F 12 9.
DISCUSSION, FINDINGS, AND CONCLUSIONS:
Chronology:
02/78:
Drawings 47A050-01 and -02 issued 05/85:
TVA receives the employee concern 11/85:
Nuclear Safety Review Staff (NSRS) Investigation Report No. I-85-248-WBN issued 12/85: o Problem Identification Report (PIR) WBNCEB 8573 issued o
Memo from R. O. Barnett to Those Listed,
Subject:
Policy Memorandum PM 86-17 (CEB) - Structural Steel Connections Combining Welds and Bolts (including baseplate connections) 01 /86: o Significant Condition Report (SCR) SQNCEB 8601 issued o
Engineering Report for CAQ report No. SCR SQNCEB 8601 issued Discussion:
A mixed bolt and weld design is used when a surface-mounted base plate overlaps an adjacent embedded plate so that one or more of the anchor bolts cannot be installed. Welding is substituted for anchor bolts on the portion of the base plate overlapping the embedded plate.
The CI's opinion is that this weld should be designed to carry the entire load for that base plate.
A similar concern is being investigated under Sequoyah Element Report 215.9 (B) titled " Civil / Structural Design - Structural Steel Connection Design."
The assumption by the CI that the entire load (tension and shear) must be carried by the weld is overly conservative since only the entire shear load is carried by the weld, as explained below.
Section 7.15.1.1 of Pipe Support Design Manual stipulates that the weld design calculation shall be performed in accordance with the American Institute of Steel Construction (AISC) code. Section 1.15.10 of AISC code contains the design criteria for the use of bolts in combination with weld:
1034d - 01/12/87
TVA EMPLOYEE CONCERNS REPORT NLMBER: 222.5 (B)
SPECIAL PROGRAM REVISION Hl#EER: 2 PAGE 5 0F 12 "A-307 bolts, or high strength bolts used in bearing-type connections shall not be considered as sharing the stress in combination with welds.
Welds if used shall be provided to carry the entire stress in the connection.
High strength bolts installed in accordance with the provisions of Section 1.16.1 as a friction type connection prior to welding may be considered as sharing the stress with welds.
The intent of this code is that, since slippage can occur for shear forces in bearing-type connections, the relatively rigid weld will carry the shear load in case of connections with mixed welding and bearing-type bolts.
TVA has generally used wedge bolts or grouted anchors for pipe support base plates. Since these are not high strength bolts, the base plate connections used in pipe supports cannot be considered as friction-type and do not bear the shear load but shift it to the weld.
WBNP drawing 47A050-10 permitted construction personnel to substitute fillet welds in place of concrete anchors when a surface mounted plate overlapped an embedded plate.
Engineering approval was not required. WBNP found that these welds were not designed to carry the entire shear load and, therefore, a Problem Identification Report (PIR) (App. A, 5.a) was issued.
As a result of this PIR, the following corrective actions are being taken by WBNP:
a.
Conduct a field survey sampling of plates in which this condition exists to determine worst in-place condition.
b.
Evaluate the worst case condition by either an analytical procedure or by testing (if required).
c.
Revise notes on drawing 47A050-10 as required for future installations.
d.
Locate, evaluate, and revise all surface-mounted plates for whicli this condition exists, only if sampling program results are unacceptable.
e.
Complete all design work per ECN 6194 (Ul) and 6195 (U2).
1034d - 01/12/87
TVA EMPLOYEE CONCERNS REPORT Nt3BER: 222.5 (B)
SPECIAL PROGRAM REVISION Nt3BER: 2 PAGE 6 0F 12 Sequoyah (SQN) drawings 47A050-1 and 2 (all revisions) also permit construction personnel to substitute fillet weld for concrete anchors when a surface mounted plate overlaps an embedded plate.
However, they require Office of Engineering (OE) approval for this substitution, q
As a followup to WBNP, SQN issued a Significant Condition Report (SCR) for a potential generic condition of mixed bolted and welded connections and to determine if this condition existed at SQN Plant (Sec. 2.b).
In response to this SCR, an Engineering Report (Sec.
