Text

To Proposed Tech Spec 3.6.1.6 Re Containment Structural Integrity
	ML20053C644
Person / Time
Site:	Summer
Issue date:	05/26/1982
From:	; SOUTH CAROLINA ELECTRIC & GAS CO.
To:	;
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ML20053C643	List: ML20053C642; ML20053C644;
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	NUDOCS 8206020421
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CONTAINMENT SYSTEMS CONTAINMENT STRUCTURAL INTEGRITY LIMITING CONDITIONS FOR OPERATION 3.6.1.6 The structural integrity of the containment shall be maintained at a level consistent with the acceptance criteria in Specification 4.6.1.6.

APPLICABILITY: MODES 1, 2, 3 and 4.

ACTIION:

With the structural integrity of the containment not conforming to a.

the requirements of Specification 4.6.1.6.1.b, perform an engineer-ing evaluation of the containment to demonstrate the acceptability of containment tendons within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months ; otherwise, be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

b.

With the structural integrity of the containment otherwise not conforming to the requirements of Specification 4.6.1.6, in lieu of any other report required by Specification 6.9.1, prepare and submit a Special Report to the Commission pursuant to Specifica-tion 6.9.2 within 30 days after completion of the inspection describing the tendon condition, the condition of the concrete (especially at tendon anchorages), the inspection procedures, the tolerances on cracking, and the corrective actions taken.

SURVEILLANCE REQUIREMENTS 4.6.1.6.1 The structural integrity of the containment tendons shall be demon-strated at the end of one, three and five years following the initial containment structural integrity test and at five year intervals thereafter. The structural integrity of the tendons shall be demonstrated by:

Determining that for a representative sample

of at least 15 tendons a.

(4 dome 5 vertical and 6 hoop) each has a lif t off force greater than or equal to 95% of its Base Value indicated in Table 4.6-la.

If the lift off force of a selected tendon in a group lies between the 95%

Base Value and 90% of the Base Value, one tendon on each side of this tendon shall be checked for its lif t off force.

If the lift off 2

forces of the adjacent tendons are greater than or equal to 95% of their Base Values in Table 4.6-lb, the single deficiency shall be considered unique and acceptable.

For tendon (s) not conforming to

For each inspection, the ten

' hall be selected on a randon but representa-tive basis so that the samr e gtoue ill change somewhat for each inspection; however, to develop a history of teno,' performJnce and to correlate the observed data, one tendon from each grc.p (dome, vertical, and hoop) may be kept unchanged after the initial selection.

8206020421 820526 3/4 6-8 PDR ADOCK 05000395 A

PDR

CONTAINMENT SYSTEMS SURVEILLANCE 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 2

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 1

tendon group (vertical, dome and hoop) is greater than or equal to the minimum required average tendon force for the group.

The minimum re-quired average tendon force is 1195 kips for vertical tendons, 1115 kips for dome tendons, and 1181 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 abnormal degradation of the contain-ment 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 lif t-off forces of tendons adjacent to the deficient tendon to determine if the average of the tendon lift-off 1

forces in this region of the containment is equal to or greater than the minimum required average tendon force.

Failure to comply with this re-quirement may be evidence of abnormal degradation of the containment structure.

Detensioning one tendon in each group (dome, vertical and hoop) from the c.

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 cr damage to the extent that an abnormal condition is indicated.

2.

A minimum tensile strength value of 240,000 psi (guaranteed ulitmate 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

< 5% of net duct volume 2.

Chlorides 5 10 PPM 3.

Sulphides 5 10 PPM 4.

Nitrates

< 10 PPM 5.

Water Content

< 10% by weight 3/4 6-9

4 CONTAINMENT SYSTEMS SURVEILLANCE REQUIF'MENTS (Continued)

If the inspections performed at 1, 3, and 5 years indicate no abnormal degradation of the tendon system, the number of sample tendons may be reduced to 3 dome, 3 vertical, and 3 hoop for subsequent inspections. Upon the completion of the five year inspection, the results of the first three inspections shall be evaluated 1

to determine if an abnormal condition is evident for the tendon system. Based on the conclusions of this evaluation, the sample tendons with their Base Values 2

and Normalizing Factors will be specified for all subsequent inspections.

