ML18038A553
| ML18038A553 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 03/18/1981 |
| From: | Dise D NIAGARA MOHAWK POWER CORP. |
| To: | Youngblood B Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8103240374 | |
| Download: ML18038A553 (22) | |
Text
I REGULATE INFORMATION DISTRIBUTION+'STEM (RIDS) e ACCESSION NBR e 8103240374 DOC, DATE 0 81/03/18 NOTARI2ED!
NO DOCKET e
FACIL:50-010 Nine Mile Point Nuc'lear Station, Unit 20 Niagara Moha 05000010 AUTH BYNAME AUTHOR AFFILIATION DISEUR D ~ P ~
Niagara Mohawk Power Corp.
RECIP NAME RECIPIENT AFFILIATION YOUNGBLOODEB,J, Licensing Branch 1
SUBJECT:
Forwards info provided at 810306 meeting w/NRC to discuss'nstaggored splices re DYNIDAG Threadbear Sys ~ Approval by 810331 requested to use sys in unstaggered applications subjt to described limitations 8 conditions.
DISTRIBUTION CODE:
0001S COPIESRECEIVED:LTR
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ENCL g SIZ 5:
TITLE". PSAR/FSAR AMDTS and Related Correspondence NOTES:
RECIPIENT ID CODE/NAME'CTION:
A/D LICENSNG RUSHBROOKFM ~
INTERNAL: ACCID EVAL BR26 CHEM ENG BR 08 CORE PERF BR 10 EMERG PREP 22;,
GEOSC IENCES 14 HYD/GEO BR 15 I 8 EI 06 LIC, QUAL BR MECH ENG BR 18 NRC PDR 02 OP LIC BR PROC/TST REV 20 S
BR22 IL 01 STRUCT G
BR25 COPIES LTTR ENCL 1
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0 1
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0 1
1 2
2 3
3 1
1 1
1 1
1 1
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1 1
1 1
RECIPIENT ID CODE/NAME YOUNGBLOODgB KIPERFKa 04 AUX SYS BR 07 CONT SYS BR 09 EFF TR SYS BR12 EQUIP QUAL BR13 HUM FACT ENG BR I8C SYS'R 16 LIC GUID BR MATL ENG BR 17 MPA OELD POWER SYS BR 19 QA BR 21 REAC SYS BR 23 SIT ANAL BR 24 SYS INTERAC BR COPIES LTTR ENCL 1
0 1
1 1
1 1
1 1
1 3
1 1
1 1
1 1
1 1
0 0
1 1
1 1
1 1
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TOTAL NUMBER OF COPIES REQUIREDe LTTR 57 ENCL 51
1
sf'IIASARA 0 MQog@%K NIAGARAMOHAWKPOWER CORPORATION/300 ERIE BOULEVARDWEST, SYRACUSE, N.Y, 13202/TELEPHONE (315) 474-1511 March 18, 1981 Mr. B.J. Youngblood, Chief Licensing Branch No.
1 Division of Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C.
20555 5
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Dear Mr. Youngblood:
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I.,
Re:
Nine Nile Point Unit 2 Docket No. 50-410 Enclosed are the handouts provided at the March 6, 1981 meeting with members of the Commission Staff to address unstaggered splices.
Your March 5, 1981 letter granted approval for the use of the DYWIDAG Threadbar System in staggered applications at Nine Mile Point Unit 2 provided the following conditions are met:
1)
Compliance with the applicable provisions of Section III, Division 2 of ASME Boiler and Pressure Vessel
- Code, 1980 Edition, including the Summer 1980 addenda; 2)
Compliance with the applicable provisions of Section 7.5 and 7.6 of ACI Code 349-76, "Code Requirements for Nuclear Safety Related Concrete Structures".
Additionally, Niagara Mohawk requests approval to utilize the DYWIDAG Threadbar System in unstaggered applications subject to the limitations and conditions described below:
1.
Compliance with the above referenced codes.
2.
Limited to bar sizes N6-Nll.
3.
4.
Limited to doweling at slab to wall junctions as typically shown in Sketch l.
The concrete design is in accordance with the strength method and allowable stresses as outlined in ACI-318-76 Code.
5 All seismic Class I reinforced concrete structures are designed I /I utilizing the load combinations for the operating design condition as specified in the Nine Mile Point Unit 2 Preliminary Safety Analysis Report Section 12.3.9.
For Nine Mile Point Unit 2, the rebar dowels at wall slab junction of seismic Class I structures are designed for the maximum moment achieved from the worst loading combination for the operating or design condition.
