ML20042A720
| ML20042A720 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 03/15/1982 |
| From: | Schroeder C COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| REF-SSINS-6820 IEB-79-02, IEB-79-2, NUDOCS 8203230712 | |
| Download: ML20042A720 (32) | |
Text
_ _ _ _ _
Commonwealth Edison g
/
one First N: tion;l PI:n ChicTgo. Illinois
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1 Addidss~Riply'to" Post 0ffE.o Box 767
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y Chicago, Illinois 60690 March 15, 1982 p\\~
Gr N
Mr. James G. Keppler, Regional Adminis trato r 6
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' S 'l I
Directorate o f Inspection and s
Enforcement - Region III pp,9 a7.. t 7 I
d, p, plT'~ji U.S. Nuclear Regulatory Commission q(k 799 Roosevelt Road
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h >~yG<.
Glen Ellyn, IL 60137
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c>i
Subject:
LaSalle County Station Units 1 and 2 Final Report on Pipe Support Base Plate Design Using Concrete Expansion Anchor Bolts NRC Docket Nos. 50-373 and 50-374 Re ferences (a):
Cordell Reeo letter to J. Keppler dated Ju?y 5, 1979, Providing Response to I.E.Bulletin 79-02, Rev. 1.
(0):
D. Peoples letter to J.
Keppler dated December 7, 1979, Providing Response to I.E.Bulletin 79-02, Rev.
2.
(c):
E. D. Swartz letter to J. Keppler dated Augus t 26, 1981, Enclosing Summary Report Entitled " Static, Dynami c and Relaxation Testing o f Expansion Anchors."
Dear Mr. Keppler:
The purpose o f this letter is to transmit to you three (3) copies of the Final Report on Pipe Support Base Plate Designs Using Concrete Expansion Anchor Bolts for LaSalle County Station.
The final report is in response to NRC I.E.Bulletin 79-02, Revision 2, dated November 8, 1979, requiring all licensees and construction permit holders for nuclear power plants to review the design ano installation procedures for concrete expansion anchor bolts used in pipe support base plates in seismic Category I systems.
OhhOO3h3 PDR
}/AR 1 6 1982
'/t
t e
J.
G. Keppler March 15, 1982 If there are any further questions in this matter, please contact this office.
Very truly yours, t
3 f/6/82.
C.
W. Schroeder Nuclear Licensing Administrator im Fnclosures cc:
NRC Resident Inspector - LSCS Of fice o f Insp. & Enf. - Wash.
3633N
February 8, 1982 4
i FINAL REPORT ON PIPE SUPPORT BASE PLATE DESIGNS USING CONCRETE EXPANSION ANCHOR BOLTS (IN RESPONSE TO NRC IE BULLETIN 79-02, REV. 2 DATED NOV. 8, 1979)
LA SALLE COUNTY - UNITS 1 & 2
1.0 INTRODUCTION
This final report is in response to NRC IE Bulletin 79-02, Revision 2, dated November 8, 1979, requiring all licensees and construction permit holders for nuclear power plants to review the design and installation procedures for concrete expansion anchor bolts used in pipe support base plates in seismic category I systems.
1.1 PREVIOUS RESPONSES BY COMMONNEALTH EDISON COMPANY (CECO) TO NRC The following responses have been previously sent by CECO to NRC.
These responses will be referenced as required in this final report.
(a)
Cordell Reed letter to J. G. Keppler dated July 5, 1979, providing response to I.E Bulletin 79-02 Rev. 1.
(b)
D.
L.
People's letter to J. G. Keppler, dated December 7, 1979, providing response to IE Bulletin 79-02 Rev.
2.
(c)
E. Douglas Swartz letter to J. G. Keppler dated August 26,
- 1981, enclosing Summary Report entitled
" Static, Dynamic and Relaxation Testing of Expansion Anchors."
2.0 RESPONSE 'IO ACTION ITEMS Item I Verify that pipe support base plate flexibility was accounted for in the calculation of anchor bolt loads.
In lieu of supporting analysis justifying the assumption of i'
rigidity, the base plates should be considered flexible if the unstiffened distance between the member welded to the i
plate and the edge of the base plate is greater than twice the thickness of the plate.
It is recognized that this criterion is conservative.
Less conservative acceptance j
criterla must be justified and the justification submitted as part of the response to the Bulletin.
If the base plate is determined to be flexible, then recalculate the bolt loads using an appropriate analysis.
If possible, this is l
l i
- $n w
4 to be done prior to testing of anchor bolts.
These calcu-lated bolt loads are referred to hereafter as the bolt design loads.
A description of the analytical model used to verify that pipe support base plate flexibility is accounted for in the calculation of anchor-bolt loads is to be sub-mitted with your response to the Bulletin.
Response
Pipe support base plate flexibility has been accounted for in the calculation of expansion anchor bolt loads.
Our analytical work in the form of report, entitled " Evaluation of Analysis Procedures for the Design of Expansion Anchored Plates in Concrete" dated May 31, 1979, was sent to NRC per reference 1.1(a).
It has been shown in that report, that, when the flexibility of the expansion anchored base plate assembly, in conjunction with the load versus displacement behavior of the expansion anchor, is accounted for in a finite element solution, the " prying action" forces are largely relieved.
The results of our analytical work described above, are sub-stantiated by the results of flexible base plate tests per-formed under the direction of an independent testing laboratory.
Copies of our Summary Report of these tests were sent to NRC per Reference 1.l(c).
The results of these tests show that prying action is in the order of 15-20% of the applied load.
This increase in load due to prying action is lower than originally anticipated due to the lower stiffness modulus of expansion anchors installed in con-crete.
The effect of plate flexibility has been considered in the design of all pipe support base plates in LaSalle County Units 1&2.
Item 2 j
Verify that the concrete expansion anchor bolts have the following minimum factor of safety between the bolt design load and the bolt ultimate capacity determined from static load tests (e.g., anchor bolt manufacturer 's) which simulate the actual conditions of installation (i.e.,
type of con-I crete and its strength properties) :
a.
Four - For wedge and sleeve type anchor bolts, b.
Five - For shell type anchor bolts.
The bolt ultimate capacity should account for the ef fects of I
shear-tension interaction, minimum edge distance and proper bolt spacing.
If the minimum factor of safety of four for wedge type l
anchor bolts and five for shell type anchors cannot be shown then justification must be provided.
The Bulletin factors _ _ _ -
of safety were intended - for the maximum support load in-cluding the SSE.
The NRC has not yet been provided adequate justification that lower factors of safety are acceptable on a long term basis.
Lower factors of safety are allowed on an interim basis by the provisions of Supplement No. 1 to IE Bulletin No. 79-02.
The use of reduced factors of safety in the factored load approach of ACI 349-76 has not yet been accepted by the NRC.
Response
Wedge type expansion anchors have-been used exclusively in safety related areas for LaSalle County Units 1&2.
