Text

Pcrv Tendon Interim Surveillance & Status Rept. W/Four Oversize Drawings
	ML20137M086
Person / Time
Site:	Fort Saint Vrain
Issue date:	01/31/1986
From:	; PUBLIC SERVICE CO. OF COLORADO
To:	;
Shared Package
ML20137M083	List: ML20137M079; ML20137M086;
References
	NUDOCS 8601280182
	Download: ML20137M086 (58)
	v • d • e

I I

PCRV TENDON g

INTERIM SURVEILLRNCE I

AND STATUS REPORT I

I

JANURRY, 1986 I

I E

1 I

I l

FORT ST.

VRRIN NUCLEAR GENERATING STRTION PUBLIC SERVICE COMPANY OF COLORRDO I

I I

I ger18a= 8 8aggy

I I

PCRV TENDON INTERIM SURVEILLANCE AND STATUS REPORT I

I January, 1986 E

I d

i FORT ST. VRAIN NUCLEAR GENERATING STATION 1

PUBLIC SERVICE COMPANY OF COLORADO

I l

R I

I ABSTRACT To comply with the requirements as set forth in the PCRV interim tendon surveillance program, a group of twelve control tendons have been identified for semiannual liftoff and/or visual surveillance.

The control tendons selected will remain the same through the remainder of the program.

In addition to the control tendon group, a group of forty-four "new" tendons were identified for visual surveillance during this first six-month interim surveillance period.

I The new-tendon group to be established for the next six-month period will consist of tendons other than those selected for the first six-month period.

As evidenced by the lack of an increase in the number of non-effective wires in any of the control tendons, it is concluded that an increase in the rate of tendon corrosion to a level of immediate concern has not occurred.

Liftoff results indicate that the load-ca rrying effectiveness of each of the control tendons is not showing any signs of relaxation or degradation from earlier liftoff surveillances.

In all cases, tendon loads measured to date are well above the minimum allowable tendon loads triggering mandatory engineering evaluation as specified in the most recent draft of the I

proposed Technical Specification for PCRV and Confinement Systems.

Increased monitoring of the twenty-seven load-cell-equipped tendons has also shown that all load values are sufficiently above the minimum allowable loads.

There is no indication in the thirty-one "new" tendons unich have had previous surveillances that the. rate of corrosion is accelerating; I

i.e.,

none of these new tendons have shown a significant increase in the number of non-effective wires or in the degree of corrosive degradation.

Supplemental surveillances on tendons other than those in the control or new tendon groups have further confirmed that there has been no accelerated wire breakage over the past twenty-two months of stepped-up surveillances.

The primary goal of remedial action being pursued to prevent further I

tendon corrosion is the elimination of the two most necessary ingredients for any type of corrosion: moisture and oxygen.

Prior to implementation of any long-term tendon corrosion solution on the PCRV it is intended to remove two existing PCRV tendons for the testing of proposed remedies in a tendon test facility remote from the reactor building. Two new tendons would replace those removed.

Preparations are under way for this initial removal / replacement operation.

The primary method being pursued at this time to achieve long-term I

tendon corrosion protection is the use of a bulk grease filler to fill the void space in the tendon duct thereby blocking the entrance of any moisture and oxygen. The grease currently under study for this use is a synthetic grease. Based on tests and analyses I

k

I performed to date, the synthetic grease is considered to be an excellent candida^te; however, acceptable grease consistency remains a I

problem to be resolved.

To improve monitoring of the load-carrying effectiveness of tendons I

currently not equipped with load cells, a prototype " split-shim" load cell assembly is being developed and will be tested. The use of a split-shim load cell would eliminate the need to replace a tendon in order to install a load cell.

For a period of three years or until such tirre as ef fective tendon corrosion control has been established, tendon interim surveillance will continue on the current semiannual basis.

I I

I E

I I

I

I CONTENTS I

1.0 INTRODUCTION

1 2.0 PCRV TENDON INTERIM SURVEILLANCE AND SUPPLEMENTAL......

2 SURVEILLANCE INFORMATION 2.1 REVIEW 0F TENDON INTERIM SURVEILLANCE REQUIREMENTS.......

2 2.2 REPORT OF FINDINGS OF THE FIRST SIX-MONTH INTERIM.......

5 SURVEILLANCE PERIOD 2.2.1 Visual Inspection.

5 2.2.2 Liftoff Testing...........

I6 2.3 SUPPLEMENTAL SURVEILLANCE INFORMATION.......

17 2.3.1 Tendons with Non-effective Wires..

. 17 2.3.2 Tendon Surveillance Historical Information.

. 20 2.3.3 Number and Percentage of Tendons Surveilled To Date. 22 2.3.4 Load Cell Surveillance..

. 22 2.3.5 Longitudinal Tendon Bottom-End Anchor Inspection... 32 3.0 TENDON CORROSION REMEDIAL MEASURES AND TENDON MONITORING.....

33 3.1 REVIEW AND STATUS OF PROPOSED TENDON CORROSION REMEDIAL...

33 1

MEASURES 3.1.1 Removal and Replacement of Two Existing Tendans..

34 for Test Purposes 3.1.2 Use of a Bulk Grease Filler for Long-Term Tendon... 37 I

Corrosion Protection 3.1.3 Nitrogen Blanket System for Tendon Corrosion.

. 44 Protection 3.2 TENDON MONITORING......................

48 3.2.1 Additional Tendon Load Cells.

48 3.2.2 Continued Tendon Surveillance...........

50 APPENDIX A:

PCRV TENDON SURVEILLANCE PLAN DRAWINGS..........

52 I

I

Page 1 of 52

1.0 INTRODUCTION

In ' March, 1985, a report entitled " Tendon Surveillance" I

was submitted to the Nuclear Regulatory Commission (NRC) under Public Service Company of Colorado (PSC) Cover Letter P-85084.

This report provided the following information:

1)

A general description of the Fort St. Vrain reactor vessel prestressing system; 2)

A summary of the tendon surveillance observations performed following original installation in 1970 through February 27, 1985; 3)

A description of the tendon corrosion and wire breakage problems observed; 4)

A report of the conclusive investigations and analyses performed to identify the cause of the corrosion based on the observations; 5)

A description of various remedial measures proposed I

to curtail the procession of corrosion, to prevent any new corrosion and to provide further monitors of tendon effectiveness and 6)

A description of informally proposed Technical Specification surveillance requirements and of an interim surveillance program to be implemented for a I

period of three years or until such time that effective corrosion control has been established.

The present report has been prepared to comply with the I

commitments of the interim surveillance program.

The interim surveillance program requires liftoff and/or visual surveillances to be performed on a given number of selected tendons over six-month intervals for the duration of the program.

The findings of these surveillances are to be reported to the NRC at the end of I

each six-month period. This report comes at the end of the first six-month interim surveillance period.

The implementation of the interim surveillance program was originally to have become effective April 22, 1985;

however, the effective date has since been changed to July 21, 1985, which corresponds with the first reactor restart following completion of the control rod drive refurbishment program (

Reference:

Attachment 1 of PSC Letter P-85199, dated June 14, 1985).

Some of the surveillances, however, to be included in the first six-month interim surveillance period were completed prior to July 21 in anticipation that the first six-month requirements would have to be met based on a start date of April 22. Because of this, this first "six-month" I

Page 2 of 52 interim surveillance period actually spans approximately eight months, from the first part of May, 1985 through the'beginning of January,1986.

In addition to reporting the findings of the required tendon surveillances for the first interim surveillance period, this report also provides an update on the status of proposed remedial measures to halt tendon corrosion, to deal with existing corrosion-caused effects and to improve the continuous monitoring of tendon effectiveness.

2.0 PCRV TENDON INTERIM SURVEILLANCE AND SUPPLEMENTAL SURVEILLANCE INFORMATION 2.1 REVIEW OF TENDON INTERIM SURVEILLANCE REQUIREMENTS The PCRV tendon interim surveillance program was fully described in the March, 1985 Tendon Surveillance Report.

A summarial review of the program requirements is presented here.

As stated in the Introduction, the interim surveillance program is to be in effect for a period of three years or

~

until such time that effective tendon corrosion control has been established and implemented.

The effective start date of the three year program is July 21, 1985, as discussed in the Introduction.

For the purposes of the interim surveillance program two types of surveillances are defined:

1)

Visual Inspection Visual inspection includes the removal of the tendon end cap and a visual examination of the inside of the cap, the cap o-ring seal and the visually-accessible portions of the tendon anchor assembly including tendon wire buttonheads, stressing washer, split shims and bearing plate for any signs of corrosion and degradation.

The number of non-I effective wires as indicated by raised or missing buttonheads is also to be noted.

Standard terminology has been defined and implemented into the tendon visual inspection surveillance procedures to describe any observed corrosion:

Discoloration:

Signifies the presence of any coloration which may have been caused by incipient corrosion.

i l

l 6

Page 3 of 52 I

Scaling:

Indicates the presence of rust-like deposits which tightly adhere to the surface.

Oxidation:

Indicates the presence of rust-like deposits which are heavy enough to I

indicate that they could flake off the surface.

2)

Liftoff Testing Liftoff

testing, in addition to the visual inspection as described above, also includes the measurement of tendon load by the use of a calibrated lif tof f jack, the removal and inspection of the split shims and a visual inspection of the I

tendon wire bundle accessed by the removal of the split shims.

Standard terminology to describe any observed I

corrosion as defined previously is also to be used for inspection during a lif toff test.

Under each of the two surveillance types described above, two types of tendon groups have been defined for the interim surveillance program:

1)

Control Tendon Group The control tendon group consists of a given I

population of tendons within each of the four tendon types (circumferential, top crosshead, bottom crosshead and longitudinal) which are to be selected I

at the beginning of the interim surveillance program and will remain the same for each pre-defined inspection / test cyclic period.

Selection of control tendons is based on the observance of corrosion on I

the tendon end anchor assembly or in the wire bundle prior to April 15, 1985.

2)

New Tendon Group The new tendon group consists of a given population of tendons selected at random each inspection / test period.

Selection shall be such that the total population of accessible tendons of each tendon type shall be inspected / tested before beginning any repeat inspections / tests.

l Within the scope and definitions of the two surveillance

g types and two tendon groups outlined above, the visual

g inspection and liftoff testing interim surveillance i

program requirements are as follows:

l r

,l

Page 4 of 52 l

1)

Visual Inspection Program Requirements

'The control tendon group shall consist of three(3)

I circumferential tendons (out of a total of 310 circumferential tendons), one (1) top crosshead tendon (out of 24 total), two (2) bottom crosshead I

tendons (out of 24 total) and six (6) longitudinal tendons (out of 90 total).

