ML20204G679
| ML20204G679 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 06/07/1984 |
| From: | Hartzman M, Kamal Manoly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I), Office of Nuclear Reactor Regulation |
| To: | Knight J Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20204G686 | List: |
| References | |
| FOIA-84-741, FOIA-84-741C, FOIA-84-742 NUDOCS 8407060327 | |
| Download: ML20204G679 (7) | |
Text
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'JUN 7 1984 MEMORANDUM FOR: James P. Knight, Assistant Director for Components & Structures Engineering Division of Engineering FROM:
Kamal Manoly Engineering Program Branch Division of Engineering & Technical Programs Region I Mark Hartzman Fechanical Engineering Branch Division of Engineering
SUBJECT:
BRIEFING ON ACTIVITIES RELATED TO LICENSE CONDITIONS #1
&7 This sumary covers activities related to L.C. #1 and #7 starting with the meeting between the staff and PG&E on May 9th at NRR office:
1.
Staff concerns regarding PG8E letter DCL-84-164 of April 27, 1984 was presented in the meeting on May 9th.
The concerns included 12
, items (Attachment A). Of those, 6 items were resolved in the above meeting. The specific items resolved are:
Item 1:
Inclusion of the technical topics in L.C. #7 for review of all S/B computer analyzed pipe supports.
PG&E agreed to the review of the other 50% of the pipe e
supports packages which started prior to April 27, for incorporation of L.C. #7 technical topics after com-pletion of the 50% which started after April 27.
Item 3:
Instruction to reviewers to include the review of the-origin and the transmittal of. loads from pipe stress in the pipe support group.
PG&E check list for review of S/B supports covers the e
above concern adequately, since the load directions are based on the generic assumption in all pipe stress analysis which assigns a -ve. x-axis to the North direction.
Item 5:
Clarification regarding the definition of loads from pipe stress when integral attachments are utilized.
PG&E indicated that when integral attachment (trunions) e pep. Q)h~
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. JUN 7 584 are included in the analysis, the loads from the stress group will be provided at the corresponding node on the trunion.
Item 9:
Inclusion of frictional loads in the check list for review of pipe. supports.
.e PG&E indicated that they are included in M-9, which is considered adequate.
Item 10:
The technical basis for attachments No. 6, 7 & 8 of Instruction #55.
e The attachments are based on technical papers from Bethlehem Steel and U.S. Steel.
Item'11:
The method for combining warping normal and shear stresses due to torsion to those due to flexural stresses.
e PG&E presented the method they adopted for combining the above stress'.
In response to those items PG&E has issued Instruction I-59 which includes instructions for the evaluation and implementation of Licensing Coadition No. 7 concerns.
Other items of concern were resolved in the follow-up' audits at the PG&E office in S.F. on May 15-17, 1984 and May 29-June 1, 1984.
These specific issues are:
Item 2:
Inclusion of relevant Licensing Condition #7 concerns in S/B & L/B design criteria.
e PG&E has committed to the inclusion of L.C. #7 in the review of all S/B supports. With regard to L/B sup-ports, PG&E proposed the review of 200 calculations from a total population of 3668 packages, based on a statistical approach. The proposal was later presented in PG&E letter No. DCL-84-190 of May 18,1984. PG&E's statistical approach indicates that if a randomly selected sample of 200 is found to meet the project criteria, then there is greater than 99% confidence level that the remainder of the calculation packages will also meet the criteria.
At the conclusion of the last audit approximately 150 S/B packages were reviewed and found to meet the stress criteria.
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Item 4:
Check list for computer analyzed flexible and rigid baseplates.
PG&E attachment #2 of I-55 (items 17,18,19) addresses e
i the concern. Further clarification was added to revision #2 of-I-55 incorporating the staff's concerns, with regard to the verification of baseplate stresses and bolt interaction criteria.
Item 6:
Screening criteria for natural frequency o
PG&E response in the May 9th meeting did not adequately 1
address the staff's concerns.
In the first audit the staff position regarding more explicit criteria for 4
determining the proper dominant support frequency was addressed in a specific guideline for reviewing stiff-i ness of pipe supports.
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. Item 7:
Guidelines for computing the tributary pipe mass in a
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natural frequency calculation.
-l The guidelines were presented in May 9th meeting in e
Bethesda and in more detail at the first audit in S.F.
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The tributary pipe mass is generated in the pipe stress' i
analysis using the computer code ME 101. The technical j
details were considered acceptable by the staff.
.' Item 8:
The basis of the generic qualification of lug induced j
local pipe stresses.
e PG&E response was provided to the staff at the i
conclusion of first audit and finalized in a write-up which was provided in S.F. during the second audit.
The qualification for S/B support is based on the 4
selection of:
1.
ten highest combined load and pipe stress at lug locations; 2.
Nine calculations for i
highest computer analyzed themal pipe stress at lug locations; and finally 3.
Two specific calculations corresponding to the two identified lug location with effective axial pipe span larger than 100 ft.
The local stresses induced in the piping were computed 1
using WRC bulletin #107.
The qualification of stresses at the lug location was based on the ASME code case N-318.
i Item 12:
More explicit definition of significant warping.
I h
' JUN 7 1984 PG&E check list for STRUDL concerns and the specific e
t attachments in I-55 provide sets of curves which can be ~
used to quantify the effect of warping normal and shear stresses due to torsional moments.
If the magnitudes are found negl.igible, a statement is made by the designer to that effect.
II 2.