4.6.1.6.2 At the same inspection frequency as the tendons, the structural integrity of the end anchorages of all tendons inspected pursuant to Specification 4.6.1.6.1 and the adjacent concrete surfaces shall be determined by a visual inspection and verifying that no abnormal material or structural behavior is evident.

4.6.1.6.3 At the same inspection frequency as the Type A containment leakage rate test, the structural integrity of the exposed accessible interior and exterior surfaces of the containment shall be determined prior to each Type A containment leakage rate test (Specification 4.6.1.2) by a visual inspection of these surfaces and verifying that no abnormal material or structural behavior is evident.

3/4 6-10

4 3

TABLE 4.6-la BASE VALUE OF TENDON FORCE SURVEILLANCE TENDONS INSPECTION PERIOD 1

2 3

Tendon Base Value (kips)

D-104 1275 D-125 1230' D-108 1287

~

D-129 1245 D-219 1258 D-121 1225 D-219 1265 D-228 1275 D-219 1254 D-328 1287 D-324 1273

'D-312 1271 V-23 1328 V-23 1319 V-23 1313 V-46 1309 V-30 1287 V-37 1299 V-67 1332 V-53 1316 V-60 1294 V-92 1299 V-76 1315 V-83 1314 V-115 1322 V-99 1309 V-106 1296 3AC 1324 3AC 1313 3AC 1307 8BA 1272 13BA 1283 8CB 1254 13CB 1284 18CB 1264 18BA 1254 28CB 1263 28BA 1264 28AC 1261 38AC 1256 33CB 1282 33BA 1277 38BA 1253 36AC 1278' 38CB 1230 i

l l

i e

i (Rev. 2, 5/21/22)

TABLE 4.6-lb BASE VALUE OF TENDON FORCE J

ADJACENT TENDONS INSPECTION PERIOD 1

2 3

Tendon Base Value (kips)

D-1d3 1245' D-124 1284' D-107 1241 D-105 1250 D-126 1262 D-109 1222 D-128 1296 D-218

-1288 D-120 1284 D-130 1267 D-220 1291 D-122 1264 D-218 1296 D-227 1270 D-218 1281 D-220 1299 D-229 1235 D-220 1286 D-327 1244 D-323 1256 D-311

-1266 D-329 1237 D-325 1227 D-313 1237 V-22 1306 V-22 1300 V-22 1295 V-24 1320 V-24 1317 V-24 1313 V 1308~

V-29 1301 V-36 1284 V-47 1322 V-31 1327:

V-38 1293 V-66 1309 V-52 1316 V-59 1308 V-68 1309 V-54 1298 V-61 1309 U-91 1309 V-75 1304 V-82 1297 V-93 1327 V-77 1313 V-84 1311 V-114 1313 V-98 1280 V-105 1297 V-1 1320 V-100 1300 V-107 1307 2AC 1277 2AC 127G 2AC 1264 4AC 1264 4AC 1252 4AC 1245 7BA 1324 12BA 1267 7CB 1303 9BA 1292 14BA 1263 9CB 1284 12CB 1285 17CB 1271:

17BA 1261 14CB 1272 19CB

1287, 19BA 1289 27CB 1277j 27BA 1289 27AC 1297 29CB 1280 29BA 1272 29AC 1254 37AC 1283 32CB 1262 32BA 1259 39AC 1294 34CB 1232 34BA 1253 37BA 1294' 35AC 1297 37CB 1276 39BA 1273 37AC 1275 39CB 1291 s

(?ev. 2, 5/21/92)

TABLE 4.6-2 NORMELIZING FACTORS (N.F.)

INSPECTION PERIOD 1

2 3

Tendon N.F.

(kips)

Tendon N.F.

(kips)

Tendon N.F.