The selected control tendons.shall each be visually inspected during each of the six-month surveillance periods of the interim surveillance program.

The new tendon group shall consist of thirteen (13)

I circumferential tendons, one (1) top crosshead tendon, six (6) bottom crosshead tendons and twenty-four (24) longitudinal tendons. A new tendon group I

shall be randomly selected and visually inspected during each of the six-month interim surveillance periods.

Both ends of all designated control and new tendons shall be visually inspected, if accessible, except for the longitudinal tendons which may be inspected on the top end only.

2)

Liftoff Testing Program Requirements The control tendon group shall consist of three (3) circumferential tendons, one (1) top crosshead tendon, one (1) bottom crosshead tendon and three I

(3) longitudinal tendons.

These control tendons are to be included in the visual inspection control group.

In addition, one of these control tendons is to be a tendon equipped with a load cell.

The I

selected control tendons shall each be liftoff tested during each of the six-month interim surveillance periods.

The new tendon group shall consist of thirteen (13) circumferential tendons, one (1) top crosshead

tendon, three (3) bottom crosshead tendons and twelve (12) longitudirial tendons.

A new tendon group shall be randomly selected and liftoff tested during each eighteen-month surveillance period of I

the interim surveillance program. The new tendons selected for liftoff testing may be included in any new tendon group. selected for six-month visual inspections during the eighteen-month period.

Both ends of all designated control and new tendons shall be liftoff tested, if accessible, except for the longitudinal tendons which can only be liftoff tested on the top end.

Page 5 of 52 I

I 2.2 REPORT OF FINDINGS OF THE FIRST SIX-MONTH INTERIM SURVEILLANCE PERIOD 2.2.1 Visual Inspection 2.2.1.1 Control Tendons I

The control tendons selected for visual inspection are as follows:

Top Bottom Circumferential Crosshead Crosshead Longitudinal CM 1.1 TIRM2 BIRM4 VM-10 CO 14.4 BILM3 VI-20 CM 16.3 VM-20 l

VM-37 l

VI-40 VM-40 Each of the above control tendons was observed with at least some degree of rust or corrosion on the anchor assembly and/or in the wire bundle on at least one end l

prior to April 15, 1985.

Table 2.2-1 presents a complete historical surveillance information summary including the findings during this first six-month interim surveillance period of each end 1

of each control tendon.

Some of the historical l

surveillances are liftoff tests ("L") and some are visual

,I inspections only ("V").

The anchor assembly is inspected I

during both types of surveillances but the wire bundle I

can only be inspected during a lif toff test.

l The reported findings require special comment because they are not in all cases what one would expect to see.

l On many of the control tendons in which rust or corrosion was reported in the wire bundle prior to April 15,

1985, l

the more recent reports indicate that there was no discoloration observed in the wires.

The reason for this is that in the past whenever a liftoff test was performed on any tendon, following the inspection of the wire bundle, the wires were recoated with grease as prescribed by the liftoff procedure.

This has the effect of I

covering any existing corrosion with grease so that when a particular tendon is reinspected at a later date the previously observed corrosion may not again be visible.

It is believed, however, that if for some reason corrosion were accelerating at a more rapid pace than what has been generally observed in the past that this I

would become apparent by an increasing number of tendon wires observed as being non-effective from one inspection to the next.

If on the other hand new or continued wire b

E E

E Page 1 or 3 TABlf 2.2-1 C_0_fiJ ROL TENDONS ul HISTORICAL SURVEILLANCE INFORMATION

SUMMARY

Number or Tendon Sury.

Surv.

Non-Errective Liftorr Tendon No.

End(2)

Dato heilll Wirest41 load Ikipsi Co rros ion Cond i t ionl 51/Rema rks CH 1.1 1

10/15/85 L

0 1392 No disc. round on washer or wires.

Hold round on wires, i

10/02/84 L

0 1315 Lack or grease present. Rust visible throughout w8 re bundle.

Ill 10/17/85 L

0 1327 No disc. round on washer or wires, til 10/02/84 L

0 1275 Ve ry l i ttle g rease present. Rust visible throughout wire bundle.

CO 14.4 11 12/20/85 L

0 1237 No disc. on washer or wires. Wiret g rea sy, 11 10/17/84 L

0 1180 Some grease present. Rust present throughout wi re bund le.

VI 12/19/85 L

0 1196 No d i sc. on washer. No oxid, on wi res.

VI 10/17/84 L

0 1150 Lack or g rea se present. Rust visible throughout wi re area.

CM 16.3 111 12/13/85 L

0 1380 No disc. on washer or wires. Wires clean and greasy.

l11 03/25/85 L

0 1352 No rust on washer or wi res.

Medium grease on wi res.

V 12/16/85 L

0 1373 No d i sc. on wa she r.

Oxid, on both sides or wire bundle.

V 03/26/85 L

0 1368 No rust on washer. Rust and medium grease on both sides wire bundle.

TIRM2 lit-IV 12/18/85 L

0 1377 No disc. on washer or wi res.

Ill-IV 02/05/85 L

0 1364 No visible rust on washer or wires.

Oxid.

on shims inside surface.

VI-I 12/17/85 L

0 1380 No disc. on washer or wi res.

Wi res g rea sy.

VI-I 02/13/85 L

0 1370 No rust on washer. Rust and scale on shims.

Rust, scale and pitting on wires.

BIRM4 til-IV 12/30/85 L

0 1372 No d i sc. on wa sher or wi res.

y ill-IV 03/85 V

O Not reported.

n.

O ill-IV 09/11/8t4 L

N/R 1291 No rust round on wires. Wi res need g rea se.

lil-IV Of4/01/84 V

N/R B rg. plate and shims rusted.

(Load Cell)

VI-I 11/27/85 L

0 1344 No disc. on washer or wi res.

Load cell cn-liftorr value: 1257 kips, o

VI-I 03/85 V

O Not reported.

-g VI-I 09/11/84 L

N/R 1307 Rust present in wire bundle.

Lack or g rease p resent.

VI-I 04/01/84 V

N/R B rg. pla te corroded.

VI-I 12/71 V

N/R Co rroded.

M M

M Page 2 of 3 1A[}( Q 2-1 ( conLJ COMTROL TENDONSL1_1 HISTORICAL SujiyLLMNCE INFORMATION

SUMMARY

Tendon Surv.

Surv.

No failed Liftorr Corrosion Tendon No.

End(R)

Date T.ypot 3 )

Wires (4) load lkinsl Condition (Sl/ Remarks BILM3 fil-IV 01/03/86 L

0 1352 No di sc. on washer or wi res.

lil-IV 03/85 V

O Not re po r t ed.

Ill-IV 09/12/84 L

0 1287 Mold and rust present in wire bundle.

Lack or grease present.

+

lil-IV 04/01/84 V

N/R Brg, pla te rusted.

VI-I 12/03/85 L

1 1298 No di sc. on washer or wi res.

Greasy.

VI-I 03/85 V

1 Not reported.

VI-l 09/12/84 L

1 1279 Rust on tendon tube.

Wires well g rea sed.

Brg. plate and shims corroded.

VI-l 04/01/84 V

N/R VM-10 Top 06/20/85 L

7 1388 Disc. on brg, plate.

No disc. On washer.

Localized oxid. in wire bundle.

Top 01/17/85 V

7 No disc.

Top 04/09/84 L

3 1344 Not re po r ted.

Top 03/28/84 V

3 Condensation in cover.

VI-20 Top 06/21/85 L

0 1437 Washer, shims, brg. plate and accessible wi res in good condi tion.

Top 01/30/85 V

0 Not repo r ted.

Top 04/17/84 L

0 1443 Corrosion in interior of wire bundle.

Top 03/27/84 V

N/R No disc.

VM-20 Top 06/21/85 V

O Disc. on brg. plate.

-Top 01/30/85 V

O Not repo rted.

Top 04/17/84 L

0 1449 Corrosion in interior of wire bundle.

Top 03/27/84 V

N/R Dry spots.

VM-37 Top 06/19/85 V

1 Sca ling shims and brg. plate.

One ra ised btnhd. bent over.

Top 01/19/85 V

1 No disc.

i Top 04/09/84 L

1 1444 Corrosion on interior or I

wire bundle.

i' Top 03/28/84 V

1 Water in cover.

~

VI-40 Top 06/18/85 V

O No disc.

[

Not reported, ua Top 01/30/85 V

0 Top 04/19/84 L

0 1438 Corrosion in core or wi ro bundle.

Top 03/28/84 V

N/R Wa tor' in cover.

%a VM-40 Top 06/18/85 L

0 1437 Localized oxid, on wires in interior k

or bundle. No d i sc. on wa sher.

Top 01/30/85 V

O Not repo rted.

Top 04/19/84 L

0 1433 Loca lized corrosion in core or wire bundle.

Top 03/28/84 V

N/R Water in cover.

E E

Page 3 or 3 TABLE 2.?-1 (cont.)

COMIHOL TINQO_NSL11 HISTORICAL SURVfitLANCE INf0HMATION

SUMMARY

NOTES:

1) All cont ro l tendons except CO 14.4 have 169 original wires. CO 14.4 has 152 origina l wi res.

2, Irdicated by PCRV buttress number, ir between two buttresses, indicated by both nearest buttress numbers. Vertical tendons indicated by " top".

3) L: Lif tof f and visual inspection or anchor assembly and wi re bundle.

V: Visual inspection or anchor issembly only.

4) N/R: Not reported

5) Disc.: D i sco lo ra t ion Oxid.:

Oxidation Co r r. : Co rro s i on l

l l

e e

tc CD O

-b U1 FV m

Page 9 of 52 failure in the control tendons is not observed, this should indicate that corrosion is either no longer occurring or that it is occurring at such a slow rate I

that it does not present an immediate problem.

For these reasons it is believed that the control tendons are still useful as a representative monitor on the rate of any corrosion process occurring.

Based on the above line of reasoning and referring back to Table 2.2-1, no new non-effective wires have been observed in any of the control tendons during the latest round of surveillances compared with the earlier surveillances.

It can therefore be concluded that, to I

date, an increase in the rate of corrosion to a level of immediate concern has not occurred.

