ML20207L213

From kanterella
Jump to navigation Jump to search
Rev 1 to Sequoyah Element Rept, Pipe Support Design, Observed Bending of Pipe Clamp Ears
ML20207L213
Person / Time
Site: Sequoyah  Tennessee Valley Authority icon.png
Issue date: 12/30/1986
From: Russell Gibbs
TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20207K584 List:
References
221.6-(B), 221.6-(B)-R01, 221.6-(B)-R1, NUDOCS 8701120017
Download: ML20207L213 (9)
v • d • e


Text

.

. TVA EMPLOYEE CONCERNS REPORT NUMBER: 221.6 (B)

SPECIAL PROGRAM REPORT TYPE: SEQUOYAH ELEMENT REVISION NUMBER:

{ 1 TITLE: PIPE SUPPORT DESIGN Observed Bending of Pipe Clamp Ears PAGE 1 0F 8 REASON FOR REVISION:

1. To incorporate SRP and TAS comments, to include TVA's corrective action plan information (See Section 10), and to comply with current format.

PREPARATION

( .- PREPARE  :

L V

I3I SIGNATURE v2.- u- 8(,

DATE REVIEWS IEW COMMIT lb ~

S E

' # w: R lY! [6 DATE TAS P '

thera Sn R MJiew.rf SIGNATURE ru

/DATE l

CONCURRENCES 8701120017 870102 .

PDR ADOCK 05000327 -

P PDR cgg_y ) fptg,,p, jf.}g f 'V SRP: mki /00b /2 @(o SIGNATURE _ DATE

[ SIGNATUK*/

  • SRP Secretary's signature denotes SRP concurrences are in files.

DATE j ,

k APPROVED BY:

s.((\ 3 W h . 11._ __ i.?l?t lpt . N/A l U ECSP MANAGER DATE '- MANAGER OF NUCLEAR POWER DATE j ( CONCURRENCE (FINAL REPORT ONLY)

1 a

TVA EMPLOYEE CONCERNS REPORT NUMBER: 221.6 (B)

SPECIAL PROGRAM REVISION NUMBER: 1

(._

PAGE 2 0F 8 l

1. CHARACTERIZATION OF ISSUE (S):

Concern: Issues:

IN-85-305-001 a. Excessive torque on bolts caused l "Over a period of time the bending of clamp ears.

bending of ears on small 8001 support clamps will cause the b. Clamps were modified to A-36 material to yield beyond prevent this bending but l its yield point. Clamps are the clamp manufacturer's installed in both units. (WBNP)." concurrence was not obtained.

2. HAVE ISSUES BEEN IDENTIFIED IN ANOTHER SYSTEMATIC ANALYSIS? YES X NO Identified by Quality Technology Company (0TC) l Date 03/25/86 Documentation Identifiers:

Employee Response Team (ERT) Investigation Report for Watts Bar l Nuclear Plant (WBNP) employee concern No. IN-85-305-001.

(

3. DOCUENT NOS., TAG NOS., LOCATIONS, OR OTHER SPECIFIC DESCRIPTIVE IDENTIFICATIONS STATED IN ELEMENT.

B001 Support Clamps A-36 Material Both units (WBNP)

4. INTERVIEW FILES REVIEWED:

Review of interview files for concern No. IN-85-305-001 shows the following information:

o Generic applicability determination form (Form G-A) o Employee concern assignment request (K-form) o ERT invesitgation report by QTC (03/26/86) o Request for reportability evaluation (ERT Form M) k 0995d - December 09, 1986

l TVA EMPLOYEE CONCERNS REPORT NUMBER: 221.6 (B)

SPECIAL PROGRAM REVISION NUMBER: 1 <

l l PAGE 3 0F 8  ;

5. DOCUMENTS REVIEWED RELATED TO THE ELEMENT:

See Appendix A.

6. WHAT REGULATIONS, LICENSING C0PMITMENTS, DESIGN REQUIREMENTS, OR OTHER APPLY OR CONTROL IN THIS AREA?

See Appendix A.

7. LI.cf REQUESTS FOR INFORMATION, MEETINGS, TELEPHONE CALLS, AND OTHER

@CUSSIONSRELATEDTOELEMENT.

See Appendix A.

8. , EVALUATION PROCESS:
a. Investigated toque value specified for SQN for B001 support l clamps.

c' b. Performed calculation te determine if SQN specified toque is l k excessive and could cause bending of ears.

c. Determined if these clamps were modified by welding l

stiffeners to them to prevent them from bending, d Ascertained if vendor approval was obtained and documented if the clamps were modified. l

9. DISCUSSION, FINDINGS, AND CONCLUSIONS:

Chronology:

08/12/76: Revision 0 of drawing 47B001-12 issued. Toque values for run line clamps are specified in this document.

l 07/19/77/ Revision 0 of drawings 478001-14 and 47B001-14A 02/07/78: issued. Toque values for branch line clamps are specified in these documents.

l 07/01/77: Civil Engineering Branch (CEB) report No. 75-18, Rev.1 issued.

