ML20247J915
| ML20247J915 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 05/22/1989 |
| From: | NRC |
| To: | |
| Shared Package | |
| ML20247J920 | List: |
| References | |
| NUDOCS 8906010161 | |
| Download: ML20247J915 (6) | |
Text
O CONTAINMENT SYSTEMS SURVEILL/.NCE REQUIREMENTS (Continued) these requirements, a determination shall be made as to the cause of the occurrence and the_ tendon (s) shall be restored to the required level of integrity.
If the lift off force of the selected tendon lies below 90% of its Base Value, the tendon shall be completely detensioned and a determination made as to the cause of the occurrence.
b.
Determining that the average of the Normalized Lift Off Forces for each tendon group (vertical, dome and hoop) is greater than or equal to the minimum required average tendon force for the group.
The minimum required average tendon force is 1160 kips for vertical tendons,1063 kips for dome tendons, and 1000 kips for hoop tendons.
The Normalized Lift Off Force for a tendon is obtained by adding the Normalizing Factor appearing in Table 4.6-2 to the lift off force.
Failure to comply with this requirement may be evidence of aonormal degradation of the containment structure.
If the Normalized Lift-Off Force of any tendon is less than the applicable minimum required average tendon force, an investigation shall be conducted to determine the cause and extent of occurrence.
This investigation shall include as a minimum the measurement of lift-off forces of tendons adjacent to the deficient tendon to determine if the average of the tendon lift-off forces in this region of the containment is equal to or greater than the minimum required average tendon force.
Failure to comply with this requirement may be evidence of abnormal degradation of the containment structure.
c.
Detensioning one tendon in each group (dome, vertical and hoop) from the representative sample.
One wire shall be removed from each detensioned tendon and examined to determine:
1.
That over the entire length of the tendon wire, the wire has not undergone corrosion, cracks or damage to the extent that an abnormal condition is indicated.
2.
A minimum tensile strength value of 240,000 psi (guaranteed ultimate strength of the tendon material) for at least three wire samples (one from each end and one at mid-length) cut from each removed wire.
d.
Determining for each tendon in the above representative tendon sample, that an analysis of a sample of the sheathing filler grease is within the following limits:
1.
Grease Voids j 5% of net duct volume 2.
Sulphides 5 10 PPM 4.
Nitrates j 10 PPM 5.
Water Content 5 10% by weight SUMMER - UNIT 1 3/4 6-9 Amendment No. 76 8906010161 890522 f'DR ADOCK 05000395 PDC
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l PAGE INTENTIONALLY LEFT BLANK SUMMER - UNIT 1 3/4 6-10a Amendment No. 27, 76
PAGE INTENTIONALLY LEFT BLANK SUMMER - UNIT 1 3/4 6-10b Amendment No. 72, 76
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l SUMMER - UNIT 1 3/4 6-10c Amendment No. 22, 76 l
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e CONTAINMENT SYSTEMS BASES REACTOR BUILDING STRUCTURAL INTEGRITY (Continued)
In order for the tendon lift off force to be indicative of the level of prestress force in.the containment, each measured force must be adjusted for the known differences which exist among the tendons due to original stressing force and elastic-shortening loss.
This adjustment is accomplished through the use of a Normalizing Factor (NF.
whichresultsintheNormallz(t)).This factor is added to the lift off force, ed Lift Off Force.
The Normalizing Factor is given by:
NF (t) = {Fave( ) ~ f ( )} {1 b
}+AFfs I"
}
j i
{Fave( ) ~ f (o)} is the group average lock-off force at original stressing, i
minus the original stressing force for the specific tendon.
l I"
SR(t) is stress relaxation (percent) which occurs at time t after original stressing.
AF is the total elastic shortening tendon force loss.
n is the stressing sequence comprising the specific tendon.
N is the total number of stressing sequences for the group'of tendons which comprise the specific tendons.
i refers to the specific tendon.
t refers to the time after original stressing of the current inspection period.
The Base Values and Normalizing Factors of tendons selected for surveillance 4 through 10 are listed in Enclosure 8 of Attachment I to the Virgil C. Summer Nuclear Station Surveillance Test Procedure STP-160.001,
" Containment Tendon Test," Revision 2.
Based on experience from the first three tendon surveillance, STP-160.001 may have to be revised to add Base Values and Normalizing Factors for additional or alternate tendons not previsusly listed, but are required for a particular surveillance.
The res!sion level of STP-160.001, as listed above, need not be updated in this Technical Specification where a change to Enclosure 8 of Attachment I only adds Base Values and Normalizing Factors for tendons not previously listed, but were used as additional or alternates for a particular surveillance.
Base Values and Normalizing Factors listed in Enclosure 8 of Attachment I of STP-160.001 will not be revised prior to NRC approval.
The surveillance requirements for demonstrating the containment's structural integrity are in compliance with the recommendations'of Proposed Revision 3 to Regulatory Guide 1.35, " Inservice Inspection of Ungrouted Tendons in Prestressed Concrete Containments," April 1979, except that in place of the Lower Limit and 90% Lower Limit defined by these Regulatory Guides, the 95% Base Value and 90%
Base Value, respectively, are used.
SUMMER - UNIT 1 B 3/4 6-2a Amendment No. 76
N:. -.
l Mr.:0.:S. Bradham.
1 South Carolina Electric ~ & Gas Company
' Virgil C. Sunner Nuclear Station n
cc:
Mr. William A. Williams, Jr.
L iTechnical-Assistant - Nuclear Operations
~ Santee. Cooper P. 0.. Box 764 (Mail Code 153)
-Columbia, South Carolina 29218
'J..B. Knotts, Jr., Esq.
Bishop. Cook -Purcell and Reynolds L'
~1400 L Street, N.W.
Washington, D. C..
20005-3502 Resident Inspector / Summer NPS c/o U.S. Nuclear Regulatory Commission Route.1, Box 64-Jenkinsville, South Carolina 29065 Regional Administrator, Region II-
. U.S. Nuclear. Regulatory Connission, 101 Marietta Street, N.W., Suite 2900 Atlanta, Georgia 30323 Chairman, Frirfield County Council-P. O. Box 293 Winnsboro, South Carolina 29180
- Attorney General P. O. Box 11549 Columbia, South Carolina 29211
- Mr. Heyward G. Shealy, Chief Bureau of Radiological Health South Carolina Department of Health and Environmental Control 2600 Bull Street-
. Columbia, South Carolina 29201
- South Carolina Electric & Gas Company Mr. A. R.--Koon, Jr., Manager Nuclear Licensing Virgil C. Summer Nuclear Station P. O. Box 88 Jenkinsville, South. Carolina 29065 l