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M'arch 18, 1981 Page Two In case of unstaggered splices at wall slab junction for the Unit 2
- Project, the stress level in the dowels will be below 50Ã of the specified yield strength (as required by ACI-349) under all applicable load conditions (i.e., less than 20 ksi).
A typical design calculation showing the stress levels at wall slab junctions for two elevations in the Reactor Building is contained in the attached handouts from the March 6, 1981 meeting.
5.
The minimum spacing criteria for splices that will be used to avoid the formation of voids during concrete placement is also contained in the attached handouts from the March 6, 1981 meeting.
As requested at the March 6, 1981 meeting, 'ompares the elongation and strain of spliced vs unspliced bars at stress levels of 50K of the specified yield strength.
As shown by this table the elongation of a splice specimen is essentially identical with the elongation of the unspliced bar at this stress level.
The ACI 349-76 code assures that cracking in concrete due to slip in the splice is adequately controlled by:
l.
Demonstrating through qualification testing that the strain in the spliced specimen at 0.9 of the specified yield strength does not exceed that of an unspliced specimen by more than 50Ã.
2.
Limiting the maximum computed design load stress in the bar to less than 0.5 of the specified yield strength.
Therefore, Niagara Mohawk does not believe that group testing of unstaggered splices in concrete is necessary based on the commitment to comply with Sections 7.5 and 7.6 of ACI 349-76.
Based on the above, the approval for the limited use of the DYWIDAG Threadbar System in unstaggered splices as specified
- above, is requested by March 31, 1981.
Very truly yours, yg~ P Donald P. Disc Vice President Engineering
C
Niagara Mohawk Power Corporation Nine Mile Point Unit 2 Docket No. 50-410 Presentation DYWIDAG Threadbar Introduction Code Requirements Unstaggered Splices Statistical Summary Calculations
'I Spacing Criteria
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Use of DYNIDAG splices will comply with the requirements of ASME II Code, Division II and ACI 349.
Test results have shown that DYWIDAG splice meets the requirements for unstaggered splices:
1, Strain over length of the full connector at 90K yield is less than 150K of an unspliced bar.
2.
Maximum computed design load stress in spliced bar is less than
.5 fy.
3.
Splices develop at least 125K of the specified yield strength of bar in tension.
4
DYWIDAG Threadbar, grade 60 ksi, Splice System Statistical Summary of Elongation. in a Spliced Bar Specimen versus Elongation of an Unspliced. Bar Specimen at.90% of minimum required yield (54 ksi) 86:
Spliced Specimen Unspliced Specimen E in%
0.0245 0.0195 26 38 18 36 28 Elongation in 10 inch 0.0270 0.0230 0.0265 0.0250 0.0210 Average 0.0245 26 87.
Spliced Specimen Unspliced Specimen EinX 0.028 0.026 8.
0.022
-4 10 4
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'15 Elongation in 12 inch 0.025 0.0285 0.028 0.027 Average 0.0264
/18:
Spliced Specimen Unspliced Specimen E in%
0.037 0.028 32 20 30 18 14 Elongation in 14 inch 0.0335 0.0365 0.033 0.032 0.031 Average 0.0338 21 Spliced Unspliced E in Specimen Specimen O/
0.038 0.030 27 18 23 17 22 Elongation in 15 inch 0.0355 0.037 0.035 0.0365 0.039 30 Average 0.0368 23 f/10 Spliced Unspliced E in Specimen
.Specimen
%/
0.0485 0.035 39 34 33 41.
33 Elongation on 18 inch 0.047 0.0465 0.0495 0.0465 0.045 29 Average 0.0471 35 811 Spliced Specimen Unspliced Specimen EinX II14 Spliced Specimen Unspliced Specimen Ein%
0.0455 0.034 34 0.045 0.042 7
Elongation in 18 inch 0.0475 0.039 0.0415 0.046 40 15 22 35 19 21 20 18 Elongation in 22 inch 0.050 0.051 0.0505 0.0495 0.0395 16 0.050 19.
Average 0.0431 27 Average 0.0493 17 II18 Spliced Specimen Unspliced Specimen Ein%
0.0845 0.056 51 41 45 '6 51 46 Elongation in 30 inch 0.079 0.081 0.076 0.0845 0.082 CAverage 0.0812 45
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MINIMUM SPACING CRITERIA FOR SPLICES TO AVOID FORMATION OF VOIDS DURING CONCRETE PLACEMENT:
1.