10/25/77: CEB Report No. 77-42 for static pipe support tests and development for Sequoyah (SQN) Units 1 and 2 issued.

l 0995d - December 09, 1986 l-

TVA EMPLOYEE CONCERNS REPORT NUMBER: 221.6 (B)

SPECIAL PROGRAM REVISION NUMBER: 1 ,

(~-

PAGE 4 0F 8 05/15/78: Current revision (Revision 5) of 478001-12 issued.

06/16/78 Current revisions (Revision 4) of 478001-14 and 06/78: (Revision 1) of 478001-14A issued.

05/22/84: Current revision (Revision 3) of CEB-75-18 issued.

05/31/85: TVA receives the employee concern.

03/25/86: ERT investigation report of this concern.

04/01/86: WBNP preliminary perception of the employee concern (memo from J. C. Standifer to R. G. Domer).

Discussion:

The concern as stated is that over a long period of time the ears on small 8001 support clamps will bend because of excessive torguing and that this bending will result in stressing A-36 i material beyond its yield point.

to B001 Seismic Category I type supports are used to support drain lines, instrument sensing lines, sampling lines, radiation monitoring lines, and test and process lines containing isolation valves. These lines are called branch lines. The supports consist of a stanchion pipe welded directly to the run line or to the clamp which is fastened to the run line. Similarly the branch line is welded or clamped to the stanchion. Adequacy of the branch line and run line clamp when over-torqued is the concern which will be addressed in this discussion, Drawings 478001-14,14A & -12 specify a tonaue value of 5 to 10 f t-lb (depending on the size of the bolt) for branch line clamps and 100 ft-lb for run line clamps (regardless of clamp and bolt size). The 100 ft-lb value may have arisen from a test program (App. A, 5.a and 5.e) that specified this value for Bergen-Patterson clamp #298 for all pipe sizes.

Drawing No. 478001-12, Rev. 5 and CEB Report No. 77-42 specify tonaue values for the bolts, whereas CEB Report No. 75-18, under the tabulation of parameterc for anchor clamp, specifies preload values for the bolts. To establish a relationship between preload and tonaue values, the evaluation team calculated tongue values for

(

i 0995d - December 09, 1986 I -

\

TVA EMPLOYEE CONCERNS REPORT NUM8ER: 221.6 (B) l SPECIAL PROGRAM REVISION NUMBER: 1 PAGE 5 0F 8 clamp sizes for 2-1/2-inch to 30-inch-diameter pipe. For comparison purposes, preload and toque values for a 3/4-inch-diameter bolt of a 2-1/2-inch-diameter pipe clamp are listed below:

Reference Preload (1b) Toque (f t-lb)

App. A, 5.d & 5.a --

100 App. A, 5.b 2,800 --

App. A, 5.c 2,800 42 (Bechtel calc.) 6,667*

  • Bolt load corresponding to 100 f t-lb toque value.

The above tabulation shows that a toque value of 100 f t-lb will produce a preload almost 2-1/2 times the value indicated in App. A, 5.b or, alternately, the actual toque required is about 40 percent of what was specified for installation of these clamps. Therefore, it is evident that the 8001 support clamps were over-stressed by over-toq uing of the bolts and the ears could have been bent, especially for smaller size pipe clamps. Instead of reducing the toque value to a value compatible to the bolt preload, WBNP welded stiffeners to these clamps to prevent them from bending. This is discussed in the ERT investigation report referenced in section 2.0. SQN did not weld stiffeners to the clamps.

Welding stiffeners to the clamps is likely to prevent bending of I clamp ears, but it causes the specified preload in the bolts to be exceeded. The excessive toque value for installation of these clamps should be reduced to be compatible with the capacity of the clamps and bolts. The clamps, if damaged or determined to be ineffective for their intended function, should be replaced and installed at the lower toque value equivalent to the specified bolt preload.

Findings:

a. There could be no bending of ears for the small bore pipe l branch line clamps because the toque values specified for their installation were reasonable.
k. .

0995d - December 09, 1986

TVA EMPLOYEE CONCERNS REPORT NUMBER: 221.6 (B) l SPECIAL PROGRAM REVISION NUMBER: 1 I PAGE 6 0F 8 There would be bending of ears for the run line clamps because excessive torque value was specified for their i installation. This excessive torque could also cause  !

-over-stressing and failure of clamp bolts.

b. SQN did not modify pipe clamps to prevent them from bending.