Additional activities and findings resulting from the two staff
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audits in S.F.
1.
At the conclusion of the second audit, PG8E had completed the review of 191 S/B support packages.
l 2.
i; PG8E provided a written response titled U-bolt allowables relating to concerns expressed regarding material ultimate s
stresses at high temperatures up to 650*F.
3.
Lateral torsional buckling of angle sections under axial j
loads.
1 PG&E included an additional check in I-55 regarding the width / thickness ratio.
The b/t limit of 12 is added to the screening criteria in instruction I-55 check list.
i 4.
~
Considerations of shear center location definition in STRUOL analysis of angle shapes was discussed in detail. Verifica-tion computer runs were performed to detemine the technical adequacy of STRUDL analysis when definition of shear center i
eccentricity'is included, j
PG&E prepared a write-up addressing the above concern, and the l
effect of ignoring shear center eccentricities in the struc-tural analysis of pipe supports. The effects were shown not i
to be significant.
1 5.
It was detennined from staff review of S/8 pipe support design i
packages, that a clear and uniform understanding of input in STRUDL analysis regarding the definition of cross section principal direction ()-angle) for angle sections was not apparent. PG8E was informed of this finding at the conclusion of the first audit.
Instruction I-58 was submitted by PG&E to j
provide a unifonn definition and specific direction for determir.ing this angle in STRUDL computer analysis.
1 6.
Specific instruction for the evaluation of L.C. #7 concerns was issued by PG&E (Instruction I-59) in response to staff request at the first audit in S.F.
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7.
Consideration of seismic self excitation of support structures is to be included in the evaluation for S/B and L/B pipe supports where significant. The evaluation need not be completed before ascension to full power.
PG&E was requested i
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to' provide the staff with proposed criteria and a completion date for addressing the above concern.
'8.
The latest revision of_ design criteria for pipe supports (M-9).
was found acceptable.
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9.
PG&E is to provide the staff with a listing of all L/B pipe supports reviewed for consideration of L.C. #7. The tabu-j lation will include percentages of warping nonnal and shear stresses to the total stresses and percentages to the corre-i sponding code allowable limits.
The response is required by l
June 6, 1984 l
- 10. A total of 21 small bore pipe support design packages were j
reviewed in both audits.
- 11. As a result of the staff review, discrepancies were identified
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where the PG&E reviewers did not document their judgements when reviewing site generated design packages.
The staff concluded that these discrepancies were insignifi-cant for the acceptability of the design effort.
j
. 12. Three errors were identified regarding considerations of p-angle and geometry input in stauot analysis of supports.
The effects were judged not to have a significant effect on the support adequacy.
- 13. PG&E has responded satisfactorily to Item f of LC #7 regarding tube steel dimensions, manufacturing processes, and size of l
l the weld effective throat in the submittal of Miy 18, 1984, j
and has been found to be acceptable.
i
- 14. Buckling criteria for 831.1 components. PG&E has changed their buckling criteria in DCM-M9 to satisfy the staff s
concerns, by reducing the allowable buckling load to that corresponding to AISC jurisdiction.
1 l
- 15. The staff has also reviewed the basis and documentation of a set of tables used by designers for quick verification of flexible baseplate adequacy.
No independent verification has been made but the basis for these tables appears reasonable.
These tables are therefore acceptable.
I'M
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l Kamal Manaly Mark Hartzman i
Engineering Program Branch Mechanical Engineering Branch Division of Engineering &
Division of Engineering
& Technical Prog ar.:
Region !
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R. Vollmer H. Schierling R. Bosnak B. Saffell I. Yin i
E. Sullivan j
R. Heishman i
- D' Allison l
J. Durr, Region I S. Ebneter, Region I 3
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Attachment 'A' Items of Concern Regarding Licensing Condition # 1 1.
. Inclusion of the technical topics in licensing condition f 7 is rdqu' ired for review of S/8 computer analyzed pipe supports.
(pg. 2 of enclosure 1) 2.
In Instruction I-55, the licensee should commit to inclusion of relevant licensing condition # 7 in S/B and L/B design criteria.
(pg. 2 of 9) 3.
Instructions (4.2) to reviewer shculd 11clude the review of the origin and transmittal of loads from pipe stress in pipe support group.
(pg. 3 of 9) 4.
Instructions 4.2 should include a check list for computer analyzed flexible and rigid base plates.
(pg. 3 of 9) 5.
Provide clarification for item 4.2.6(c)
(pg.6of9) also explain how the use of integral attachments by pipe support
. group is transmitted back to stress group.
' Indicate if i.! ere is a screening criteria for natural frequency 6.
calculation, and provide the basis.
(4.2.7 pg. 6 of 9) 7.
. Provide the guidelines for computing the tributary pipe mass in the natural frequency calculations for computer analyzed piping.
(4.2.7 pg,6of9)
' Provide the basis of the generic qualification of lug induced local 8.
' pipe stTesses.
(4.4.11 pg.7of9) 9.
Instructions 4.2.6 should include the review of frictional loads in the check list.
(pg.5of9) 10.
Provide the technical basis for attachments No. 6, 7 & 8 of instruction I-55.
11.
How are the warping normal and shear stresses due to torsion to be combined with those due to flexural stresses? Also indicate how St. Venant shear stresses are combined to other shear stresses.
(pg. 9 of 9) 12.
Explain the statement in item 4.5 (pg. 8 of 9) with regard to inclusion of warping stresses where warping is significant.
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