All ex-pansion anchored pipe base plate assemblies have been re-evaluated for a minimum factor of safety equal to 4.0 for the maximum support load including the SSE.
Existing expan-sion anchored pipe base plates have been modified if re-quired to provide a minimum factor of safety of 4.0.
The shear-tension interaction in the expansion anchors has been accounted for in the following manner:
In most cases, the total applied tension and shear is con-sidered to be carried by the expansion anchors in accordance with the following int'eraction equation:
5/3 5/3 (Tmax) f 1. 0
+
max where:
T=
Actual tension load in the anchor V=
Actual shear load in the anchor T""*
Allowable tension in the anchor
=
Allowable shear in the anchor V
=
In some cases, expansion anchored plate assemblies have been -
designed using a more conservative straight line interaction based on the shear friction concepts using a coefficient of friction to 0.7.
The resulting interaction equa-tion is: JL equal V
T + 0.7 d;Tmax or T F 1.4V 4 Tmax l
The straight line interaction approach !s considerably more conservative compared to the elliptical interaction formula t
i described above.
l Item 3 Describe the design requirements if applicable for anchor bolts to withstand cyclic loads (e.g.,
seismic loads and high cycle operating loads).
t l l
m s..
Response
The dynamic / cyclic loads for which the pipe support base plates have been designed are obtained either from a re-sponse spectrum or time history method of analysis, and therefore, properly account for any dynamic load consider-ation.
The concrete expansion anchor design allowables are based upon maintaining a minimum factor of safety 4.0 between the dynamic / cyclic design loads for OBE & SSE events and the bolt ultimate capacity.
Commonwealth Edison Company has completed a comprehensive dynamic test program to verify the dynamic behavior of ex-pansion anchors.
These tests verified that expansion anchors installed in reinforced concrete and in concrete block walls maintained a minimum factor of safety 4.0 under cyclic loading.
These tests also showed that preload is not a determining factor as far as capacity of the anchor is concerned.
Three (3) copies of our Summary Report entitled " Static, Dynamic and Relaxation Testing of Expansion Anchors in Response to NRC IE Bulletin 79-02" were sent to NRC per Reference 1.l(c).
Item 4 Verify from existing QC documentation that design require-ments have been met for each anchor bolt in the following areas:
(a)
Cyclic loads have been considered (e.g., anchor bolt preload is equal to or greater than bolt design load).
In the case of the shell type, assure that it is not in l
contact with the back of the support plate prior to preload testing.
(b)
Specified design size and type is correctly installed (e.g., proper embedmont depth).
If sufficient documentation does not exist, then initiate a l
testing program that will assure that minimum design requirements have been met with respect to sub-items (a) and (b) above.
A sampling technique is acceptable.
One accept-able technique is to randomly select and test one anchor l
bolt in each base plate (i.e.,
som7 supports may have more than one base plate).
The test should provide verificatien of sub-items (a) and (b) above.
If the test fails, all other bolts on that base plate should assure that each Seismic Category I system will perform its intended func-tion.
k Resoonse Wedge type expansion anchors have been used exclusively in safety related areas for LaSalle County Units 1 and 2.
Em-bedded lengths of both 4 1/2 anchor diameters and 8 anchor diameters have been used for the wedge type anchors.
All expansion anchors have been installed at LaSalle County Units 1 and 2 in accordance with approved QA/CC procedures.
These procedures require, as a minimum, verification of the following items:
(a)
Installation torque (b)
Test torque (a verification of proper installation torque)
(c)
Embedment length (d)
Anchor size The design of the expansion anchors for LaSalle County Units 1 and 2 has assured that the expansion anchor preload is greater than or equal to the design load.
However, the results of our tests described under Item 3 show that loss of preload in an anchor does not affect the static ultimate load capacity of the anchor, nor is preload required in an anchor to withstand cyclic loading.
Documentation of existing expansion anchor in-stallations at LaSalle County Units 1 and 2 is avail-able for review by NRC.
Item 5 Determine the extent that expansion anchor bolts were used in concrete block (masonry) walls to attach piping supports in Seismic Category 1 systems (or safety related systems as defined by Revision 1 of IE Bulletin No. 79-02).
If expan-sion anchor bolts were used in concrete block walls:
a.
Provide a list of the systems involved, with the number of
- supports, type of anchor
- bolt, line size, and whether these supports are accessible during normal plant operation.
b.
Desc.ibe in detail any design consideration used to account for this type of installation.
c.
Provide a detailed evaluation of the capability of the supports, including the anchor bolts, and block wall to meet the design loads.
The evaluation must describe how the allowable loads on anchor bolts in concrete block walls were determined and also what analytical i
~...
method was used to determine the integrity of the block walls under the imposed loads.
Also describe the acceptance criteria, including. the numerical values, used to perform
-this evaluation.
Review the j
deficiencies identified in the Information Notice on the pipe supports and walls at Trojan to determine if a similar situation exists at your facility with regard to supports using anchor bolts in concrete block ~ walls.
d.
Describe the results of testing of anchor bolts in con-crete block walls and your plans and schedule for any further action.
Response
a.
Our initial response to this Bulletin per Reference 1.1 (b) indicated that safety related pipe supports using expansion anchors have not been attached to con-crete masonry walls.
Presently, three HVAC sensing lines (OVE OlA, OVE O2A and OVE 04A), 3/8"9 and running in a 1 1/4"9 conduit have been allowed to be attached to a masonry wall at three points using thru bolts and not expansion anchors.
Other piping attachment to con-crete masonry walls basically involves non-safety,.
small bore Class-D piping (line size 21/2"9 and under) such as instrument air lines, HVAC and process sensing lines.
Piping supports may be allowed for attachment to masonry walls when no other feasible supporting structure is available in the vicinity.- In such cases, the-adequacy of both the masonry wall and the expansion anchored assembly, is reviewed before the attachment is approved.
The safety related pipe supports attached -to the masonry wall as described above are accessible during normal plant operation, b.
The use of expansion anchors in concrete masonry walls has been restricted to solid and grouted concrete masonry walls, and to the attachment of small loads, typically less than 500 pounds.
Items falling under this category, for example, are small bore piping, in-strumentation lines, conduits and electrical junction boxes.
Heavier loads have not been permitted to be attached to concrete masonry walls, nor have expansion anchors been used in hollow concrete masonry walls.
Items actually attached to concrete masonry walls have been verified by field survey, and a final load check has been conducted to assure the adequacy of the masonry walls to carry the applied loads.
c.
The allowable design loads for expansion anchors in concrete masonry walls have been determined by static tests conducted at various units currently under con-struction.
Also, tests have been performed under the direction of.an independent testing laboratory, as ex-plained in response to Item 1.
The anchors in these tests were installed in solid concrete masonry units and in the masonry mortar joints.
'1he allowable loads for expansion anchors installed in solid concrete masonry have, thereby, been established as approxi-mately one-half of the corresponding allowables in plain concrete.
The expansion anchors provide a mini-mum factor of safety equal to 4.0 against ultimate test loads for the maximum support load including the SSE after accounting for the ef fects of plate and anchor flexibility.