Conclusion:

The concern is valid for the run line clamps but not for the branch line clamps. The torque value specified in drawing 47B001-12, Rev. 5, for installation of B001 type support, is excessive. This excessive torque could cause bending of ears of clamps on the run line or overstress the bolts.

10. CORRECTIVE ACTION:

In its corrective action plan (CAP) (App. A, 5.g), TVA will revise drawing 478001-12 to provide appropriate bolt torque values for the clamps listed. A plant survey will be performed to identify and

(-' evaluate B001 type supports that may have been installed with excessive torque applied to the clamp bolts. The evaluation team concurs with this CAP.

(.

0995d - December 09, 1986

TVA EMPLOYEE CONCERNS REPORT NUMBER: 221.6 (B) l SPECIAL PROGRAM l REVISION NUMBER: 1

?

f' PAGE 7 0F 8 I

APPENDIX A

5. DOCUMENTS REVIEWED RELATED TO THE ELEMENT:
a. CEB Report No. 77-42, " Static Pipe Support Tests and Development - SQN 1 & 2," (10/25/77)
b. CEB Report No. 75-18, Rev. 3, "Small Line Attachment Details to Class 2 and 3 Piping Equal to or Larger Than 2-1/2 Inch Diameter," (05/22/84), Rev.1 (07/01/77)
c. Bechtel Calculation No. PD-221-14, (09/04/86)
d. Drawings 478001-1 through -17, titled " Mechanical Branch Valve Connection Seismic Support. Seismic Class I Structures"
e. Memo from J. C. Standifer to R. G. Domer, "WBNP - Employee Concern IN-85-305-001," (04/01/86)
f. Nuclear Performance Plan (NPP), Volume II, Rev. 1,(07/14/86) l

(":,: TCAB002, Corrective Action Plan (CAP), (11/05/86) g.

6. WHAT REGULATIONS, LICENSING C0pmITMENTS, DESIGN REQUIREMENTS, OR OTHER APPLY OR CONTROL IN THIS AREA?
a. Drawing 478001-12, Rev. 5, (05/15/78)
b. Drawing 478001-14, Rev. 4, (06/16/78)
c. Drawing 478001-14A, Rev.1, (06/78)
d. CEB Report No. 75-18, Rev. 3, (05/22/84)
7. LIST REQUESTS FOR INFORMATION, MEETINGS, TELEPHONE CALLS, AND OTHER
DISCUSSIONS RELATED TO ELEMENT.
a. TVA Transmittal #077, (07/17/86)
b. RFI #SQN-519, (08/28/86)
c. WBNP RFI #088, (05/29/86)

_ d. WBNP RFI #031, (04/17/86)

L 0995d - December 09, 1986 i

? -

TVA EMPLOYEE CONCERNS REPORT NUMBER: 221.6 (B)

SPECIAL PROGRAM REVISION NUMBER: 1 PAGE 8 0F 8 CATD LIST The following CATD identifies and provides corrective action for the findings included in this report:

221.06 SQN 01 (10/21/86)

-(:

f i

I l C l

l 0996d - December 09, 1986

w_ u - - ----

. . _ .m.m.,_ - - . _ - . _ _. _ m . _ _ _ . - -.__

.,(

'W. 3 '. ,. , .,_ AJ ?yQ,

~~o'.

!, .I . ' JM .. >:

fil .

-).

REFERENCE - ECPS120J-ECPS121C TENNESSEE VALLEY AUTHORITY PAGE -

97 FREQUENCY - REQUEST OFFICE OF NUCLEAR POWER RUN TIME - 12:57:19 l ONP - ISSS - RHM EMPLOYEE CONCERN PROGRAM SYSTEM (ECPS) RUN DATE - 12/02/86 LIST OF EMPLOYEE CONCERN INFORMATION CATEGORY: EN DES PROCESS & OUTPUT SUBCATEGORY: 22106 OBSERVED BENDING OF SMALL-BORE PIPE CLAMP EARS

) S GENERIC KEYHORD A H APPL QTC/NSRS P KEYHORD B CONCERN SUB R PLT BBSH INVESTIGATION S CONCERN KEYHORD C g NUMBER CAT CAT D LOC FLQB REPORT R DESCRIPTION KEYHORD D IN 305-001 EN 22106 N HSil YYYY SR OVER A PERIOD OF TIME THE BENDING OF PROCEDURES T50021 REPORT EARS ON SMALL B001 SUPPORT CLAMPS H INSTALLATION ILL CAUSE THE A-36 MATERIAL TO YIELD HANGERS 3- BEYOND ITS YIELD POINT. CLAMPS ARE PIPE INSTALLED IN BOTH UNITS CHBNP5 1 CONCERNS FOR CAT 5 .EGORY 22106

)

3 3

3 0 .

)

J

.)

)

_

Retrieved from "https://kanterella.com/w/index.php?title=ML20207L213&oldid=3047646"