2.c) concluded that no failure will occur for the following reasons:
a.
A review of engineered supports did not reveal any places where the weld detailed in note II-2 on drawing 47A050-2 R5 was used (5/16-inch fillet weld, 2 inches long).
b.
A review of the loads that could possibly be applied to any of the typical supports did not find any loads high enough to cause the welded connection to fail under the assumption that the weld carries the entire load, c.
Calculations show that the weld is qualified for all but tha most unusual load case (i.e., all shear, no tension or moment on base plate), and since OE approval is required in the form of a Field Change Request (FCR) before the field can use the weld information contained in the note, OE personnel would be responsible for verifying the adequacy of the weld before approving an FCR.
The generic calculation for item "c" above was reviewed by the evaluation team.
The shortcomings are noted below:
a.
The expansion anchors shared shear loads with welds contrary to the AISC code requirements.
b.
To determine the ultimate load carrying capacity of the weld, the capacity of the base metal which could be gove ning was not considered.
c.
In a case where welding was substituted for 1-inch-diameter anchor, the actual load in the weld under shear loading exceeded the ultimate capacity.
1034d - 01/12/87
TVA EMPLOYEE CONCERNS REPORT NLMBER: 222.5 (B)
SPECIAL PROGRAM
, Q REVISION NLMBER: 2
'3 PAGE 7 0F 12 If this generic calculation is an indication of common design practice at SQN for mixed bolt end weld connections, the evaluation team does not concur with the desis's asstanptions.
(The evaluation team was unable to verify this because requested calculations for two supports [ App. A, 5.k] were nct in SQN records).
Corrective actions similar to those taken at,WBNP should be considered.
f Findings:
s, x.
a.
Drawings 47A0%-1 and 2 pennit constructi6n personnel to substitute fiilet weld for concret.e ' anchors when a surface mounted plate overlaps an embedded pinte. However, OE approval is required for such substitution.
b.
The cniculation perfonned to qualify mixed bolt and weld connection for SCR SQN CEB 8601 does not satisfactorily address the instructions of pipe. support design criteria.
c.
Design calculation for the two supports with mixed bolted and welded connection could not be found in SQN records.
==
Conclusions:==
The concern is valid that for a mixed bolt and weld connection, the weld must be designed to carry the entire shear load. Calculations perfonned for SCR SQN CEB 8601'ao r.ot satisfactorily address the s
concern.
't 41 0.
CORRECTIVE ACTION: 1 In its corrective action plan (CAD)a' App.i A, 5.v), TVA commits to
~
s perform a random sampling program of 60 baseplates with cambined welds and bolted connections. This random sample will be selected by drawing review and field walkdown for piping, HVAC ducts, cable trays, conduits, and steel platfonns in Auxiliary Building, Control Building, Reactor Building (RB) shield wall, RB crane wall, and i
reactor cavity wall.
I The sample will be analyzed by distributing all shear forces applied on the baseplate to the weld. A sample will be considered acceptable if the actual calculated ' stress in the weld is less than s
the allowable stress.
If no failures are identified in the sample, then a 95 percent confidence level will have been established.
If failures are encountered in the sample, then the sample will 1034d - 01/12/87
TVA EMPLOYEE CONCERNS SPECIAL PROGRAM REPORT NUMBER: 222.5 (B) l REVISION NUMBER: 2 PAGE 8 0F 12 be expanded until 95 percent confidence level in 95 percent conformance is achieved.
the sample size would have to be increased to 93 to achieve a 9 perccnt confidence level in 95 percent confomance and so on.
additonal failures are encountered, the sample size may reach to If will have to be perfomed.the size of the population; in that case, a 100 p The connections that are found deficient in welding will be strengthened.
j instructions for designing structural connections that u i
combination of welds and bolts.
this type of problem in the future.This should prevent recurrence of The evaluation team concurs with the CAP.
103dd - 01/12/87
TVA EMPLOYEE CONCERNS REPORT NLMBER: 222.5 (B)
SPECIAL PROGRAM REVISION NLDEER: 2 PAGE O 0F 12 be expanded until 95 percent confidence level in 95 percent conformance is achieved. For example, if one failure is enccunted, the sample size would have to be increased to 93 to achieve a 95 percent confidence level in 95 percent confomance and so on.