2.2.1.2 New Tendons j

{

The new tendons randomly selected for visual inspection for the first six-month interim surveillance period are as follows:

Top Bottom Circumferential Crosshead Crosshead Longitudinal CO 3.1 TILM2 BOLM4 VI-6 VI-22 CI 4.1 BOLL 3 VM-6 VM-22 CO 12.2 BORL3 VI-7 VI-28 CM 15.2 BIRL3 VM-7 VM-28 CI 16.2 BORM3 V0-7 V0-28 I

C0 4.3 BOLM4 VI-8 VI-29 CM 5.3 VM-8 VM-29 CO 8.3 VI-9 VI-36 CM 10.3 VM-9 VM-36 CI 4.4 VI-21 VI-38 C0 5.4 VM-21 VM-38 C

4 V0-21 VI-39 Table 2.2-2 presents the complete historical surveillance summary including the findings during this first six-month interim surveillance period of each end of each new tendon.

I The number of new tendons of each tendon type which have been observed at any time recently or before with at least some discoloration and/or corrosion on any of the I

anchor assembly parts or in the wire bundle on either end are as follows:

eight (8) out of thirteen (13) circumferential new tendons, zero (0) out of one (1) top crosshead new tendon, six (6) out of six (6) bottom crosshead new tendons and twelve (12) out of twenty-four (24) longitudinal new tendons.

I I

I

M M

M W

M M

M Page 1 of 6 JABLE 2.2-2 NEW TENDONSLU HISTORICAL SURVEll. LANCE INFORMATION

SUMMARY

Number of Tendon Sury.

Sury.

Non-Effective Liftoff Tendon No.

Fndf21 page Jype(3)

Wi re s t 4 )

load 1 k i ajd Corrosion Condit ionf 51/Rema rks CO 3.1 1

10/25/85 L

0 1389 No disc. on washer or wires. Wi res d ry.

Small amount of mold present.

(Load Cell) 111 10/31/85 L

0 1367 No disc. on washer.

Oxid. On a few vires.

1219 kips.

Load cell

=

Cl 4.1 1

10/30/85 L

0 1295 No disc. On washer or wires.

111 11/05/85 L

0 1259 Disc. on washer and shims.

Oxid.

On one wire, others no disc.

CO 12.2 IV 05/17/85 L

1 1195 No disc. on washer or wi res.

Medium g rea se.

VI 05/06/85 L

1 1205 No disc. on washer or wi res.

Little g rea se.

CM 15.2 IV 05/31/85 L

0 1233 No disc. on washer or wires.

VI 05/24/85 L

0 1243 No disc. on washer or wi res.

Little g rea se.

Cl 16.2 IV 06/13/85 L

0 1419 No disc. on washer or wires.

VI 06/13/85 L

0 1394 No d i sc. on wa she r.

Disc. On wires.

CO 4.3 til 08/30/85 L

0 1409 Oi sc. on wa she r.

No di sc. on wi res.

V 08/29/85 L

0 1341 No disc. on washer or wi res.

Ve ry l i tt l e grease.

CM 5.3 til 09/06/85 L

0 1258 No disc. On washer or wi res.

V 09/04/85 L

0 1239 No disc. on washer or wires.

CO 8.3 til 09/19/85 L

3 1184 No disc. on washer. Scaling on some wires.

Oxid, on shims.

(Load Cell)

V 09/20/85 L

0 1234 No disc. on waster.

Scaling on sample i

wire.

No other wire degradation noted.

i Load cell = 10,0.

T l

CM 10.3 Ill 10/02/85 L

0 1149 Di sc. On washe r.

Oxid, on shims.

l No degradation of wires noted.

(D l

V 10/0785 L

0 1215 No disc. On wa she r.

No degradation of

~

w e res noted.

o C1 4.4 II 08/19/85 L

0 1397 No disc. on washer or wi res.

$ j VI 08/22/85 L

0 1411 No disc. on washer or wires.

<.n FQ

4 m

M M

Page 2 or 6 LAJ!LE 2.2-2 (cont.)

Ntw TfNDOMS[1)

HISTORICAL SURVElLLANCE INFORMATION

SUMMARY

Number of Tendon Surv.

Surv.

Non-Errective Liftorr Tendon No.

fndf21 Datt e TypeL11 Wires (4) toad Ikins]

Corrosion Condit ionf 51/Rema rks CO 5.4 II 08/14/85 L

0 1250 0xid. on wa sher.

No disc. on wires.

VI 08/15/85 L

0 1192 No disc on washer or wires. Mold on tendon tube.

Cl 7.4 II 08/01/85 L

0 1242 No disc. on washer or wires.

(Load Cell)

Load cell = 1102 kips.

VI 08/06/85 L

0 1235 No disc. On washer or wires.

Cl 10.4 11 07/16/85 L

0 1176 0xid. on shim.

No disc. on washer or wares.

VI 07/24/85 L

0 1214 No disc. On washer or wires.

TILM2 til-IV 06/13/85 L

0 1373 No disc. on washer or wi res.

Wires heavily g rea sed,

lil-IV 02/12/85 L

0 1376 No rust on washer.

Interior wi res appea r dry.

VI-I 06/14/85 L

0 1363 No disc. on wa she r o r w i re s.

Wires heavily greased.

VI-I 02/12/85 L

0 1376 No rust on washer or wires.

BOLM4 til-IV 07/08/85 L

3 1310 No disc. on washer. Localized oxid. on

wires, til-IV 03/85 V

3 Not repo rted.

Ill-IV 09/17/84 L

N/R 1260 Welt g rea sed. No rust visible. One wire broke during liftorr.

lil-IV 04/01/84 V

2 B rg. plate rusted.

VI-I 07/08/85 L

0 1364 No disc. on washer or wires.

VI-l 03/85 V

O Not repo rted.

VI-I 09/17/84 L

N/R 1340 Well g rea sed. No rust visible.

VI-I 04/01/84 V

N/R Brg. plate peeling, d ry spots'.

BOLL 3 11-118 11/12/85 L

0 1358 No di sc. on wa sher.

Oxid. shims.

i Localized oxid. on wires.

Il-Ill 03/18/85 V

O Not repo r ted.11-111 04/01/84 V

N/R B rg. p la te, shims rusted.

n,3

~

V-VI 11/19/85 L

0 1437 No d i sc. on washer.

Localized oxid.

y on wires.

No grease on wires.

V-VI 03/18/85 V

O Not re po r ted.

l V-VI 04/01/84 V

N/R Loca lized corr, on brg, plate.

f C

BORL3 11-111 11/13/85 L

0 1411 No disc. on washer. Sca ling on wi res.

-h ll-111 03/18/85 V

0 Not repo rted.

tn 11-111 04/01/84 V

N/R Brg. pla te, shims rusted.

na V-VI 11/21/85 L

0 1401 No disc. washer. Localized oxid, on wi res.

V-VI 03/18/85 V

O Not repo rted.

V-VI 04/01/84 V

N/R Brg. pla te corroded, d ry spots.

m M

M M

Page 3 of 6 TABLE 2.2-2 (cont.)

NEW TENDO 3SL1]

HISTORICAL SURVEILLANCE INFORMATION

SUMMARY

Number of Tendon Surv.

Surv.

Non-Effective Liftoff Jypoill Wiresf4)

Load Ikipst Corrosion Condi t ionf 51/Rema rks Lendon No.

Endf2)

Date c

BIRL3 11-111 11/13/85 V

O No disc. On washer.14-111 03/18/85 V

O Not reported.11-111 04/01/84 V

N/R Brg pla te co rroded.

V-VI 11/21/85 L

0 1399 No di sc. On washer or wi res.

V-VI 03/18/85 V

O Not re po r ted.

V-VI 04/01/84 V

N/R Brg. plate, shims rusted.

BORH3 Ill-IV 01/02/86 L

0 1368 No d i sc. On wa she r o r wi re s, ill-IV 03/85 V

O Not reported.

ill-IV 09/04/84 L

N/R 1291 Scale on wi res and shims, lit-IV 04/01/84 V

N/R Scale.

VI-l 12/04/85 L

0 1335 No disc. On washer or wi res.

VI-I 03/85 V

O Not repo rt ed.

VI-I 09/04/84 L

N/R 1315 Scale on shims.

VI-l 04/01/84 V

N/R Scale.

BOLM4 til-IV 12/26/85 L

3 1340 No disc. On Washer or wi res.

IIl-IV 07/08/85 L

3 1310 No disc. on washer; oxid, on wi res, lil-IV 07/01/85 L

3 1310 No disc. on washer; oxid, on wires, lil-IV 03/85 V

3 Not repo rted,

lit-IV 09/17/84 L

N/R 1260 No rust.

lit-IV 04/01/84 V

2 Scale.

VI-I 12/02/85 L

0 1401 No disc. on washer or wires.

VI-I 07/08/85 L

0 1364-No disc.

VI-I 07/01/85 L

0 1372 No disc.

VI-l 03/85 V

0 Not repo r ted.

VI-I 09/17/84 L

N/R 1340 No rust.

VI-I 04/01/84 V

N/R Scale.

VI-6 Top 06/20/85 V

O Scaling on shims.

Not re po rted.

Top 01/22/85 V

0 Top 03/31/84 V

N/R No disc.

VM-6 Top 06/20/85 V

O No disc.

y Top 01/22/85 V

0 Not repo r ted,

n.

Top 04/13/84 L

0 1412 Corrosion in core of bundle.

C*

Top 03/31/84 V

N/R No disc.

e-.

P0 VI-7 Top 06/20/85 V

O No disc.

Top 01/22/85 V

O Not repo r ted,

o Top 04/12/84 L

0 1430 No visible corrosion.

Top 03/28/84 V

N/R No disc.

mru

M M

Page 4 or 6 TABLE 2.2-2 fcontd N[W TENDOML1)

HISTOHICAL SURVLlLLAfiCL INFORMATION

SUMMARY

Number of Tendon Surv.

Surv.

Non-Errective Liftoff Tendon No.

Endf2)

Date Type ( 3 )

Wiresf4) toad Ikiost Corrosion Condi t ionf 51/ftema rks VM-7 Top 06/20/85 V

O No disc.

Top 01/22/85 V

0 Not repo rted.

Top 04/13/84 L

0 1403 No visible corrosion.

Top 03/28/84 V

N/R Wa te r i n o i l. Condensation, corrosion in cover.

VO-7 Top 06/20/85 V

O Scaling on brg. plate.

Top 01/22/85 V

O Not reported.

Top 04/13/84 L

0 1398 No visible corrosion.

Top 03/28/84 V

N/R No disc.

VI-8 Top 06/20/85 V

O No disc.

Not repo r ted.

Top 01/17/85 V

0 Top 04/13/84 L

0 1438 No visible corrosion.

Top 03/28/84 V

N/R No disc.