The following concrete masonry units are used at LaSalle County Units 1 and 2.
1.
Mansory Units - ASTM Cl45, Type N-1 blocks, having a minimum net compressive strength equal to 1800 psi.
2.
Mortar - ASTM C270, Type M, having a minimum com-pressive strength equal to 2500 psi at 28 days.
The concrete masonry walls have been designed using clastic techniques.
The allowable stresses in concrete masonry walls are in accordance with the National Con-crete Masonry Association (NCMA) specifications for non-reinforced concrete masonry.
These stresses are:
Allowable Stress Type M Mortar Shear 34 psi Tension in flexure 39 psi normal to bed joints l
Tension in flexure 78 psi parallel to bed joints These allowable stresses are based upon a factor of l
l safety equal to approximately 3.0 against ultimate l
stress.
l No overstress has been permitted for OBE load combination.
An overstress factor of 1.67 has been l
permitted tor SSE load combination.
l A complete description of the concrete masonry wall l
design criteria is provided in CECO's response to NRC IE Bulletin 80-11.
Commonwealth Edison Company has reviewed the
~
deficiencies identified in the information notice con-cerning the adequacy of concrete masonry walls to l
s support attached items at the Trojan Plant, and has determined that a similar situation does not exist at LaSalle County Units 1&2.
d.
Tests have been performed on the capacity of expansion anchors in concrete masonry walls on several plants currently under construction.
- Also, Commonwealth Edison Company had committed in response to this Bulletin to participate in a comprehensive static and dynamic test program to substantiate the behavior of expansion anchors in concrete masonry walls.
These tests have since been completed.
The tests showed that expansion anchor's installed in concrete masonry walls maintained a minimum factor of safety 4.0 under cyclic loading and that preload is not a determining factor as far as capacity of the anchor is concerned.
A summary report on these tests was sent to NRC per Reference 1.1(C).
Item 6 Determine the extent that pipe supports with expansion anchor bolts used structural steel shapes instead of base plates.
The systems and lines reviewed must be consistent with the criteria of IE Bulletin No. 79-02, Revision 1.
If expansion anchor bolts were used as described above, verify that the anchor bolt and structural steel shapes in these supports were included in the actions performed for the Bulletin.
If these supports cannot be verified to have been included in the Bulletin actions:
(a)
Provide a list of the systems involved, with the number of
- supports, type of anchor bolt, line
- size, and whether the supports are accessible during normal plant operation.
(b)
Provide a detailed evaluation of the adequacy of the anchor bolt design and installation.
The evaluation should address the assumed distribution of loads on the anchor bolts.
The evaluation can be based on the results of previous anchor bolt testing and/or analysis which substantiates operability of the affected system.
(c)
Describe your plans and schedule for any further action necessary to assure the affected systems meet Technical Specifications operability requirements in the event of an SSE.
Response
In LaSalle County Units 1 and 2,
the design of safety related pipe supports with expansion anchors generally in-volved the use of base plates.
In a few cases structural 4
- s steel shapes with expansion anchors are used instead of base plates, to support relatively light loads.
In all cases where this design is encountered, the entire support has been treated in accordance with the criteria set forth in this bulletin.
Item 7 For those licensees that have had no extended outages to perform the testing of the inaccessible anchor bolts, the testing of anchor bolts in accessible areas is expected to be completed by November 15, 1979.
The testing of the in-accessible anchor bolts should be completed by the next ex-tended outage.
For those licensees that have completed the anchor bolt testing in inaccessible areas, the testing in accessible areas should continue as rapidly as possible, but no longer than March 1, 1980.
The analysis for the Bulletin items covering base plate flexibility and factors of safety should be completed by November 15, 1979.
Provide a
schedule that details the completion dates for IE Bulletin No. 79-02, Revision 2, items 1, 2, and 4.
Response
Testing of installed expansion anchors at LaSalle Ceunty Units 1 and 2 is not required since documentation of expan-sion anchor installation with approved QA/QC procedures is available.
Item 8 Maintain documentation of any sampling inspection of anchor bolts required by item 4 on site and available for NRC in-spection.
All holders of operating licenses for power reactor facilities are requested to complete items 5, 6, and 7 vithin 30 days of the date of issuance of Revisicn No.
2.
Also describe any instances not previously reported, in which you did not meet the revised (R2) sections of items 2 and 4 and, if necessary, your plans and schedule for resolu-tion.
Report in writing within 30 days of the date of this revision
- issuance, to the Director of the appropriate Regional Office, completion of your review.
For action not l
yet complete, a final report is to be submitted upon com-pletion of your action.
A copy of your report (s) should be sent to the United States Nuclear Regulatory Commission, Office of Inspection and Enforcement, Division of Reactor Operationu Inspection, Washington, D.C.
20555.
These re-porting requirements do not preclude nor substitute for the l
applicable requirements to report as set forth in the regu-lations and license.
Resnonse Documentation of expansion anchor installation and verifi-cation is maintained onsite at LaSalle County Units 1 and 2 i
_9_
[
and is available for NRC Inspection.
Requirements of the revised (R2) sections of Items 2 and 4 have been met as noted in the response to these items in this report, l
Item 9 All holders of construction permits for power reactor faci-
)
lities are requested to complete Items 5 and G for installed pipe supports within 60 days of date of issuance of Revision 2.
For pipe supports which have not yet,been installed, document your action to ensure that Items 1 through 6 will be satisfied.
Maintain documentation of these actions on-site available for NRC inspection.
Report in writing within 60 days of date of issuance of Revision 2, to the director of the appropriate NRC Regional Of fice, completion of your review and describe any instances not previously reported in which you did not meet the revised (R2) sections of Items 2 and 4 and, if necessary, your plans and schedule for resolu-tion.
A copy of your report should be sent to the United States Nuclear Regulatory Commission, Office of Inspection and Enforcement, Division of Reactor Construction Inspection, Washington, D.C.
20555.
Response
No response is required.
3.0 CONCLUSION
As explained in the responses to individual items of the Bulletin in Section 2.0 of this report, the design and installation of all safety related pipe supports with expan-sion anchors, at LaSalle County Units 1&2, is in conformance with the requirements of NRC IE Bulletin 79-02, Rev.
2.
l l
I l l 1
February 8, 1982 FINAL REPORT ON PIPE SUPPORT BASE PLATE DESIGNS USING CONCRETE EXPANSION ANCHOR BOLTS (IN RESPONSE TO NRC IE BULLETIN 79-02, REV. 2 DATED NOV.
8',
1979)
LA SALLE COUNTY - UNITS 1 & 2
1.0 INTRODUCTION
This final report is in response to NRC IE Bulletin 79-02, Revision 2, dated November 8, 1979, requiring all licensees and construction permit holders for nuclear power plants to review the design and installation procedures for concrete expansion anchor bolts used in pipe support base plates in seismic category I systems.