If additonal failures are encountered, the sample size may reach to the size of the population; in that case, a 100 percent inspection will have to be perfomed.
The connections that are found deficient in welding will be l
strengthened.
In addition, policy memorandum PM-86-17 ( App. A, 5.n) provides the instructions for designing structural connections that utilize a combination of welds and bolts.
This should prevent recurrence of this type of problem in the future.
The evaluation team concurs with the CAP.
I i
l l
l i
1034d - 01/12/87 l
TVA EMPLOYEE CONCERNS REPORT NLMBER: 222.5 (B)
SPECIAL PROGRAM REVISION NLM ER: 2 PAGE 9 0F 12 APPENDIX A 5.
DOCtMENTS REVIEWED RELATED TO THE ELEMENT:
a.
PIR WBN CEB 8573, (B41 851220 016) (12/20/85) b.
SCR SQN CEB 8601, (B41860110 021) (01/03/86) c.
Engineering Report for CAQ Report No. SCR SQN CEB 8601, (B25 860123 003) (01/23/86) d.
NSRS Investigation Report No. I-85-248-WBN, (11/07/85) (no l
RIMS number) e.
Memo from R. O. Barnett to Those Listed, (B41 851220 017).
Subject:
Potential Generic Condition Evaluation - Problem Identification Report (PIR WBN CEB 8573) - Bolt Replacement Welds for Surface-Mounted Plates, (12/20/85) f.
Pipe Support Design Manual, Section No. 7.14, " Concrete Anchorages," Rev. 3, (07/23/84) g.
Pipe Support Design Manual, Section No. 7.15 " Design of Welded Connections," Rev. 2, (07/23/84) (no RIMS number)
I h.
Civil Design Standard DS-C1.7.1 " General Anchorage to Concrete," Rev. 3, (11/16/8e) (CEB 841121 501) l 1.
American Institute of Steel Construction Manual, 7th Edition J.
-2, and -16, " Mechanical Hanger Drawing General Notes" k.
Support Drawings:
i 1-FPCH-505(H50-505)/R1, (1/21/81) 2-CCH-367 (2-H10-367)/R902, (3/8/86) and R1, (4/10/80) 1.
Nuclear Performance Plan (NPP), (L44 860714 800), Volme II, Rev.1, (7/14/86) m.
TVA DNE Calculations, "For SCR SQN CEB 8601" (B24 860906 300) n.
TVA memo from R. O. Barnett to Those Listed,
Subject:
" Policy Memorandum PM 86-17 (CEB) - Structural Steel Connections Combining Welds and Bolts (Including Baseplate Connections)," (B41 860911 011) (09/11/86) 1034d - 01/12/87
TVA EMPLOYEE CONCERNS REPORT NLMER: 222.5 (B)
SPECIAL PROGRAM REVISION NLMBER: 2 PAGE 10 0F 12 APPENDIX A (cont'd) o.
TVA memo from R. G. Domer to W. T. Cottle,
Subject:
" Watts Bar Nuclear Plant - Employee Concern Investigation Report 1-85-248-WBN, Employee Concern IN-85-109-002," (03/03/86) (no RIMS number) p.
TVA memo from K. W. Whitt to W. T. Cottle,
Subject:
" Corrective Action Response Evaluation," (01/22/86) (no RIMS number) q.
TVA memo from J. C. Standifer to W. T. Cottle,
Subject:
" Watts Bar Nuclear Plant - Employee Concerns," (01/09/86)
(T25 860423 097) l r.
TVA memo from W. T. Cottle to K. W. Whitt,
Subject:
" Watts Bar Nuclear Plant - Response to Employee Concern Investigation Report I-85-248-WBN (Employee Concern Number IN-85-109-002)," (01/07/86) (T25 860317 929) l s.
TVA memo from J. L. Standifer to W. T. Cottle,
Subject:
" Watts Bar Nuclear Plant - Employee Concern Investigation Report I-85-284-WBN, Employee Concern IN-85-109-002,"
(01/03/86) (no RIMS number) l t.