VM-8 Top 06/20/85 V

4 Disc. on brg. plate.

Top 01/17/85 V

4 Not reported.

Top 04/19/84 L

3 1385 All vi sib le wi res.

No disc.

Top 03/28/84 V

3 Water, corrosion in cover.

VI-9 Top 06/20/85 V

O No disc.

Top 01/17/85 V

0 Not reported.

VM-9 Top 06/20/85 V

O Scaling in cap.

No d i sc. on anchor assembly.

Top 01/17/85 V

O Not repo rted.

Top 04/13/84 L

0 1451 Interior or wi re bundle corroded.

Top 03/23/84 V

N/R No disc.

VI-21 Top 06/21/85 V

O No disc.

Top 01/30/85 V

O Not repo rt ed.

i i

Top 04/17/84 L

0 1443 No visible corrosion.

I i

Top 03/29/84 V

N/R No disc.

,3 i

VM-21 Top 06/21/85 V

O D i sc. on b rg. plate.

j Top 01/30/85 V

0 Not re po rted.

Top 04/17/84 L

0 1422 No visible corrosion.

Top 03/29/84 V

N/R No disc.

O

-b VO-21 Top 06/21/85 V

O No disc.

Not reported.

on Top 01/30/85 V

O Top 04/17/84 L

0 1401 No visible corrosion.

PJ Top 03/29/84 V

N/R No disc.

Page 14 of 52 b

O I

e Om 4a I

a e

e e

x L

Q

=

m O

6 O

L G

b m

a C

O O

a -

E o

c >

E e

E a

O e

Q L

- 3 O

3 a

O O

e O

C a b O

O Z

a C L

c C

C C

O m

L m

C 6

L O

C 0

0 O

O

-LL.

M b

m C D -

L O

6 O

O L

e ego.

O e

D -

. O O

I O

6 bodX 0

O>Cd 0

W 4

W d

O 6

. O E

C O

V 6

Luso e g

L e

6 w

e..U u

o c.=

C b

.O

.O 3m E.

.O e.L

.m g

O O Vu VOC b

-VC VO

-UO VC

-VUU WVC C

O C

C

-00 CC-W CQU CO ESCO GO =

VW wg wg O

ww wg ww so wwwb Cw w

C a

6-w L-C L

LC 6-k.

Le LLL 06C C

L l

I E. odd

O40

.O COO

.OD.

COO

.OC

O COOO OO O

O j

404-0 Ua--Of 04-O a-U Ca' U a-O Caau Da-Oa0 W@Wa.W@ dedo

.Om WOde

.e3 de d

QQ CedC#

WQW O

--6-w 0-C 6O =

6u

-6m-

.66L

-6O-O >

L

-V V

>6Ve U

6 V

>V O

W V

EV O

c -

6VL V V E

b m

M 9

b Web d

ma-w-

mMu>

edLCL M

0 EOOOb C00000

~00 0000

-00 OOCO

-000 00030 000 E

O MZZZo ZZZUZZ oZO ZZZZ oZE ZZMZ oZZO MZU40 ZZZ ED M

Zo I

w H

4 E

W s

z c

I C

o b-i O

bx m

N N

c 2

O O

wZ 0-B 928 I I"8 8 I I I I tw I i8 8 0 020 8 8cl 8 80 8

I I I a

2 2

I w<

kV N

W

=m e

o.O JO N

Z;Z 1

N we j

a 6

3-I a

wa o E

=

r>

> I z

b-W 3

Ow-M o

Loe o com ococo occ ocoK oc% ocom ---" Coo E coK J

0w0 N

N N

N ab6 Z

Z Z

Z U-EW-

= e3 m

ZC o

O w

Z M

I Z

~

M

>w

>J>

>>J>>

>>J>

>>J bc

=

M I

e end cc22c ces ccan esa ccan cena ces 2 een I

e eme eeece ece come com come emme mee e mee i

N NNN NNNNN NNN NNNN NNN NNNN NNNN NNN N NNN

>t oNo

-oNo-

-ce

-ome

-ce

->cN

-5mN mom e moc I

be N men NmeNN NmN Nm-N NmN Ne~N Neon

~mo N emN Om N NNN NNNNN NNN NNNN NNN NNNN NNNN NNN N NNN Mo e enn Denmc cem mesm cem mesm c~2m men m mem o coo ococo coo occo oco coco occo oco o oco C-E I'

ON O

V-a CV a aOa anaad aaa aaaa aan aaan aaan ana a naa DC O

000 00000 000 0000 000 0000 0000 000 O

000 ww w www wwwwe www wwww www wwww wwww www w' www O.

Z C

O N

N e

e m

D V

N N

N M

m C

s e

e e

e t

I e

E E

o E

E I

M W

W Page 6 of 6 TABLE 2.2-2 (cont.1 MfWl fNDONS[1]

HISTORICAL SURVflLLANCE INFORMATION

SUMMARY

Number or Tendon Surv.

Surv.

Non-Errective Liftorf Tendon No.

End[?)

Date Jype[ll __ Wirest4) load Ikipst Corrosion Condi t ionf 51/Rema rks VI-38 Top 06/19/85 V

O No disc. on sample wire.

No disc.

Grease coverage good.

Top 01/30/85 V

O Not reported.

Top 04/09/84 L

0 1456 No visible corrosion in wires.

Top 03/28/84 V

N/R No disc.

(Load Cell)

Bottom 05/21/85 V

O No disc. No visible cracks. No water.

VM-38 Top 06/19/85 V

O No disc.

Top 01/22/85 V

O Not re po rt ed.

Top 04/09/84 L

0 1438 No disc. on visible wires.

Top 03/28/84 V

N/R No disc.

VI-39 Top 06/19/85 V

O No disc.

Top 01/30/85 V

0 Not re po r ted.

Top 04/19/84 L

0 1438 No visible corrosion.

Top 03/28/84 V

N/R No disc.

NOTES:

1) All new tendons have 169 original wi res except Cl 4.1, CO 12.2, CM 15.2, CM 5.3, CO 8.3, CM 10.3, CO 5.4, Cl 7.4 and Cl 10.4 which have 152 origina l wi res.

2) Indicated by PCRV buttress number, if between two buttresses, indicated by both nearest buttress numbers. Vertical tendons ind ica ted by " top" or " bottom".

3) L: Liftorr and visual inspection of anchor assembly and wire bundle.

V: Visual inspection of anchor assembly only.

4) N/R: Not reported.

5) Disc.: Di sco lo ra t i on Orid.:

Oxidation Co r r. : Co rros i on o,

u3 O

w UI O

U1 FQ i

i l

Page 16 of-52 I

Two (2) circumferential, one (1) bottom crosshead and two (2). longitudinal new tendons have been observed with at least one but not more than four non-effective wires.

Out of a total of forty-four (44) new tendons for visual inspection thirty-one (31) have had at least one I

surveillance prior to the start of the interim surveillance program.

Of these 31, there is no indication that the rate of corrosion is accelerating; i.e., none of these new tendons have shown a significant increase in the number of non-effective wires or in the degree of corrosive degradation when the new recent surveillances are compared to earlier surveillances.

The new-tendon observations show that the PCRV tendon corrosion problem is random in nature among the tendons I

of each of the different tendon types. No concentration of corroded tendons in any specific area of the PCRV has ever been observed. The observations of the new-tendon l

group have also shown that the circumferential tendon anchor assemblies and/or wires have been susceptible to at least some discoloration or corrosion although not to the degree observed and reported previously for the bottom crosshead and longitudinal tendonsa 2.2.2 Liftoff Testing 2.2.2.1 Control Tendons The control tendons selected for liftoff testing are as follows:

Top Bottom l

Circumferential Crosshead Crosshead Longitudinal CM 1.1 TIRM2 BIRM4 VM-10 CO 14.4 (load cell) VI-20 CM 16.3 VM-40 These liftoff control tendons are included in the control tendon group for visual inspection.

Therefore, the historical surveillance information summary including measured liftoff loads for each of these tendons is also presented in Table 2.2-1.

Bottom crosshead tendon BIRM4 is equipped with a load cell.

The load cell reading during the most recent liftoff was 1257 kips.

I Comments were made in Section 2.2.1.1 concerning the results of the visual inspection of the wire bundle of these tendons.

-The load-carrying effectiveness of each of the control tendons is not showing any signs of relaxation or degradation from earlier liftoff surveillances.

The slight differences in measured lifoff load values from

Page 17 of 52 one liftoff to the next are due primarily to liftoff jack inaccuracies and to slight human inconsistencies from one liftoff to the next.

For these reasons and also because, I

to date, not enough lif toff data is available for any one

tendon, it has not been possible to attempt to trend tendon load versus time for any tendon based on measured I

liftoff loads.

(See Section 2.3.4 concerning load cell surveillance.)

However, in all cases the tendon loads measured to date I

are well above the minimum allowable tendon loads triggering mandatory engineering evaluation as specified in the most recent draft of the proposed Technical I

Specification for PCRV and Confinement Systems (draft date: November 30, 1985, submitted under Letter P-85448, dated November 27,1985).

2.2.2.2 New Tendons The new tendons for liftoff testing for the first eighteen-month interim surveillance period will be selected at a later date and the findings reported in a future submittal of these semiannual interim surveillance reports.

l 2.3

~

SUPPLEMENTAL SURVEILLANCE INFORMATION 2.3.1 Tendons with Non-effective Wires Table 2.3-1 provides a complete summary of all tendons I

surveilled from March 1, 1984 (the start of increased surveillances) through January 4, 1986, which have been i

observed with non-effective wires.

Non effective wires i

are defined as wires which no longer carry any load.

Also, in the case of each of the tendons VM-17, BILU4, TORL2 and CO 2.5 the number of non-effective wires reported includes one non-failed wire removed for laboratory examination.

Any inadvertant errors in the number of non-effective wires and inadvertent deletions of tendons with non-ef fective wires in the March, 1985 Tendon Surveillance Report have been corrected /added and noted in Table 2.3-1.

The last column of Table 2.3-1 represents the number of new or additional non-effective wires observed since I

February 27, 1985 (the effective cutoff date for the results reported in the March, 1985 Report).

Four tendons, VM-17 (bottom end), BIRU3, BILL 3 and BORM4, were observed with one or two additional non-effective wires compared to the number reported from surveillances made before February 27, 1985.