1.1 PREVIOUS RESPONSES BY COMMONNEALTH EDISON COMPANY (CECO) TO NRC The following responses have been previously sent by CECO to NRC.
These responses will be referenced as required in this final report.
(a)
Cordell Reed letter to J. G. Keppler dated July 5, 1979, providing response to IE Bulletin 79-02 Rev. 1.
(b)
D.
L.
People's letter to J. G. Keppler, dated December 7, 1979, providing response to IE Bulletin 79-02 Rev.
2.
(c)
E. Douglas Swartz letter to J. G. Keppler dated August 26,
- 1981, enclosing Summary Report entitled
" Static, Dynamic and Relaxation Testing of Expansion Anchors."
2.0 RESPONSE TO ACTION ITEMS Item I Verify that pipe support base plate flexibility was accounted for in the calculation of anchor bolt loads.
In j
lieu of supporting analysis justifying the assumption of l
rigidity, the base plates should be considered flexible if the unstiffened distance between the member welded to the plate and the edge of the base plate is greater than twice the thickness of the plate.
It is recognized that this criterion is conservative.
Less conservative acceptance I
criteria must be justified and the justification submitted as part of the response to the Bulletin.
If the base plate is determined to be flexible, then recalculate the bolt loads using an appropriate analysis.
If possible, this is
- i
to be done prior to testing of anchor bolts.
These calcu-lated bolt loads are referred to hereafter as the bolt design loads.
A description of the analytical model used to verify that pipe support base plate flexibility is accounted for in the calculation of anchor bolt leads is to be sub-mitted with your response to the Bulletin.
Response
Pipe support base plate flexibility has been accounted for in the calculation of expansion anchor bolt loads.
Oar analytical work in the form of report, entitled " Evaluation I
of Analysis Procedures for the Design of Expansion Anchored Plates in Concrete" dated May 31,-1979, was sont to NRC per reference 1.l(a).
It has been shown in that report, that, when the flexibility of the expansion anchored base plate
(
assembly, in conjunction with the load versus displacement behavior of the expansion anchor, is accounted for in a finite element solution, the " prying action" forces are largely relieved.
The results of our analytical work described above, are sub-stantiated by the results of flexible base plate tests per-formed under the direction of an independent testing laboratory.
Copies of our Summary Report of these tests were sent to NRC per Reference 1.l(c).
The results of these tests show that prying action is in the order of 15-20% of the applied load.
This increase in load due to prying action is lower than originally anticipated due to the lower stiffness modulus of expansion anchors installed in con-crete.
The effect of plate flexibility has been considered in the design of all pipe support base plates in LaSalle County Units 1&2.
Item 2
. Verify that the concrete expansion anchor bolts have the following minimum factor of safety between the bolt design load and the bolt ultimate capacity determined from static load tests (e.g., anchor bolt manuf acturer 's) which simulate the actual conditions of installation (i.e.,
type of con-crete and its strength properties) :
a.
Four - For wedge and sleeve type anc'or bolts, b.
Five - For shell type anchor bolts.
The bolt ultimate capacity should account for the ef fects of shear-tension interaction, minimum edge distance and proper bolt spacing.
If the minimum factor of safety of four for wedge type anchor bolts and five for shell type anchors cannot be shown then justificatica must be provided.
The Bulletin factors i
i of safety were intended for the maximum support load in-l cluding the SSE.
The NRC has not yet been provided adequate justification that lower factors of safety are acceptable on a long term basis.
Lower factors of safety are allowed on an interim basis by the provisions of Supplement No. 1 to IE Bulletin No. 79-02.
The use of reduced factors of safety in the factored load approach of ACI 349-76 has not yet been accepted by the NRC.
I
Response
Wedge type expansion anchors have-been used exclusively in safety related areas for LaSalle County Units 1&2.
All ex-pansion anchored pipe base plate assemblies have been re-evaluated for a minimum factor of safety equal to 4.0 for the maximum support load including the SSE.
Existing expan-sion anchored pipe base plates have been modified if re-quired to provide a minimum factor of safety of 4.0.
The shear-tension interaction in the expansion anchors has been accounted for in the-following manner:
In most cases, the total applied tension and shear is con-sidered to be carried by the expansion anchors in accordance with the following int'eraction equation:
5/3 5/3 max )f 1. 0 (fmax)
+
y where:
T=
Actual tension load in the anchor V=
Actual shear load in the anchor Allowable tension in the anchor T
=
V,ax m
Allowable shear in the anchor
=
x In some cases, expansion anchored plate assemblies have been designed using a more conservative straight line interaction based on the shear friction concepts using a coefficient of friction,4L equal to 0.7.
The resulting interaction equa-tion is:
V T + 0.7 d;Tmax or T& l. 4V d$ Tmax The straight line interaction approach is considerably more conservative compared to the elliptical interaction formula described above.
Item 3 Describe the design requirements if applicable for anchor bolts to withstand cyclic loads (e.g.,
seismic loads and high cycle operating loads). _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ - _
Response
The dynamic / cyclic loads for which the pipe support base plates have been designed are obtained either from a re-sponse spectrum or time history method of analysis, and therefore, properly account for any dynamic load consider-ation.
The concrete expansion anchor design allowables are based upon maintaining a minimum factor of safety 4.0 between the dynamic / cyclic design loads for OBE & SSE events and the bolt ultimate capacity.
Commonwealth Edison Company has completed a comprehensive dynamic test program to verify the dynamic behavior of ex-pansion anchors.
These tests verified that expansion anchors installed in reinforced concrete and in concrete block walls maintained a minimum factor of safety 4.0 under cyclic loading.
These tests also showed that preload is not a determining factor as far as capacity of the anchor is concerned.
Three (3) copies of our Summary Report entitled " Static, Dynamic and Relaxation Testing of Expansion Anchors in Response to NRC IE Bulletin 79-02" were sent to NRC per Reference 1.l(c).
Item 4 Verify f rom existing QC documentation that design require-ments have been met for each anchor bolt in the following areas:
(a)
Cyclic loads have been considered (e.g.,
anchor bolt preload is equal to or greater than bolt design load).
In the case of the shell type, assure that it is not in contact with the back of the support plate prior to preload testing.
i (b)
Specified design size and type is correctly installed i
(e.g., proper embedment depth).
If sufficient documentation does not exist, then initiate a testing program that will assure that minimum design requirements have been met with respect to sub-items (a) and i
I (b) above.
A sampling technique is acceptable.
One accept-l able technique is to randomly select and test one anchor l
bolt in each base plate (i.e., some supports may have more l
than one base plate).
The test should provide verification of sub-items (a) and (b) above.
If the test fails, all other bolts on that base plate should assure that each Seismic Category I system will perform its intended func-tion. l
i
~
Response
Wedge type expansion anchors have been used exclusively in safety related areas for LaSalle County Units 1 and 2.
Em-bedded lengths of both 4 1/2 anchor diameters and 8 anchor diameters have been used for the wedge type anchors.
