ML20005B020
| ML20005B020 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 06/29/1981 |
| From: | PORTLAND GENERAL ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML20005B016 | List: |
| References | |
| NUDOCS 8107060226 | |
| Download: ML20005B020 (3) | |
Text
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PLANT SYSTEMS 3/4.7.11 CONTROL BUILDING MODIFICATION CONNECTION BOLTS
- LIMITING CONDITION FOR OPERATION 3.7.11 The structural adequacy of the through-wall bolts used to tie rein-forced concrete and steel plate to the Control Building west and east walls shall be maintained at a level consistent with the acceptance criteria in Specification 4.7.11.1.
APPLICABILITY:
ALL MODES ACTION:
a.
With the structural adequacy of the bolts not conforming to the above requirements, restore the structural adeauacy of the bolts to within the limits within 14 days.
b.
If the structural adequacy of the bolts does not conform to the above requirements, report the degradation within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and prepare and submit a special report pursuant to Specification 6.9.2 within the next 10 days outlining the cause of the degradation and plans for restoring the structural adequacy of the bolts.
c.
The provisions of Specification 3.0.4 are not applicable.
SURVEILLANCE REQUIREMENTS 4.7.11.1 The structural adequacy of the through-wall bolts used to tie rein-forced concrete and steel plate to the Control Building west and east walls shall be demonstrated at the end of 6 months and 1, 3 and 5 years after initial tensioning and at 5-year intervals thereafter. Structural adequacy of the bolts shall be demonstrated by:
a.
Demonstrating that each bolt in a random and representative sample of not less than 25 percent of the total number of l
bolts has a tension equal to or greater than 80 percent of l
the initial bolt tension.
If the tension in any bolt is below 80 percent of the initial bolt tension, the tension in two adjacent bolts shall be measured.
If either of these bolts is found to have less than 80 percent of the initial bolt tension, then all bolts shall be tested. All bolts found to have less than 80 percent of the initial bolt tension shall be retensioned to the original installation l
tension value.
I
- This Technical Specification shall become effective upon initial tensioning of the connection bolts.
TROJAN-UNIT 1 3/4 7-37 eao7060226 810629 DR ADOCK 0500
PLANT SYSTEMS SURVEILLANCE REQUIREMENTS (Continued) b.
Demonstrating the acceptability of each test sample by showing that i-2a is greater than 0.8Xo, where i is the mean tension for that sample, o is the standard deviation, and Xo is the initial bolt tension.
If this criterion is not met, then all bolts shall be tested to the criteria in (a) above.
If the mean sample tension i is below 0.8Xo, the circumstances shall be reported pursuant to Technical Specification 6.9.1.8.i.
c.
Determining that there is no evidence of degradation or abnormal conditions by visual inspection while under tension for those bolts which are not removed of the condition of all bolts in the sample, their end anchorages and concrete or masonry in the vicinity of the anchorage.
In addition, 10 percent of the total number of bolts shall be removed and examined by a surface extsination technique for evidence of cracks or other abnormal degradation. The grease for these shall also be checked for presence, consistency, appear-ance and to assure that it is within its specification limits for water content.
If cracks or degradation are discovered in any one bolt (including condition of grease), two adjacent bolts (including grease) shall be examined.
If cracking or degradation is discovered in either of these two, then all i
bolts shall be examined.
Defective bolts or grease shall be replaced.
Abnormal degradation of the bolt or grease shall be reported pursuant to Technical Specification 6.9.1.8.i.
l d.
If the bolts inspected during the first four inspections meet the acceptance criteria of (b) snd (c), then the sample for the subsequent inspections may be reduced to not less than 10 percent of the total number of bolts for the testing required by Paragraph (a) and not less than 5 percent of the total number of bolts for that required by Paragraph (c).
Beginning with the third year inspection, a trend analysis e.
shall be used to predict the existing bolt tension at the end of the next inspection interval (2 years or 5 years l
thereafter).
If the predicted bolt tension is below.75 of the initial bolt tension (i-2a <.75Xo), this shall be considered as abnormal degradation and reported pursuant to Technical Specification 6.9.1.8.i.
f.
A detailed report of any abnormal degradation [as defined
~
in (b), (c) and (e) above] shall be submitted pursuant to Technical Specification 6.9.2 within 90 days after completion of the surveillance testing.
TROJ AN-UNIT 1 3/4 7-38
PLANT SYSTEMS SURVEILLANCE REQUIREMENTS (Continued) 4.7.11.2 To assure that the surveillance intervals for the first three inspections in Specification 4.7.11.1 are sufficient to maintain mean bolt tension above.75 of the initial bolt tension, the tension in a special sample group of 10 bolts (six in the west wall and four in the east wall-) shall be measured at 3-month intervals from initial tensioning. The tension values for the bolts in this special sample group shall be used to datermine the pattern of reduction in initial tension with time due to bolt relaxation and shrink /
creep of the concrete and grout.
Surveillance of the tension in this special sample group of bolts shall continue until tension reductions have stabilized or until the third year at which time the trend analysis of Specifica-tion 4.7.11.1.e shall govern.
If tension in any bolt in the special sample group falls below.8 of initial bolt tension, the circumstances shall be reported pursuant to Specification 6.9.1.8.i.
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