Inexplicable discrepancies between pre-and post-February 27 surveillances exist in I

E E

.E E

Page 1 of 2 TABLE 2.3-1

SUMMARY

of T[NDONS OBSERVED WITH NON-EFFECTIVE WIRESf1)

Total Number Total Number Number of New of Non-ef fect ive Wi res of Non-effective Weres or Additional Non-effective Tendon Tendon obse rved Ob se rved Wi res Observed Number Endf2) 03/01/84 thru 02/26/85f31. f41 Q2/27/85 thru 01/04/86f41 02/27/85 thru 01/04/86 UM-1 Bottom 1(5) 1 0

UI-2 Top 5

N/S VM-8 Top 4

4 0

VI-10 Top 5

N/S VM-10 Top 7

7 0

VM-11 Top 1

N/S 00-14 Top 4

N/S VM-17 Top 6(6)

N/S UM-17 Bottom 1(7) 3 2

UM-29 Top 1

1 0

VM-30 Top 22 N/S VM-31 Bottom N/S 1

1 UI-35 Top i

N/S VM-37 Top 1

1 0

VM-42 Top 2

N/S BILU3 1-11 16(8) 16 0

BILU3 IV-V 20 20 0

BIRU3 1-11 0

1 1

BILU4 1-11 28 28 0

BILU4 IV-V 3(9) 3 0

BORU4 IV-V 3

3 0

BILL 3 II-1II O

1 1

BOLL 4 V-Vi 1

0 0

BORL4 V-VI 2

1 0

BOLM3 III-IV 1

1 0

BILM3 VI-I 1

1 0

BOLM4 til-IV 3

3 0

BORM4 til-IV 1

3 2

TIRL2 1V-V 1

N/S TORL2 1-18 1(10)

N/S

)

TORL2 IV-V 1(10)

N/S

[

TOLM1 til-V 1

N/S a1 CO 1.1 Not Repo rted 2

O(Both Ends)

O m

CM 2.1 I

N/S 2

2 Cl 15.1 1

1 N/S 00 Cl 15.1 Iil 1

N/S a

CO 12.2 IV N/S 1

4 CO 12.2 VI N/S 1

1 CM 1.3 V

1 N/S

- )

CO 16.2 IV N/S 1

1 CO 5.3 til N/S 1

1 CO 8.3 Ill N/S 3

3

Page 2 of 2 TAftF 2.3-1 icon W

SUMMARY

of TE NDONS OBSIRVED WITH NON-Ef f f CTIVE WIRESf 1)

Total Numt e r Total Number Number of New of Non-ef fective Wi res of Non-ef fective Wi res or Addi tiona l Non-effective Tendon Tendon Observed Ob se rved Wi res Observed Number fodf21 03/01/84 thru 02/26/85f31. f41 Q2/27/85 thru 01/04/86f41

_ 02/27/85 thru 01/04/86 Cl 10.3 Ill N/S 1

1 CO 16.3 til N/S 1

1 CO 16.3 V

N/S 1

1 Cl 5.4 VI N/S 2

2 CM 6.4 ll N/S 1

1 CM 7.4 II N/S 1

1 CO 9.4 VI N/S 1

1 CO 2.5 1

3 N/S CO 2.5 V

16(11)

N/S CM 15.5 I

1 N/S CM 15.5 V

1 N/S Cl 12.6 Il 1(12)

N/S Cl 12.6 IV 1(12)

N/S Cl 14.6 11 2(12)

N/S CM 14.6 IV 1(12)

N/S CO 17.6 Not Reported 1

N/S NOTES:

1) All tendons listed have 169 original wires except Cl 15.1 CO 12.2 CO 5.3, CO 8.3, Cl 10.3, Cl 5.4, CM 6.4, CM 7.4, CO 9.4, CM 15.5, Cl 12.6 and Cl 14.6 which have 152 origina l wi res.

2) Indicated by PCRV buttress number.

If between two buttresses, indicated by both nearest buttress numbers, for vertical tendons indicated by top or bottom.

3) Reported in Ma rch 18, 1985 Tendon Surveillance Report, except as noted.

Q)

"N/S" means that this tendon end was not surveilled during this time period.

5) Not reported Ma rch, 1985; top end observation (no failed wires) was reported.

6) This is a correction; five (5) ra iled wi res were reported March, 1985.

7) Nat reported Ma rch, 1985; top end cbservation only was reported, o",

c

8) Not reported Ma rch, 1985; end IV-V observa tion wa s reported.

8D

9) Not reported Ma rch, 1985; End 1-18 cbservation was reported.

O o

10) This is a correction; no failed wi res were reported Ma rch, 1985.

11) This is a correction; fifteen (15) non-ef fective wi res were reported Ma rch, 1985.

12) Not reported Ma rch, 1985.

the field-reported number of non-effective wires for tendons 80LL4, BORL4 and C0 1.1.

The latter result in Table 2.3-1 is correct for CO 1.1; non-effective wire l

numbers for 80LL4 and 80RL4 will be vertfied by future surveillances.

I Not all of those tendons observed with non-effective wires prior to February 27, 1385, have been resurveilled since that date.

Conversely, not all of the tendons I

observed with non-effective wires after February 27, 1985, were surveilled prior to that date.

Generally speaking, Table 2.3-1 shows that there has been I

no accelerated wire breakage over the past twenty-two months of increased surveillance; it also shows that some minor wire breakage and, thus, minor corrosion has I

occurred in the circumferential tendons in addition to the previously-reported bottom crosshead and longitudinal tendons.

2.3.2 Tendon Surveillance Historical Information The PCRV Tendon Surveillance Plan drawings, showing end I

views of all PCRV tendens, which were first introduced in Appendix A of the March, 1985 Tendon Surveillance Report have been completely updated to reflect the most current information available.

These updated drawings, Numbers I

1A through 10, are provided in Appendix A of this report.

Drawing 1A shows top and reflected-bottom end views of I

all longitudinal tendons.

Drawings 18 and IC show end views of all circumferential tendons.

End views of all top and bottom crosshead tendons are shown in Drawing 10.

I These' drawings provide historical surveillance information for each end of every tendon.

There are a total of 448 PCRV tendons, or 896 tendon ends. Of these 448 tendons, there are 210 circumferential tendons around the " barrel" portion of the PCRV which each consist of 152 original 0.250-inch-diameter wires.

All remaining tendons--100 circumferential " head", 90 longitudinal, 24 I

top crosshead and 24 bottom crosshead--consist of 169 original 0.250-inch-diameter wires each.

The number of original wires in a tendon affects the I

following:

1)

Original tendon prestressing load and,

thus, I

measured liftoff load values:

Each tendon was initially stressed to approximately 7 0*.'

of the guaranteed ultimate tensile strength (GUTS) of the tendon.

GUTS for each tendon is 240 000 psi.

Therefore, for a 169-wire tendon the initial prestressing load was approximately 1400 kips, and for a 152-wire tendon, approximately 1260 kips.

I Page 21 of 52 I

2)

The number of allowable non-effective wires in a

. tendon before triggering a mandatory engineering I

evaluation as required in the current draft proposal o~f the Technical Specification for the PCRV.- (These numbers are 23 or more non-effective wires for the circumferential barrel tendons and 34 or more non-effective wires for all other tendons.)

The information provided on the Appendix A drawings for each tendon end includes the following:

1)

Tendon designation: A heavy oval around the tendon designation indicates that that tendon end has been surveilled since February 27,1985 (the effective cutoff date for the surveillances reported in the Ma rch,

1985 Report).

Therefore, all other tendons I

shown with a light oval around the designation have not been surveilled since February 27.

(A brief description of the tendon designation was included in the March, 1985 Report).

2)

Total number of non-effective wires:

This figure includes failed wires plus any non-failed wires removed for examination (see Section 2.3.1).

3)

Number of new or additional non-effective wires observed since the March, 1985 Report.

4)

Latest surveillance type, either visual inspection

("V") or li f tof f test ("L").

5).

Latest measured liftoff load value in kips:

This

!E value applies to the latest surveillance only in the case where the latest surveillance type (Item (4))

g is "L";

otherwise, it applies to an earlier surveillance.

1 i

6)

Total number of historical surveillances including l

the latest: A visual inspection and a liftoff test l

each count for one surveillance in this total.

7)

Tendon accessibility for surveillance (see " Key" on tendon drawings).

8)

Latest surveillance date:

This date is associated with Item (4).

I It should be pointed out that surveillance information Items (1), (3) and (5) above have been slightly modified or added since the March, 1985 set of tendon surveillance I

drawings. Please note also that all of the information presented within each tendon end symbol on the current drawings is provided on a "per tendon end" basis only; 1.e.,

no assumptions have been made concerning the total I

Page 22 of 52 I

number of non-effective wires on one end relative to the other end.

Those tendon end symbols showing no information signify tendon ends which have never been surveilled since original tendon installation was completed in 1970.

2.3.3 Number and Percentage of Tendons Surveilled To Date I

Table 2.3-2 provides a complete summary of the number and percentage of tendons of each type which have had a given type of surveillance performed on them at least once between March 1, 1984 (the approximate first observation I

date of the current corrosion problems and subsequent increased surveillances) and January 4,

1986 (the effective surveillance cutoff date for this report).

The I

table distinguishes between liftoff test surveillances and visual inspection surveillances.

For the table count, no tendon has been counted twice; for instance, if a tendon has had both a liftoff test a.d a visual l

inspection performed on two separate occasions in the

past, the tendon has been counted only once and appropriately included in the liftoff coun (a liftoff takes precedence over a visual inspection in the table count since a liftoff test includes visual inspection).

All possible combinations of surveillance types for any j

one tendon are shown; therefore, the total sum of i

surveillances shown for each tendon type (each column) equals the total number of tendons of this type in the PCRV.

l l

2.3.4 Load Cell Surveillance PSC made a commitment to the NRC in April, 1984

(

Reference:

PSC Letter P-84110, dated April 12, 1984) to l

monitor the twenty-seven (27) tendon load cells on a l

monthly basis for trends of relaxation or load-carrying effectiveness.

The results of these monthly load cell surveillances as well as any earlier surveillance information available back to 1978 have been presented in I

graphical form (Load Cell Load in kips versus Date) in Figures 2.3-la and b, 2.3-2a and b, 2.3-3a and b and 2.3-4a and b.

Figures 2.3-la, 2.3-2a, 2.3-3a and 2-3-4a present the load cell data randomly available from September, 1978 through March, 1984.

Figures 2.3-1b, 2.3-2b, 2.3-3b and I

2.3-4b present the most current load cell data from the monthly monitoring began in mid-1984.

Please note that straight lines have been plotted between successive data I

points only for the purpose of possible general trending.

It is not relevant or correct to interpolate data between any two actual data points shown for two successive dates by following the straight line.