THE CLEAR DISTANCE BETWEEN PARALLEL SPLICES IN A LAYER SHALL BE NOT LESS THAN THE NOMINAL DIAMETER OF THE BARS, NOR 1 IN.
2.
IN CASE OF COMPRESSION MEMBERS, THE CLEAR DISTANCE BETWEEN LONGITUDINAL SPLICES SHALL NOT BE LESS THAN ONE AND ONE HALF TIMES THE NOMINAL BAR DIAMETER, NOR 1 1/2 IN.
THE ABOVE CRITERIA IS IN COMPLIANCE WITH ACI-349-76.
FOR NINE MILE POINT UNIT 2, THE MINIMUM CLEAR DISTANCE BETWEEN PARALLEL SPLICES WILL NOT BE LESS THAN SIX TIMES THE NOMINAL DIAMETER OF THE BAR NOR 6 IN.
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ATTACHNENT 1
OYWIDAG Threadbar, Grade 60 ksi, Splice System Statistical Summary of Elongation in a Spliced Bar Specimen versus Elongation of an Unspliced Bar Specimen at 50 percent of minimum required yield (30 ksi)
No.
6 Spliced Specimen Unspliced Specimen Difference in 10 in, Difference in Strain (in./in.)
Elongation in 10 inch 0.010 0.011 0.008 0.011 0.001 0.0
-0.003 0.0001 0.0
-0.0003 0.010
-0.001
-0.0001
-0.001
-0.0001
-0.003
-0.0003 Average 0.010 0.008 0.0095
-0.0015
-0.00015 No.
7 Spliced Specimen Unspliced Specimen Difference in 12 in.
Difference in Strain (in./in.)
No.
8 Spliced Specimen Unspliced Specimen Difference in 14 in.
Difference in Strain (in./in.)
Elongation in 12 inch 0.012 0.012 0.013 0.015
-0.003
-0.003
-0.002
-0.00025
-0.00025
-0.00017 Elongation in 14 inch 0.013 0.012 0.013 0.017
-0.004
-0.005
-0.004
-0.00029
-0.00036
-0.00029 0.013
-0.002
-0.00017 0.012
-0.005
-0.00036 0.013
-0.002
-0.00017 0.012
-0.005
-0.00036 0.011
-0.004
-0.00033 0.012
-0.005
-0.00036 0.0123
-0.0027
-0.00023 0.0123 0.0047
-0.00034 No.
9 Spliced Specimen Unspliced Specimen Difference in 15 in.
Difference in Strain
( in./in. )
Elongation in 15 in.
0.017 0.017 0.017
- 0. 017 0.0 0.0 0.0 0.0 0.0 0.0 0.017 0.0 0.0 0.015 0.017
-0.002 0.0
-0.00013 0.0167
-0.0003
-0.00002 No.
10 Spliced Specimen Unspliced Specimen Difference in 18 in.
Difference in Strain (in./in)
Elongation in 18 inch 0.021 0.021 0.019 0.019
+0.002
+0.002 0.0
+0.0001
+0.00011 0.0
.- 0.022 0.020 0.020 0.0205
+0.003
+0.001
+0.001
+0.0015
+0.00017
+0.00006
+0.00006
+0.00008 No.
11 Spliced Specimen Unspliced Specimen Difference in 18 in.
Difference in Strain (in./in.)
0.019 0.019 0,0 0.0 Elongation in 18 inch 0.022 0.018 0.018 0.020 0.017
+0.003
-0.001
-0.001
+0.001
-0.002
+0.00017
-0.00006
-0.00006
+0.00006 0.00011 0.019 0.0 0.0 No.
14 Spliced Specimen Unspliced Specimen Difference in 22 in, Difference in Strain (in./in.)
Elongation in 0.020 0.021 0.023
-0.003
-0.002
-0.00014
-0.00009 22 inch 0.021
-0.002
-0.00009 0.023 0.0 0.0 0.021 0.022 0.0213
-0.002
-0.001
-0.0017
-0.00009
-0.00005
-0.00008 No.
18 Spliced Specimen Unspl iced Specimen Difference in 30 in.
Difference in Strain (in./in.)
Elongation in 0.033
'0.032 0.031
+0.002
+0.001
+0.00007
+0.00003 30 inch 0.031 0.0 0.0 0.029 0.033 0.031 0.0315
+0.0005
+0. 00002
-0.002
+0.002 0..0
-0.00007
+0.00007 0 o
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