(kips)

D-304

-24 D-125 36 D-108

-42 D-129 33 D-219 10 D-121 40 D-219 10 D-228

-28 D-219 10 D-328

-21 D-324

-12 D-312

-20 V-23

-15 V-23

-15 V-46 11 V-30 31 V-37

-5 V-67

-21 V-53

-24 V-60 11 V-92 25 V-76

-11 V-83

-15 V-115

-10 V-99 5

V-106 7

3AC

-56 3AC

-56 8BA 18 13BA

-26 8CB 26 13CB

-23 18CB 29 18BA 34 28CB 26 28BA 17 28AC 10 38AC 40 33CB

-17 33BA

-16 38BA 40 36AC 0

38CB 54

/

~

(Rev. 1, 5/5/82)

CONTAINMENT SYSTEMS BASES 3/4.6.1.6 REACTOR BUILDING STRUCTURAL INTEGRITY This limitation ensures that the structural integrity of the containment will be maintained comparable to the original design standards for the life of the facility.

Structural integrity is required to ensure that the containment will withstand the maximum pressure of 47.1 psig in the event of a steam line break accident. The measurement of containment tendon lift off force, the tensile tests of the tendon wires, the visual examination of tendons, anchorages and exposed interior and exterior surfaces of the containment, and the Type A leakage --

test are sufficient to demonstrate this capability.

The tendon lif t off forces are evaluated to ensure that 1) the rate of tendon force loss is within predicted limits, and 2) a minimum required prestress level exists in the containment.

In order to assess the rate of force loss, the lift off force for a tendon is compared with the force predicted for the tendon times a reduction factor of 0.95.

This resulting force is referred to as the 95% Base Value. The predicted tendon force is equal to the original stressing force minus losses due to elastic shortening of the tendon, stress relaxation of 2

the tendon wires, and creep and shrinkage of the concrete. The 5% reduction on the predicted force is intended to compensate for both uncertainties in the prediction techniques for the losses and for inaccuracies in the lift-off force measurements.

In order for the tendon lift off force to be indicative of the level'of pre-stress 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 clastic shortening loss. This adjustment is accomplished through the use of a Normalizing Factor (NF (t)). This factor is added to the lift off force, which f

results in the Normalized Lift Off Force. The Normalizing Factor is given by:

(

NF (t) = {Fave(o) - F (o)} {l - 100 } + AF

{N - 2n + 1) i i

es 2N

{F ve( ) - F (o)} is the group average lock-off force at original stressing, f

minus the original stressing force for the specific tendon.

SR(t) is stresa relaxation (percent) which occurs at time t after original stressing.

T AF is the total clastic shortening tendon force loss.

es n is the stressing sequence comprising the specific tendon.

N is the total number of stressing sequences for the group of tendons l

which comprise the specific tendons.

i refers to the specific tendon.

t refers to the time after original stressing of the current inspection period.

l 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 B 3/4 6-2

CONTAINMENT SYSTEMS BASES (Continued)

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%

2 Base Value, respectively, are used.

O 9

B 3/4 6-3

1.35 INSERVICE INSPECTION OF UNGROUTED TENDONS IN PRESTRESSED CONCRETE CONTAINMENT STRUCTURES (Revision 3; 4/79) 17 s

The surveillance program for the Virgil C. Summer Nuclear Station containment prestressing system is in compliance with the recommendations of Regulatory Guide 1.35 with the following exceptions and clarifications:

A In place of the Lower Limit and 90% Lower Limit defined in this Guide, the 95% Base value and 90% Base Velue, respectively, are used. The Base Value is the force predicted for a tendon at_ the time of the surveillance. The Base Value is equal to the original stressing, force minus the losses described in Proposed Regulatory Guide 1.35.1, " Determining Prestressing Forces for 32 Inspection of Prestressed Concrete Containments," April 1979.

In the calcula-tion of the Base Value, zero tolerance has been applied to the losses. Ihh s

't,

d) losses are combined by considering t

raction of the tendon stress )

s s

relaxation and concrete creep using the procedure described in "A Method for Predicting Prestress Losses in a Prestressed Concrete Structure" which appeared in the Prestressed Concrete Institute Journal, March / April 1972.

The Surveillance program is discussed in Section 3.8.1 and 16.4.

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- AMENDMENT 32 JUNE, 1982 '

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ML20053C644

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