M M

M Page 1 of 1 LABL F 2. 3-2

$UMMARY OL_HNDONS_Lif_T[D-OF f f 1.1_A3L)&RJJ SUAIMLW2J INSPECifD AT LEAST ONE TIME BETWFfN MARCH 1.

1984 AND JANUARY 4.

1986 l

IENDON TYPE (3) l 1

I l

l BOTIOM l IOP

, CIRCUM {LRfJ1J AL l VERTICAL (4) l CROSSHEAD CROS5 HEAD :

HEAD l BARREL l

I

1. Total Number Of Tendons This Type (5) 1 90 1

24 1

24 1 100 210 l

l l

i I

l i

l ILiftoff, both ends INumber l

N/A 19 13 31 1

85 I

I I

i 1% of Totall N/A 19.2 ll 54.2 31.0 11 40.5 l

i 1

l S,

one end INumber i

8 l

1 9

7 6

lU HLiftoff, i R IVisual only, other end l_

l I

l l V i 1% of Totaa l 8.9 l

4.2 37.5 li 7.0 1

2.9 l l~ E I l

l l

I l

l l 1 ILiftoff, one end INumber l

66 1

0 l

2 1

9 0

L INo visual or lif toff, other end l

l l

l Li 1% or totall 13.3 1

0 1

8.3 1

9.0 0

l I A l l

l l

l N IVisual only, both ends INumber 1

2 1

0 1

0 0

i Ci i

l i

l 1

l E I 1% of Tota a l 2.2 1

0 1

O O

I I

l l

ll l

IVisual only, one end INumber l

N/A 4

i 0

3 I

to I

l T

No visual or li f tof f, other end l

l l

4.8 I

IY 1% of Totall N/A ll 16.7 0

1 3.0 1

l P l

l l

ll l

l l E IVisual only, top end INumber l

13 N/A N/A l N/A l N/A l

lNo visual, bottom end l

l l

1% of Totall 14.4 N/A l

N/A ;l N/A l N/A l

l 1

1 1

1 l

lNo lif tof f or visual, both ends INumber 1

1 1

O l

0 50 1 109 l

l l

l 1

I I

l l

1% of Totall 1.1 1

0 1

50.0 l

$1.9 l l

l_l I

i l

I i

i i

NOTES:

m on C

1) A liftoff includes visual inspection of anchorage assembly and wire bundle; therefore, a li f tof f talse. precedence over a " visual - only" inspection in the tabulation. No tendons a re counted more than once in the tabulation.

N"

2) " Visual - only" means visual inspection of anchorage assembly only; i.e.,

no lif tof f performed to inspect wi re bundle.

o

3) N/A: Not applicable for this tendon typa.

4) Vertical tendons can only and need only be lif ted off on top end.

N

5) Most, but not all, tendons are accessible for lif toff and/or visual inspection.

o Page 24 of 52 N

l f

a t

-92EOb8

?

+

/

l W

/

/, '

I 0

9

\\

-SO60E8 g

\\\\

\\

\\'\\

\\

I I

+

\\\\

\\

l

-SI20E8 1

l I

T r

\\'\\,

\\

l i

g 1

\\\\

\\

l Q

\\\\

\\

l

-922028

\\\\

\\

i a

m

+

, I J

\\.

\\

l o

r c

g P

f R[O

--201028 W J

W I

f l

_J m;

O T

-a I

i y

iw I

v W

l mu l l Q

g I

-619018 gj[ g f

j gf b

T W

f#

T lm o

7c..

s i

e3 o

i[fp

//

/

E a

E

_J

//

f 1

-621108 Q og p5 ll Z

l

/

I i

D

'S I

o O

1, f

i g

4 g

lig C

j I

I I

-iISOO8 J

B Z

u gh 4

o 4

g l

\\

-420162 G

I b

\\

o ho b

4 i

il

/,/

/

5 j

1

-EObO62 l

f/

3 ~

b o' d

s m

o l

l 216082 E

o m

o o

e m

N N

b N

k N

m m

m SdI>i I

I KIPS l

l

~

m w

N w

N A

w N

cn cp N

N N

w w

w l

}

84051v i

O W

)

O 840714-c 9'

f l

l 7

t d

+

9f e

840911--

k dd l

~

O I

4 E

i f

9 H

i Pl

\\

l

\\

z l

o

\\

8

\\

{

j 84110s-7

'I U 9 O

O I

I,1 J

S 1

1 o

z 9]

/

qg a(

g C 850107-

+

rg k\\

\\

OA H

O i i(

i

~D l

g R

am i

(f)850307-i O

t-a m

h J lh

}!

QY l

n f

0 4

n l

F-p

.I r

R 850504-1 i

\\

g r

+

't vt

(~ I j

f

/

a 8

+

4 a

3 850702-g l

\\

O l

~

2 3

t 4

I

+

\\

H I

f k

f 94 D

l 850830-l

~

l

+[

l

+

851028-g a

4 7_i

,9 l

a m

i d

kk o6 8

l E

851226-

+

m 29 JO g2 06Pd

Page 26 of 52 I

l p pgp

-92EOb8

+

/

/ //

l o

4 g //

o i

\\

-SOsOE8

\\\\\\

\\

~

l

\\

\\\\

i

+

1

-S120EB o

l

\\ \\

T

\\

l U

l F-

\\

c T

\\

n l

Q 5

j\\

-022028 v

\\ \\\\

+

7 a

\\ ;) \\\\'

d

\\

i

~

T u

o d

t Po

-ze1028 W J

W

/

J ca l

U F

E NJ t j {ll

-619018 7

j gf l

j Ad U

W Q

}

I f_

W 8

og O

H I

ma I

J

/

./

1 J

y p

-621108 Q cy

/l V

'M z

i I

o

,jl

-419008 m

i a

3 I

g Q

I

f J

l z

i'l l

I e

i49 e

u*

Y l

s \\ '\\x\\

i 5

-t ee t e z o

)I k

8 i

t b l

./ { g ]8

~

\\

8 j,

eavese f

J.

m 9

7 7

l 0

0 5

A R

S E

E m

~

l SdI>l I

o o

_saa158 I

1 e $y

+

g e

,c t

I I

f

-820158 i

[

i i

m I

+

4 do o

-038058 O

l l

D-t "I 9 o

I A

l L

D-

+

r o, o -

-207058 a

c i-l C

l j

s fed 4

s

+

1 l

E i

f $)

-405058nr r

O S

p

\\

\\ \\

l Q

1 ;-< d{8 P

~ ~I

?

m 6

YA

+

-703058)f(

1 a

l C

R no I

I h

6 dk O

7

-701058 C h

!c 3

z

+ +7 1

l

,s o

O

\\

\\(

m a

g g

9 7q

_901148 m

o l

Z I

I 5

o R

I -k}9 D

- 119048

[

j ny y

a u

H r

C E

d Hh ki I

k g

(Yi m

i

-417048

/

i o

7' l l

l1 l

l l

C15048 y

o m

m w

3 m

w w

N m

a m

m a

w O

~

g SPIK I

Page 28 of 52 I

~

D

' /+ -S E E B V B l

,,P

/

P

+

g jl

-SO60E8 9

~

\\

\\\\

t'

-5120E8 o

i T

\\

\\\\

u

\\

T E

s l

Q

\\

Ik

-822028 f

\\

Ik

+

a O

l

\\

~

T J

f)

{

-201028 W U

J ma l

U E

mJ l

$U I

I U

l n

e

./

m l j

ga Q

-s i se l e l

y$

W u

%.N S

H I

O p

//

p ea l

J d

f f

-621108 Q gy E

a i

I Z

il I

K

'M I

o O

I ll l

1 g

C l

l Z

I

- II5008 u

J L

4

-L g

u a

l

\\,

\\- 120162 I

m o

b h[/

I o

8 g

/

$-EObO62 3

b h

m o

l P

216082 I

u e

e m

m e

a b

N Y

v m

I s

Z D

E 9

~

I SdI>i I

dP6a 26 oJ 92 g

l n

0 0

3-

+0 +-E22158

+

~

f

?

l 7

ij Y t -e2et5e

~

l

\\

p\\ -h4 1

l 7

+

a d

l D-9 j -ff -038058 0

l 1

o o

I

{--

l l

l I

h-d+l-

)I-a a

g l

H 207058 P

C d

d4-.d 4 a

+

1 l

F j

i i }i C

S p

\\

\\-405058nr r

l p

J 91~ldJ

?

0F J

m 1+

o 7A 6

g,(

l C

d

-703058 F7 o

h d

F!c -41 g

p 9

f-701058 h

3, Z

?

'c f b

fi O

l i

i o

+} t -901148 n

l

]

o 4

\\

\\\\

\\\\ \\

v z

g lc c

119048 I

4k O

d 6

8 a

y+-

c d

417048 l

9 j

jf

~

f\\

\\g

\\

l3 515048

?

l l

-l o

m w

w u

o l

5 E

0 E

E o

w w

~

g SPIK

Page 30 of 52 w i

.i; l

m

+

o o

+

-92E0b8 j

j fj

/

0 l

4 y

d

+

g

\\.

-GO60E8 l

\\

R

\\

\\;

o E

\\);

-512008 i

+

i j5 E

\\

1 l

l f--

\\,

u E

\\

f ll

{

-622026 C

l Q

\\

(

a

\\

m

\\

l S

U

\\

n l

f

/

- 201028t l

+

ce v

s i

u

,l/

U

'l l u j

C Il 9

C

-619018 4

6 o

ma 1

y

+

0 W

c i

uo O

'+

"w H-s i

J

/

1 l

~

0

+/

p a

-621108 a o

e _;

l I

u i

~C lI Z

I u_ u I:t

~

+

O I

e j

lI l

9 o

C I

,I/

- IIS008 3

z i

W k

2 o

\\

I m

ig w

q i

6 120162 0

j N

-w

\\

r lI

/

/'

/

l

[

-EOb06d ll f

,6 s

i f

~6 7

o 216082 O

i l

0 s

e m

m l

b m

i m

m m

v m

v i

m m

N N

SdIN i

j

.---.-----.-----,...-~.---.---.--,-,-----.,....n1

dP60 [1 OJ 92 m

ll 4

o o d--o

-622158 i

+

~

1 i

i

\\l h

0 dN g

i a

-820158 i

i !~~

ll I

I I

l

\\

w

+

6 d

d+

P o

a g

i

-038058

+

!'E D-

+

9 9

9.~~

T H

I n

i

'5 I

t q

g--

o lg

][

/

g j

-207058 S

b

--0

,l a

7 f +j i

r

+

i 8

~

p

\\ \\

-405058 m 1

j a

r

!g m

3 3

F o

l

F ot la O

/

g/

I n

n l

l m

+

6 66+

il W

wn JC

--703058 i

L T

\\

s 4 h, ~

m

~8 n

i O

1 I

AO l!