All expansion anchors have been installed at LaSalle County Units 1 and 2 in accordance with approved QA/QC procedures.
These procedures require, as a minimum, verification of the following items:
(a)
Installation torque (b)
Test torque (a verification of proper installation torque)
(c)
Embedment length (d)
Anchor size The design of the expansion anchors for LaSalle County Units 1 and 2 has assured that the expansion anchor preload is greater than or equal to the design load.
However, the resu.lts of our te.mts described under Item 3 show that loss of preload in an anchor does not affect the static ultimate load capacity of the anchor, nor is preload required in an anchor to withstand cyclic loading.
Documentation of existing expansion anchor in-stallations at LaSalle County Units 1 and 2 is avail-able for review by NRC.
Item 5 Determine the extent that expansion anchor bolts were used in concrete block (masonry) walls to attach piping supports in Seismic Category 1 systems (or safety related systems as defined by Revision 1 of IE Bulletin No. 79-02).
If expan-sion anchor bolts were used in concrete block walls:
a.
Provide a list of the systems involved, with the number i
of supports, type of anchor bolt, line size, and whether these supports are accessible during normal plant operation.
t b.
Descr ibe in detail any design consideration used to account for this type of installation.
c.
Provide a detailed evaluation of the capability of the supports, including the anchor bolts, and block wall to meet the design loads.
The evaluation must describe how the allowable loads on anchor bolts in concrete block walls were determined and also what analytical method was used to determine the integrity of the block walls under the imposed loads.
Also describe the acceptance criteria, including the numerical values, used to perform this evaluation.
Review the deficiencies identified in the Information Notice on the pipe supports and walls at Trojan to determine if a similar situation exists at your facility with regard to supports using anchor bolts in concrete block walls.
d.
Describe the results of testing of anchor bolts in con-crete block walls and your plans and schedule for any further action.
Response
a.
Our initial response to this Bulletin per Reference 1.l(b) indicated that safety related pipe supports using expansion anchors have not been attached to con-crete masonry walls.
Presently, three HVAC sensing lines (OVE OlA, OVE O2A and OVE 04A), 3/8"# and running in a 1 1/4"9 conduit have been allowed to be attached to a masonry wall at three points using thru bolts and not expansion anchors.
Other piping attachment to con-crete masonry walls basically involves non-safety, small bore Class-D piping (line size 21/2"# and under) such as instrument air lines, HVAC and process sensing lines.
Piping supports may be allowed for attachment to masonry walls when no other feasible supporting structure is available in the vicinity.
In such cases, the adequacy of both the masonry wall and the expansion anchored assembly, is reviewed before the attachment is approved.
The safety related pipe supports attached to the masonry wall as described above are accessible during normal plant operation.
b.
The use of expansion anchors in concrete rhasonry walls has been restricted to solid and grouted concrete masonry walls, and to the attachment of small loads, typically less than 500 pounds.
Items falling under this category, for example, are small bore piping, in-atrumentation lines, conduits and electrical junction boxes.
Heavier loads have not been permitted to be attached to concrete masonry walls, nor have expansion anchors been used in hollow concrete masonry walls.
Items actually attached to concrete masonry walls have been verified by field survey, and a final load check has been conducted to assure the adequacy of the masonry walls to carry the applied loads.
c.
The allowable design loads for expansion anchors in l
concrete masonry walls have been determined by static t
l tects conducted at various unito currently under con-struction.
Also, tests have been performed under the direction of an independent testing laboratory, as ex-plained in response to Item 1.
The anchors in these tests were installed in solid concrete masonry units and in the masonry mortar joints.
The allowable loads for expansion anchors installed in solid concrete masonry have, thereby, been established as approxi-mately one-half of the corresponding allowables in plain concrete.
The expansion anchors provide a mini-mum factor of safety equal to 4.0 against ultimate test loads for the maximum support load including the SSE after accounting for the effects of plate and anchor flexibility.
The following concrete masonry units are used at LaSalle County Units 1 and 2.
1.
Mansory Units - ASTM C145, Type N-1 blocks, having a minimum net compressive strength equal to 1800 psi.
2.
Mortar - ASTM C270, Type M, having a minimum com-pressive strength equal to 2500 psi at 28 days.
The concrete masonry walls have been designed using clastic techniques.
The allowable stresses in concrete masonry walls are in accordance with the National Con-crete Masonry Association (NCMA) specifications for non-reinforced concrete masonry.
These stresses are:
Allowable Stress Type M Mortar Shear 34 psi Tension in flexure 39 psi normal to bed joints Tension in flexure 78 psi parallel to bed joints These allowable stresses are based upon a factor of safety equal to approximately 3.0 against ultimate stress.
No overstress has been permitted for OBE load combination.
An overstress factor of 1.67 has been permitted for SSE load combination.
A complete description of the concrete masonry wall design criteria is provided in CECO's response to NRC IE Bulletin 80-11.
i Commonwealth Edison Company has reviewed the deficiencies identified in the information notice con-cerning the adequacy of concrete masonry walls to I.
support attached items at the Trojan Plant, and has determined that a similar situation does not exist at LaSalle County Units 1&2.
d.
Tests have been performed on the capacity of expansion e
anchors in concrete masonry walls on several plants currently under construction.
- Also, Commonwealth Edison Company had committed in response to this Bulletin to participate in a comprehensive static and dynamic test program to substantiate the behavior of expansion anchors in concrete masonry walls.
These tests have since been completed.
The tests showed that expansion anchors installed in concrete masonry walls maintained a minimum factor of safety 4.0 under cyclic loading and that preload is not a determining factor as far as capacity of the anchor is concerned.
A summary report on these tests was sent to NRC per Reference 1.1 (C).
Item 6
~
Determine the extent that pipe supports with expansion anchor bolts used structural steel shapes instead of base plates.
The systems and lines reviewed must be consistent with the critoria of IE Bulletin No. 79-02, Revision 1.
If expansion anchor bolts were used as described above, verify that the anchor bolt and structural steel shapes in these supports were included in the actions performed for the Bulletin.
If these supports cannot be verified to have been included in the-Bulletin actions:
(a)
Provide a list of the systems involved, with the number of supports, type of anchor
- bolt, line size, and whether the supports are accessible during normal plant operation.
(b)
Provide a detailed evaluation of the adequacy of the anchor bolt design and installation.
The evaluation should address the assumed distributien of loads on the anchor bolts.
The evaluation can be based on the results of previous anchor bolt testing and/or analysis which substantiates operability of the affected system.
(c)
Describe your plans and schedule for any further action necessary to assure the affected systems meet Technical Specifications operability requirements in the event of an SSE.
Response
In LaSalle County Units 1 and 2,
the design of safety related pipe supports with expansion anchors generally in-volved the use of base plates.
In a few cases structural e
1 steel shapes with expansion anchors are used instead of bace plates, to support relatively light loads.
In all cases where this design is encountered, the entire support has been treated in accoriance with the criteria set forth in this bulletin.