TVA memo from W. T. Cottle to J. L. Standifer,
Subject:
" Watts Bar Nuclear Plant - Responses to Employee Concern Investigations," (01/02/86) (T25 860317 924) l u.
TVA memo from J. C. Standifer to E. R. Ennis,
Subject:
" Watts Bar Nuclear Plant - Employec Investigation Report I-85-248-WBN Response," (12/17/85) (no RIMS number) l v.
TCAB-049, Corrective Action Plan (CAP) for Element 222.5(B),
(12/30/86) 6.
WHAT REGULATIONS, LICENSING COPWITNENTS, DESIGN REQUIREMENTS, OR OTHER APPLY OR CONTROL IN THIS AREA?
a.
Anerican Institute of Steel Construction Manual, 7th Edition b.
Pipe Support Design Manual, Section No. 7.14, " Concrete Anchorages," Rev. 3, (07/23/84) c.
Pipe Support Design Manual, Section No. 7.15 " Design of Welded Connections," Rev. 2,(07/23/84) d.
Civil Design Standard DS-C1.7.1, " General Anchorage to Concrete," Rev. 3, (11/16/84) h-- RiL6PM@7
TVA EMPLOYEE CONCERNS REPORT NUMBER: 222.5 (B)
SPECIAL PROGRAM REVISION NUMBER: 2 PAGE 11 0F 12 APPENDIX A (cont'.d) 7.
LIST REQUESTS FOR INFORMATION, MEETINGS TELEPHONE CALLS, AND OTHER DISCUSSIONS RELATED TO ELEENT.
a.
RFI #SQN-515, (08/24/86) b.
RFI #SQN-546, (09/09/86) c.
TVA Transmittal No. 102, (08/29/86) d.
RFI #SQN-595, (09/26/86) e.
Telecon between N. Liakonis, L. Katacham, R. Hoekstre, TVA, and S. Chitnis, Bechtel, IOM #277, (09/26/86) 1034d - 01/12/87
]
TVA EMPLOYEE CONCERNS REPORT NLMBER: 222.5 (B)
SPECIAL PROGRAM REVISION NLMBER: 2 PAGE 12 0F 12 CATD LIST The following CATD identifies and provides corrective action for the findings included in this report:
222 05 SQN 01 (11/06/86) 1034d - 01/12/87
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REFERENCE
- ECPS120J-ECPS121C TENNESSEE VALLEY AUTHORITY PAGE 102 FREQUENCY
- REQUEST OFFICE OF NUCLEAR POWER RUN TIME - 12:57:19 I
. )
ONP - ISSS - RHM LIST OF EMPLOYEE CONCERN INFORMATION EMPLOYEE CONCERN PROGRAM SYSTEM (ECPS)
RUN DATE - 12/02/86 CATEGORY: EN DES PROCESS & OUTPUT SUBCATEGORY: 22205 BOLTS REPLACED BY HELD 1
)
S GENERIC KEYHORD A H
APPL QTC/NSRS P
KEYNORD B CONCERN SUB R PLT BBSH INVESTIGATION S
CONCERN KEYHORD C NUMBER CAT CAT D LOC FLQB REPORT R
DESCRIPTION KEYNORD D
-)
IN 109-002 EN 22205 N HBN YYYY I-85-248-HBN SR BOLTS REPLACED BY HELDING TO EMBEDDE HELDING T50083 REPORT D PLATES. THE C/I IS OF THE OPINION DESIGN PROCESS l'
THAT THE HELD SHOULD BE ANALYZED F0 NELDING
)
R CARRYING THE ENTIRE LOAD.
(AUX. B EMBEDS
.}
UILDING, ELEV. 737' OR 757', UNIT 1
& 2.)
THQ INTERNAL MEMOS (CORRESPON DENTS KNDHN) DESCRIBE THIS CONDITION I
i -)
TIME FRAME HAS Jo6Y 1983.
1 CONCERNS FOR CATEGORY EN SUBCATEGORY 22205 5)
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