H N

o p

y q

qq

-70105 8 a gr h

I f

ff

]

o O

I I

l l

O 3

][

t i

9 ]~

-901148

{

~0 g

Z o

l

\\

l

\\,

i z

y R

o

,l H

i 9

9 9 ~~

o' 9

j o

a d

ot

-119048

+

I f

b b

b F-l j

4 q

q d7

-41704g m

l I

7

![

2 I

l l

l L

o l

j l

3 i

v15048 o

~

a m

w l

P P

P

~

m w

m a

e A

{l w

w m

N SPIK l

Pago 32 of 52 In April, 1984, Tendon VM-17 was detensioned for removal of one wire for examination and then retensioned.

This explains the slight difference in general load cell i

values for this tendon before and after this date.

Referring to Figure 2.3-la, it should be pointed out that for Tendon VI-38 no valid load cell readings were available between April 18, 1981, and March 26, 1984.

Also, no valid readings were available between March 20 and April 18, 1981, for Tendon CI 15.3 on Figure 2.3-3a and for Tendons CO 17.6 and CO 17.5 on Figure 2.3-4a.

The load cell mounted on tendon TIRM1 is suspect. The I

latest lif tof f performed February 21, 1985, on TIRM1 showed a tendon load of about 1350 kips. However, the load cell has been reading consistently around 1050 kips, I

except for one inexplicable spike to about 1200 kips in June, 1985.

Current plans are to replace the load cell on TIRM1 with a newly-calibrated load cell.

Generally speaking, for the total 87-month period covered in the graphs, beginning approximately 8-1/2 years and ending approximately 15-3/4 years following initial I

prestress, some of the load cell tendons have shown a slight tendency towards stress relaxation, as expected, and all load values for all load-cell tendons are well above the minimum allowable tendon loads specified in the I

most recent Technical Specification draft.

All PCRV tendons were intially stressed in early 1970 to I

approximately 70% to 73% (depending on the ambient temperature during prestressing) of the guaranteed ultimate tensile strength (GUTS) of 240 000 psi.

GUTS load for circumfarential barrel tendons (152 wires) is 1791 Kips. GUTS lead for all other tendons (169 wires) is 1991 kips.

I Percentage load relaxation, based on the highest and lowest individual load cell

readings, respectively, available between September 12, 1978, and December 26, I

1985, as a function of initial (1970) tendon load, based 70% GUTS, varies from a low of 4.5 percent relaxation on for Tendon C0 3.2 to a high of 17.0 percent relaxation for Tendon CO 17.6.

I

\\

f 2.3.5 Longitudinal Tendan Bottom-End Anchor Inspection l

l As a result of tendon stressing washer failures reported by Alabama Power Company at its Joseph M. Farley Nuclear Power Plant in the early part of 1985 (

Reference:

NRC IE I

Information Notice No. 85-10, dated February 6, 1985), it decided in May, 1985, to randomly select and inspect was ten longitudinal tendon bottom-end anchor assemblies.

The anchor assemblies were inspected for any signs of

Page 33 of 52 I

failure or potential

failure, or general degradation including evidence of moisture or corrosion.

Five 'of the ten stressing washers were also magnetic particle tested for cracks around the outer portion of the buttonheaded face.

The results of these inspections were reported to the NRC in PSC Letter P-85193, dated June 7, 1985. These results will be summarized here.

The ten longitudinal tendon bottom ends inspected were VM-1 (magnetic particle tested),

VI-3, VI-11, VM-17 (m.p.t.),

VM-18, VM-22 (m.p.t.), VI-27, VM-31 (m.p.t.),

VI-34 (m.p.t.) and VI-38.

The inspections showed no evidence of concavity, cracking, water, general corrosion I

or raised buttonheads.

The magnetic particle tests showed no apparent discontinuities in any of the five washers tested.

It was concluded from these random inspections, and because of the lack of any zinc-coated components in the FSV prestressing system which could possibly cause I

was galvanic cell corrosion, that the FSV prestressing system not exhibiting nor would it likely be susceptible to corrosion and cracking of the type identified in the Farley prestressing system.

Later and on going surveillances of many more tendons have failed to turn up in any stressing washer any

'I visible cracks or extremely severe corrosion which could possibly lead to cracks.

3.0 TENDON CORROSION REMEDIAL MEASURES AND TENDON MONITORING 3.1 REVIEW AND STATUS OF PROPOSED TENDON CORROSION REMEDIAL MEASURES Several possible remedial measures have been proposed to l

arrest the tendon corrosion process which may still be J

I occurring at a slow rate.

Additionally, corrective action may be required to deal with those tendons existing with extensive damage caused by past corrosion.

It has been concluded through previous investigations and analyses that the primary cause of the corrosion in the tendons is by the action of previously living, and I

possibly still living, microorganisms whose original source is not completely known.

These microorganisms

(

were life-supported in the original tendon environment of limited oxygen, warmth, some moisture and the originally I

applied NO-0X-ID CM casing filler, an organic grease with a

neutral pH.

The microbiological action produced organic acids, such as acetic and formic acids, which combined with moisture forming a corrosive solution which

-__u

l Page 34 of 52 l

then attacked accessible uncoated areas of the tendon wir.e.

It is believed probable that many of the I

originally existing microbes and their offspring have been killed through their own action of creating an acid environment. Testing of old grease samples from around the corroded areas has shown the absence of viable bacteria.

It was further confirmed from these investigations that I

grease with the organic acids produced frorr the microbial activity would not cause wire corrosion in the absence of moisture. The testing showed that tha. P v ed farmic acids present in the grease would aps,.

4 tid condense I

along with moisture on the uncoated portions of the test coupons causing rapid corrosion.

I The results of the above-mentioned tests and investigations were reported in the March, 1985 Tendon Surveillance Report.

One important conclusion drawn from the testing and analyses is that acid-caused corrosion as well as any other general corrosion requires the presence and I

chemical interaction of moisture and oxygen.

Additionally, oxygen helps support any acid producing microorganisms which may be viable in the tendon system.

It has therefore been the past intent in the study and investigation of proposed remedial measures that to best stop and prevent corrosion, elimination of the two most I

necessary ingredients for any type of corrosion, moisture and oxygen, should be foremost.

This remains the primary goal of the remedial action being pursued.

3.1.1 Removal and Replacement of Two Existing Tendons for Test i

Purposes I

Prior to implementation on the PCRV prestressing system of a long-term solution to the tendon corrosion problem it has become apparent that it would be highly prudent to test the proposed method (s) on a facility which would simulate the PCRV prestressing system as much as possible on a cost-effective basis.

In this manner the effectiveness and basic problems associated with any proposed method can be investigated and solved in an environment not affected by plant operations.

To facilitate this, it is planned to remove two existing PCRV tendons, install two new tendons in their place, and test the removed tendons outside of the reactor building.

3.1.1.1 Useful Information to be Gained Some of the useful information that would hoped to be gained from a tendon removal and replacement operation I

I Pago 35 of 52 I

for the purpose of testing and analysis are the fol. lowing:

1)

The difficulties and attendant problems involved with the removal of a tendon.

I 2)

The effectiveness of a selected tendon tube cleaning method.

3)

The gas leak tightness of tendon tubes.

4)

The difficulties and problems involved with the installation of new tendons including any negative side effects caused by unidirectional twisting of new tendons (original tendons were twisted in two directions).

5)

From the examinations of the removed tendons:

a)

Remaining original grease coverage.

lgg i

b)

Extent, if any, of corrosion away from the ends of the tendon.

c)

Cause of any corrosion found in (b).

d)

Acid / moisture level of old grease samples e)

Whether tendons can be removed and coiled without disturbing the existing grease on the tendon significantly.

6)

From tendon test facility testing of removed tendons:

a)

Whether tendons can be uncoiled and installed in the test facility without disturbing the existing grease on the tendons significantly.

b)

Effectiveness of flushing away old grease on tendons by the use of a selected synthetic oil, c)

Effectiveness and associated negative side-effects of flushing away old grease on tendon by the possible use of some yet unidentified solvent.

l I

d)

Degree to which a selected synthetic oil will penetrate into and coat the internal wires of the tendon wire bundle after a flush or flush-and-soak period.

e)

Difficulties and problems associated with filling the tendon duct, which houses the

Page 36 of 52 tensioned tendon, by injecting (pumping in) a selected synthetic grease, f)

Resultant corrosive effects of a possible voluntary introduction of moisture or acid / moisture solution into the tendon end cap after grease fill of the tendon tube.

g)

Ease of tendon removal after grease filling the tendon duct.

h)

Determination of best and most cost-effective method for cleaning tendon tubes.

3.1.1.2 Status of Prep rations for the Removal / Replacement Operation of Two PCRV Tendons Advance preparations and arrangements are currently under way to remove two existing PCRV tendons and install in their place two newly-fabricated tendons for the purpose of the testing and analysis necessary to gain insight and find solutions to the problems associated with removal / replacement and implementation of a long-term corrosion prevention method.

The two tendons planned for removal e e TIRM1, a top crosshead tendon, and CO 11.3, a circumferential tendon.

These tendons have been selected for two reasons:

(1)

The tendon ends are at the same or lower elevations than their midpoints.

Their removal will facilitate I

examination of the tendon wires for grease coverage and corrosion at locations away from the tendon ends.

(2)

Bot'h tendons, especially CO 11.3 are easily accessible.

Therefore, problems and difficulties associated with the tendon removal and installation process other than those related to limited accessibility can be dealt with without the added accessibility-related inconveniences.

l Preparations, arrangements and preliminary work which were/are necessary to be made prior to the start of the tendon removal / installation operation include the following:

1)

Resolution of tendon twisting requirements since the I

tendon fabrication contractor has the capability of twisting in one direction only wherea, the original fabrication specification calls for dual-direction twisting.

Wire l_ eng th for tendon fabrication is also a concern.

2)

Modification of vendor's buttonheading equipment to produce buttonheads conforming to the configuration and dimensions required by the FSV buttonhead specification.

I

Page 37 of 52 3)

Development, writing, review, revision and approval of the procedures to be used for tendon removal; tendon installation; quality control; tendon tube cleaning and leak testing; new anchorhead machining, heat treating and mechanical testing; load cell calibration; and tendon wire relaxation testing.

I Each of these procedures is required to meet the original FSV specifications and drawings wherever possible.