Item 7 For those licensees that have had no extended outages to perform the testing of the inaccessible anchor bolts, the testing of anchor bolts in accessible areas is expected to be completed by November 15, 1979.
The testing of the in-accessible anchor bolts should be completed by the next ex-tended outage.
For those licensees that have completed the anchor bolt testing in inaccessible areas, the testing in accessible areas should continue as rapidly as possible, but no longer than March 1, 1980.
The analysis for the Bulletin items covering base plate flexibility and factors of safety should be completed by November 15, 1979.
Provide a
schedule that details the completion dates for IE Bulletin No. 79-02, Revision 2, items 1, 2, and 4.
Response
Testing of installed ' expansion anchors at LaSalle County Units 1 and 2 in not required since documentation of expan-sion anchor installation with approved QA/QC procedures is available.
Item 8 Maintain documentation of any sampling inspection of anchor bolts required by item 4 on site and available for NRC in-spection.
All holders of operating licenses for power reactor facilities are requested to complete items 5, 6, and 7 within 30 days of the date of issuance of Revision No. 2.
Also describe any instances not previously reported, in i
which you did not meet the revised (R2) sections of items 2 and 4 and, if necessary, your plans and schedule for resolu-tion.
Report in writing within 30 days of the date of this revision
- issuance, to the Director of the appropriate Regional Office, completion of your review.
For action not t
yet complete, a final report is to be submitted upon com-Pletion of your action.
A copy of your report (s) should be sent to the United States Nuclear Regulatory Commission, Office of Inspection and Enforcement, Division of Reactor Operations Inspection, Washington, D.C.
20555.
These re-(
porting requirements do not preclude nor substitute for the l
applicable requirements to report as set forth in the regu-lations and license.
i l
Response
Documentation of expansion anchor installation and verifi-cation is maintained onsite at LaSalle County Units l_and 2
_9-
and is available for NRC Inspection.
Requirements of the revised (R2) sections of Items 2 and 4 have been met as noted in the response to these items in this report.
Item 9 All holders of construction permits for power reactor faci-lities are requested to complete Items 5 and 6 for installed pipe supports within 60 days of date of issuance of Revision 2.
For pipe supports which have not yet been installed, document your action to ensure that Items 1 through 6 will be satisfied.
Maintain documentation of these actions on-site available for NRC inspection.
Report in writing within 60 days of date of issuance of Revision 2, to the director of the appropriate NRC Regional Office, completion of your review and describe any instances not previously reported in which you did not meet the revised (R2) sections of Items 2 and 4 and, if necessary, your plans and schedule for resolu-tion.
A copy of your report should be sent to the United States Nuclear Regulatory Commission, Office of Inspection and Enforcement, Division of Reactor Construction Inspection, Washington, D.C.
20555.
Response
No response is required.
3.0 CONCLUSION
As explained in the responses to individual items of the Bulletin in Section 2.0 of this report, the design and installation of all safety related pipe supports with expan-sion anchors, at LaSalle County Units 1&2, is in conformance with the requirements of NRC IE Bulletin 79-02, Rev.
2.
~
l l
l l
f
__ l
- /,'
M February 8, 1982 I
FINAL REPORT ON PIPE SUPPORT BASE PLATE DESIGNS USING CONCRETE EXPANSION ANCHOR BOLTS (IN RESPONSE TO'NRC IE BULLETIN 79-02, REV. 2 DATED NOV. 8, 1979)
LA SALLE COUNTY - UNITS 1 & 2
1.0 INTRODUCTION
This final report is in response _to NRC IE Bulletin 79-02, Revision 2, dated November 8, 1979, requiring all licensees and construction permit holders for nuclear power plants to review the design and installation procedures for concrete expansion anchor bolts used in pipe support base plates in seismic category I systems.
1.1 PREVIOUS RESPONSES BY COMMONNEALTH EDISON COMPANY (CECO) TO NRC The following responses have been previously sent by CECO to NRC.
These responses will be referenced as required in this final report.
(a)
Cordell Reed letter to J. G. Keppler dated July 5, 1979, providing response to IE Bulletin 79-02 Rev.
1.
(b)
D.
L.
People's letter to J. G. Keppler, dated December 7, 1979, providing response to IE Bulletin 79-02 Rev.
2.
(c)
E. Douglas Swartz letter to J. G. Keppler dated August 26,
- 1981, enclosing Summary Report entitled
" Static, Dynamic and Relaxation Testing of Expansion Anchors."
2.0 RESPONSE TO ACTION ITEMS Item I Verify that pipe support base plate flexibility was accounted for in the calculation of anchor bolt loads.
In lieu of supporting analysis justifying the assumption of rigidity, the base plates should be considered flexible if the unstiffened distance between the member welded to the plate and the edge of the base plate is greater than twice the thickness of the plate.
It is recognized that this criterion is conservative.
Less conservative acceptance criteria must be justified and the justification submitted as part of the response to the Bulletin.
If the base plate is determined to be flexible, then recalculate the bolt loads using an appropriate analysis.
If possible, this is
' ' !: ' ll to be done prior to testing of anchor bolts.
These calcu-lated bolt loads are referred to hereafter as the bolt design loads.
A description of the analytical model used to verify that pipe support base plate flexibility is accounted for in the calculation of anchor bolt loads is to be sub-mitted with your response to the Bulletin.
Response
Pipe support base plate flexibility has been accounted for in the calculation of expansion anchor bolt loads.
Our analytical work in the form of report, entitled " Evaluation of Analysis Procedures for the Design of Expansion Anchored Plates in Concrete" dated May 31, 1979, was sent to NRC per reference 1.l(a).
It has been shown in that report, that, when the flexibility of the expansion anchored base plate assembly, in conjunction with the load versus displacement behavior of the expansion anchor, is accounted for in a finite element solution, the " prying action" forces are largely relieved.
The results of our analytical work described above, are sub-stantiated by the results of flexible base plate tests per-formed under the direction of an independent testing laboratory.
Copies of our Summary Report of these tests were sent to NRC per Reference 1.l(c).
The results of these tests show that prying action is in the order of 15-20% of the applied load.
This increase in load due to prying action is lower than originally anticipated due to the lower stiffness modulus of expansion anchors installed in con-crete.
The ef fect of plate flexibility has been considered in the design of all pipe support base plates in LaSalle County Units 1&2.
~
Item 2 Verify that the concrete expansion anchor bolts have the following minimum factor of safety between the bolt design load and the bolt ultimate capacity determined from static load tests (e.g., anchor bolt manufacturer 's) which simulate the actual conditions of installation (i.e.,
type of con-cr~te and its strength properties) :
a.
Four - For wedge and sleeve type anchor bclts, b.
Five - For shell type anchor holts.
The bolt ultimate capacity should account for the ef fects of shear-tension interaction, minimum edge distance and proper bolt spacing.
If the minimum factor of safety of four for wedge type anchor bolts and five for shell type anchors cannot be shown then justification must be provided.
The Bulletin factors _ _
.l l
of safety were intended for the maximum support load in-cluding the SSE.
The NRC has not yet been provided adequate justification that. lower factors of safety are acceptable on a long term basis.
Lower factors of safety are allowed on an interim basis by the provisions of Supplement No. 1 to IE Bulletin No. 79-02.
The use of reduced factors of safety in the factored load approach of ACI 349-76 has not yet been acceptea by the NRC.
Response
Wedge type expansion anchors have been used exclusively in cafety related areas for LaSalle County Units 1&2.
All ex-pansion anchored pipe base plate assemblies have been re-evaluated for a minimum factor of safety equal to 4.0 for the maximum support load including the SSE.
Existing expan-sion anchored pipe base plates have been modified if re-quired to provide a minimum factor of safety of 4.0.
The shear-tension interaction in the expansion anchors has been accounted for in the following manner:
In most cases, the total applied tension and shear is con-sidered to be carried by the expansion anchors in accordance with the following int'eraction equation:
([ max)5/3 +(Ymax) f 1. 0 5/3 y
where:
T=
Actual tension load in the anchor V=
Actual shear load in the anchor T""*
Allowable tension in the anchar
=
V, x =
All wable shear in the anchor In some cases, expansion anchored plate assemblies have been designed using a more conservative straight line interaction based on the shear friction concepts using a coefficient of tion is:,4L equal to 0.7.
The resulting interaction equa-friction V
l T + 0.7 d;Tmax l
or T + 1.4V.C Tmax l
The straight line interaction approach is considerably more conservative compared to the elliptical interaction formula j
described above.
Item 3 Describe the design requirements if applicable for anchor i
bolts to withstand cyclic loads (e.g.,
seismic loads and I
high cycle operating loads). ---
Response
The dynamic / cyclic loads for which the pipe support base plates have been designed are obtained either f rom a re-sponse spectrum or time history method of analysis, and therefore, properly account for any dynamic load consider-ation.
The concrete expansion anchor design allowables are based upon maintaining a minimum factor of safety 4.0 between the dynamic / cyclic design loads for OBE Tx SSE events and the bolt ultimate capacity.
Commonwealth Edison Company has completed a comprehensive dynamic test program to verify the dynamic behavior of ex-pansion anchers.
These tests verified that expansion anchors installed in reinforced concrete and in concrete block walls maintained a minimum factor of safety 4.0 under cyclic loading.
These tests also showed that preload is not a determining factor as far as capacity of the anchor is concerned.
Three (3) copies of our Summary Report entitled " Static, Dynamic and Relaxation Testing of Expansion Anchors in Response to NRC IE Bulletin 79-02" were sent to NRC per Reference 1.l(c).
Item 4 Verify from existing QC documentation that design require-ments have been met for each anchor bolt in the following areas:
(a)
Cyclic loads have been considered (e.g.,
anchor bolt preload is equal to or greater than bolt design load).
~ ~ ~
~ -
In the case of the shell type, assure that i_t n not in contact with the back of the support plate pc to preload testing.
(b)
Specified design size and type is correctly installed (e.g., proper embedment depth).
If sufficient documentation does not exist, then initiate a testing program that will assure that minimum design requirements have been met with respect to sub-items (a) and (b) above.
A sampling technique is acceptable.
One accept-able technique is to randomly select and test one anchor bolt in each base plate (i.e.,
some supports may have more than one base plate).
The test should provide verification of sub-items (h) and (b) above.
If the test fails, all other bolts on that base plate should assure that each Seismic Category I system will perform its intended func-tion.
Response
Wedge type expansion anchors have been used exclusively in safety related areas for LaSalle County Units 1 and 2.
Em-bedded lengths of both 4 1/2 anchor diameters and 8 anchor diameters have been used for the wedge type anchors.
All expansion anchors have been installed at LaSalle County Units 1 and 2 in accordance with approved QA/QC procedures.
These procedures require, as a minimum, verification of the following items:
(a)
Installation torque (b)
Test torque (a verification of proper installation torque)
(c)
Embedment length (d)
Anchor size The design of the expansion anchors for LaSalle County Units 1 and 2 has assured that the expansion anchor preload is greater than or equal to the design load.
However, the results of our tests described under Item 3 show that loss of preload in an anchor does not affect the static ultimate load capacity of the anchor, nor is preload required in an anchor to withstand cyclic loading.
Documentation of existing expansion anchor in-stallations at LaSalle County Units 1 and 2 is avail-able for review by NRC.
Ite,m 5 Determine the extent that expansion anchor bolts were used in concrete block (masonry) walls to attach piping supports l
in Seismic Category 1 systemc (or safety related systems as defined by Revision 1 of IE Bulletin No. 79-02).
If expan-sion anchor bolts were used in concrete block walls:
l l
a.
Provide a list of the systems involved, with the number of
- supports, type of anchor
- bolt, line
- size, and whether these supports are accessible during normal plant operation.
b.
Describe in detail any design consideration used to account for this type of installation.
c.
Provide a detailed evaluation of the capability of the supports, including the anchor bolts, and block wall to meet the design loads.
The evaluation must describe how the allowable loads on anchor bolts in concrete block walls were determined and also what analytical t
i*
method was used to determine the integrity of the block walls under the imposed loads.
Also describe the acceptance criteria, including the numerical values, used to perform this evaluation.
Review the deficiencies identified in the Information Notice on the pipe supports and walls at Trojan to determine if a similar situation exists at your facility with regard to supports using anchor bolts in concrete block walls.
d.
Describe the results of testing of anchor bolts in con-crete block walls and your plans and schedule for any further action.
s
Response
d.
Our initial response to this Bulletin per Reference
- 1. l (b) indicated that safety related pipe supports using expansion anchors have not been attached to con-crete masonry walls.
Presently, three HVAC sensing lines (OVE 01 A, OVE O2A and OVE 04 A), 3/8"9 and running in a 1 1/4"9 conduit have been allowed to be attached to a masonry wall at three points using thru bolts and not expansion anchors.
Other piping attachment to con-crete masonry walls basically involves non-safety, small bore Class-D piping (line size 21/2"9 and under) such as instrument air lines, HVAC and process sensing lines.
Piping supports may be allowed for attachment to masonry walls when no other feasible supporting structure is available in the vicinity.
In such cases, the adequacy of both the masonry wall and the expansion anchored assembly, is reviewed before the attachment is approved.
The safety related pipe supports attached to the masonry wall as described above are accessible during normal plant operation.
b.
The use of expansion anchors in concrete masonry walls has been restricted to solid and grouted concrete masonry walls, and to the attachment of small loads, l
typically less than 500 pounds.
Items falling under j
this category, for example, are small bore piping, in-l strumentation lines, conduits and electrical junction boxes.
Heavier loads have not been permitted to be attached to concrete masonry walls, nor have expansion anchors been used in hollow concrete masonry walls.
Items actually attached to concrete masonry walls have been verified by field survey, and a final load check l
has been conducted to assure the adequacy of the masonry walls to carry the applied loads.
c.
The allowable design loads for expansion anchors in concrete masonry walls have been determined by static I
tests conducted at various units currently under con-struction.
Also, tests have been performed under the
. direction of an independent testing laboratory, as ex-plained in response to Item 1.
The anchors in these tests were installed in solid concrete masonry units and in the masonry mortar joints.
The allowable loads for expansion anchors installed in solid concrete masonry have, thereby, been established as approxi-mately one-half of the corresponding allowables in plain concrete.
The expansion anchors provide a mini-mum factor of safety equal to 4.0 against ultimate test loads for the maximum support load including the SSE after accounting for the effects of plate and anchor flexibility.
The following concrete masonry units are used at LaSalle County Units 1 and 2.
1.
Mansory Units - ASTM Cl45, Type N-1 blocks, having a minimum net compressive strength equal to 1800 psi.
2.
Mortar - ASTM C270, Type M, having a minimum com-pressive strength equal to 2500 psi at 28 days.
The concrete masonry valls have been designed using elastic techniques.
The allowable stresses in concrete masonry walls are in accordance with the National Con-crete Masonry Association (NCMA) specifications for non-reinforced concrete masonry.
These stresses are:
Allowable Stress Type M Mortar Shear 34 psi Tension in flexure 39 psi normal to bed joints Tension in flexure 78 psi parallel to bed joints These allowable stresses are basea upon a factor of safety equal to approximately 3.0 against ultimate stress.
l No overstress has been permitted for OBE load combination.
An overstress factor of 1.67 has been permitted for SSE load combination.
l A complete description of the concrete masonry wall design criteria is provided in CECO's response to NRC IE Bulletin 80-11.
Commonwealth Edison Company has reviewed the deficiencies identified in the information notice con-l cerning the adequacy of concrete masonry walls to 1
l l
-7_
l l
i.
T support attached items at the Trojan Plant, and has determined that a similar situation does not exist at LaSalle County Units 1&2.
d.
Tests have been performed on the capacity of expansion t
anchors in concrete masonry walls on several plants currently under construction.
- Also, Commonwealth Edison Company had committed in response to this Bulletin to participate in a comprehensive static and dynamic test program to substantiate the behavior of expansion anchors in concrete masonry walls.
These tests have since been completed.
The tests showed that expansion anchors installed in concrete masonry walls maintained a minimum factor of safety 4.0 under cyclic loading and that preload is not a determining f actor as far as capacity of the anchor is concerned.
A summary report on these tests was sent to NRC per Reference 1.l(C).
Item 6 Determine the extent that pipe supports with expansion anchor bolts used structural steel shapes instead of base plates.
The systems and lines reviewed must be consistent with the criteria of IE Bulletin No. 79-02, Revision 1.
If expansion anchor bolts were used as described above, verify that the anchor bolt and structural steel shapes in these supports were included in the actions performed for the Bulletin.
If these supports cannot be verified to have been included in the Bulletin actions:
(a)
Provide a list of the systems involved, with the number of
- supports, type of anchor
- bolt, line size, and whether the supports are accessible during normal plant operation.
(b)
Provide a detailed evaluation of the adequacy of the anchor bolt design and installation.
The evaluation should address the assumed distribution of loads on the anchor bolts.
The evaluation can be based on the results of previous anchor bolt testing and/or analysis which substantiates operability of the affected system.
(c)
Describe your plans and schedule for any further action necessary to assure the affected systems meet Technical Specifications operability requirements in the event of an SSE.
Response
In LaSalle County Units 1 and 2,
the design of safety related pipe supports with expansion anchors generally in-volved the use of base plates.
In a few cases structural -
steel shapes with expansion anchors are used instead of base plates, to support relatively light loads.
In all cases where this design is encountered, the entire support has been treated in accordance with the criteria set forth in this bulletin.
Item 7 For those licensees that have had no extended outages to perform the testing of the inaccessible anchor bolts, the testing of anchor bolts in accessible areas is expected to be completed by November 15, 1979.
The testing of the in-accessible anchor bolts should be completed by the next ex-tended outage.
For those licensees that have completed the anchor bolt testing in inaccessible areas, the testing in accessible areas should continue as rapidly as possible, but no longar than March 1, 1980.
The analysis for the Bulletin items covering base plate flexibility and factors of safety should be completed by November 15, 1979.
Provide a
schedule that details the completion dates for IE Bulletin No. 79-02, Revision 2, items 1, 2, and 4.
Response
Testing of installed expansion anchors at LaSalle County Units 1 and 2 is not required since documentation of expan-sion anchor installation with approved QA/QC procedures is available.
Item 8 Maintain documentation of any sampling inspection of anchor bolts required by item 4 on site and available for NRC in-spection.
All holders of operating licenses for power reactor facilities are requested to complete items 5, 6, and 7 within 30 days of the'date of issuance of Revision No. 2.
Also describe any instances not previously reported, in which you did not meet the revised (R2) sections of items 2 and 4 and, if necessary, your plans and schedule for resolu-tion.
Report in writing within 30 days of the date of this l
revision
- issuance, to the Director of the appropriate Regional Office, completion of your review.
For action not l
yet complete, a final report is to be submitted upon com-I pletion of your action.
A copy of your report (s) should be l
sent to the United States Nuclear Regulatory Commission, Office of Inspection and Enforcement, Division of Reactor Operations Inspection, Washington, D.C.
20555.
These re-porting requirements do not preclude nor substitute for the applicable requirements to report as set forth in the regu-l lations and license.
Response
l Documentation of expansion anchor installation and verifi-cation is maintained onsite at LaSalle County Units 1 and 2 I
r i
,*/e Q
g.. a and is available for NRC Inspection.
Requirements of the revised (R2) sections of Items 2 and 4 have been met as noted in the response to these items in this report.
i i
Item 9 All holders of construction permits for power reactor faci-lities are requested to complete Items 5 and 6 for installed pipe supports witbin.60 days of date of issuance of Revision 2.
For pipe supports which have not yet been installed, document your action to ensure that Items 1 through 6 will be satisfied.
Maintain documentation of these actions on-site available for NRC inspection.
Report in writing within 60 days of date of issuance of Revision 2, to the director of the appropriate NRC Regional Office, completion of your review and describe any instances not previously reported in which you did not meet the revised (R2) sections of Items 2 and 4 and, if necessary, your plans and schedule for resolu-tion.
A copy of your report should be sent to the United States Nuclear Regulatory Commission, Office of Inspection and Enforcement, Division of Reactor Construction Inspection, Washington, D.C.
20555.
Response
No response is required.
3.0 CONCLUSION
As explained in the responses to individual items of the Bulletin in Section 2.0 of this report, the design and installation of all safety related pipe supports with expan-sion anchors, at LaSalle County Units 1&2, is in conformance with the requirements of NRC IE Bulletin 79-02, Rev. 2.
l !
I o