4)

Machining, heat treating and mechanical testing of new anchorheads.

E 5)

Stress relaxation testing of wire proposed for new

E tendon fabrication for compliance with specification relaxation criterion.

6)

Preparation and issuance of the Change Notice required to justi fy and perform the removal / installation operation.

The Prescon Corporatior. located in San Antonio, Texas, has been selected to fabricate the new tendons, perform mechanical testing of the new anchorheads, calibrate the replacement load cell and provide supervision for the removal of the two existing tendons and installation of the two replacement tendons.

3.1.2 Use of a Bulk Grease Filler for Long-Term Tendon-Corrosion Protection As stated in Section 3.1, the primary goal of remedial action to stop and prevent tendon corrosion is to eliminate and keep out moisture and oxygen from the prestressing system.

The primary method being pursued at this time to achieve I

this goal is that which should be the most effective:

the use of a bulk grease filler. This grease filler would be injected (pumped) into the concrete-embedded tendon tubes housing the existing unbonded, stressed I

tendons so that all of the void space within the tendon ducts would be filled.

By utilizing this grease primarily as a " void-filler", oxygen and moisture would I

not be allowed to enter the tube and thus to interact with any residual organic acids which could cause further corrosion, or to support any possible remaining live microorganisms which could then produce more harmful I

acids.

The grease to be used for this bulk grease fill should best have the following properties:

1)

A thixotropic, tenacious nature and consistency such that it can be successfully pumped into the tendon-

Page 38 of 52 tube void but yet, after the filling operation is

. completed, will set up into a semi-hardened state at the temperatures involved (approximately 100 F to I

120*F) and possess sufficient tenacity such that it will not run out of the tendon tube or run off of the tendon wires and end anchor assembly.

In order I

to better facilitate the pumping operation the grease should be somewhat liquef f able at slightly elevated temperatures (150 F to 200 F).

Good tenacity is important for two reasons:

(1) so that it will not leave surfaces exposed to any corrosive atmosphere or substances and (2) so that the tendon end cap can be removed for future visual or liftoff surveillances without the grease running out and causing an excessive greasy mess.

I 2)

Non-emulsifiable with water so that any moisture which may enter through a poor seal in 'the tendon end cap will not be allowed to contact any of the grease-covered surfaces of the tendon wires or anchor assembly.

3)

Non-life-supportive of microbacteria which may produce corrosion-causing organic acids.

4)

Little or no conduciveness to chemical change upon exposure to the amount and level of radiation I

expected in the PCRV.

Any Jch chemical change should not cause substantial degradation in grease con si stency, produce significant levels of harmful I

organic acids or generate unsafe levels of hydrogen or other gases.

5)

Good metal corrosion prevention properties when in the presence of a

corrosive organic-acid / moisture / air environment at approximately 120 F.

3.1.2.1 Greases Considered for Bulk Grease Fill 3.1.2.1.1 Visconorust 2090-P4 As was reported in the March, 1985 Tendon Surveillance Report, the feasibility of using Visconorust 2090-P4 petroleum-base grease for use as a grease filler in the FSV tendon system was being studied. At that time this grease seemed like a promising candidate for grease fill for the reasons stated in that report.

However, radiation testing on the grease has since been completed and a conclusion of the results indicate that the grease would not be the best to use.

The radiation testing on the Visconorust 2090-P4 was performed at GA Technologies in San Diego utilizing their MKI TRIGA reactor.

The NO-0X-ID CM casing

Page 39 of 52 filler, currently being used in the tendon system, was also tested as a basis for comparison.

The maximum estimated radiation dose that the tendons in the PCRV will be exposed to for the remainder of the reactor design life was determined to be about 20 million I

rads at a gainma dose rate of 100 rads / hour and a neutron dose rate of 10 rads / hour.

To accelerate testing, grease samples were exposed to much higher dose rates in the test reactor to provide a. total dose of 18 million gamma I

rads and 2 million fast neutron rads to simulate remaining life total maximum exposure.

I

Acetate, formate, chloride and sulfate levels of the grease samples were measured before and after radiation exposure. The results are shown in Table 3.1-1 below:

TABLE 3.1-1 RESULTS OF RADIATION TESTING ON NO-0X-ID CM AND VISCON0 RUST 2090-P4 Concentration Levels [ ppm]

Grease and Condition Acetate Formate Chloride Sulfate l

\\

NO-0X-ID CM 22 7

5 11 1

Before Radiation NO-0X-ID CM 219 44 26 137 After Radiation Visconorust 2090-P4 132 111 9

39 Before Radiation l

Visconorust 2090-P4 1214 564 69 234 After Radiation I

The results indicate that the levels of acetate, formate, chloride and sulfate are significantly higher for Visconorust 2090-P4 both before and after radiation exposure compared to NO-0X-ID CM.

From the large increases observed in these levels for the Visconorust 2090-P4, it was concluded that long-term radiation i

significantly degrades this grease.

l l

The increase in sulfate level would not be expected to have any effect on the integrity of the tendons.

The effect of the increase in chlorides is not fully known; however, high-strength carbon steels are normally not i

subject to stress corrosion cracking from chloride inducement, especially at the relatively low temperatures (100 F to 120 F) to which the tendons are exposed in the PCRV.

I

I Page 40 of 52 However, the increase in acetate and formate levels could have the effect of causing increased corrosion in the I

tendon wire.

The earlier investigations and conclusions have attributed the existing tendon corrosion problems to acetic and formic acids produced from the action of microbacteria.

Therefore, any additional or alternate I

source of these same acids in significant levels would not be desirable.

I Although the actual long-term effects of using Visconorust 2090-P4 cannot be fully known from these short-term tests, it has been concluded that due to the significant increase in acid levels produced from this I

radiation test that it would be best not to use this particular grease as the bulk grease filler for the prevention of long-term corrosion.

3.1.2.1.2 Synthetic Grease The effects of radiation on the Visconorust 2090-P4 I

petroleum-base grease were not totally unexpected, and it is likely that radiation would have a similar effect on all petroleum-based greases.

Therefore, it was concluded that if the grease-fill method was still to be utilized for long-term corrosion l

control on the tendons--being the most effective method for the elimination of moisture and oxygen--that the use of a synthetic grease available from The Corsen Company l

near Dallas, Texas, which may be less susceptible-to I

radiation

damage, should be studied.

It was also believed that this synthetic grease may exhibit. other more desirable properties for use as an acceptable grease l

filler.

Recent and current study has therefore been focussed on two types of Corsen synthetic oil / grease products:

"WRP-119"

oil, developed as a

synthetic wir's rope preservative; and "WRL-100", a newly-developed synthetic heavy oil or grease lube product designed to provide the wire rope industry with a protective agent against highly corrosive situations in either acidic or alkali environments. The WRP-119 and WRL-100 products were designed to be highly compatible with each other and used I

in a synergistic manner.

In the tendon system it would be intended that the WRP-119 oil would be used primarily as a temporary corrosion protection agent and the WRL-100 I

grease as 'a tendon tube bulk filler for long-term protection.

i I

To determine the effects of radiation on WRP-119 and WRL-100, GA was again contracted to perform the same type of radiation test as was performed on the NO-0X-ID CM and Visconorust 2090-P4. This testing was completed and the results reported in July, 1985. The total radiation dose I

Page 41 of 52 was the same as the previous test.

The results are presented in Table 3.1-2 below:

TABLE 3.1-2 RESULTS OF RADIATION TESTING ON CORSEN SYNTHETIC OILS WRP-119 and WRL-100 Concentration Levels [ ppm]

Oil and Condition Acetate Formate Chloride Sulfate l

WRPe119 12 2

5 4

)

Before Radiaton WRP-119 154 87 228 96 After Radiation i

WRL-100 15 3

10 6

l Before Radiation l

WRL-100 83 4

41 22 After Radiation I

Compared to the results for Visconorust 2090-P4, the i

acetate and formate levels before and after irradiation for WRP-119 and especially WRL-100 are significantly lower.

1E Since WRP-119 would be applied only to the surfaces of g

the tendon wires and possibly the tendon tube it would not be used in large quantities relative to the WRL-100, which is to be used as a tendon tube filler.

Therefore, it is believed that the acetate and formate levels generated by radiation in the WRP-119 are not significant.

As #or the WRL-100, the acid levels produced are considered low enough not to present any acid-related corrosion problems.

From I

the radiation testing it was also reported that gas was generated during the course of the test which, as reported, may cause undue pressure increase in the tendon system. However, this is not considered to be a problem I

in that in the PCRV application any gas buildup would be sufficiently slow so as to have time to migrate through the concrete thereby preventing any pressure buildup.

I Additionally, the tendon end caps are currently vented with pressure-relief valves at a safety measure from expected off gassing of the original NO-0X-ID CM grease.

To determine if microbacteria of the type which might be found in the tendons could survive in an environment saturated ~with WRP-119 and WRL-100, Biotest Inc. in I

Page 42 of 52 Petersburg, New York (Dr. Daniel H. Pope, President) was contracted to perform a series of tests.

First, WRP-119 and WRL-100 samples were tested directly to determine if they contained any bacteria.

No bacteria was grown from either sample.

A suspension of large numbers of certain microbacteria was made up and mixed with samples of each oil and incubated at room temperature for a certain number of I

hours.

Samples of old NO-0X-ID CM and combinations of WRP-119, WRL-100 and NO-0X-ID CM were also tested.

The number of bacterial cell colony-forming-units (cfu) per I

milliliter of test mixture, known as the viable count for the mixture, was determined before, during and after the 72-hour incubation period.

The results of the several tests were consistent.

The NO-0X-ID CM failed to kill any test bacteria over a five-day test period. The WRL-100 did not kill the bacteria I

immediately; however, there was evidence that WRL-100, by itself, would kill the bacteria on extended exposure.

The most notable and consistent effect (from test to I

test) was seen with the WRP-119.

By itself, WRP-119 killed all of the original bacteria in less than 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

Even on test wires which were first coated with I

the bacterial suspension, then a layer of NO-0X-ID CM and then a covering of WRP-119, complete elimination of the test bacteria was observed within 24 to 48 hours5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months of WRP-I 119 exposure.

It appeared that the WRP-119 would penetrate the NO-0X-ID CM and " clean" the wires of live microbacteria.

From this testing it was concluded that WRP-119 would be a good candidate for application to the existing tendons to help clean out the old grease and kill any I

microorganisms remaining in the system.

Because WRL-100 killed bacteria over a longer term it can also be considered non-life-supportive of microorganisms and therefore an excellent candidate for use as a grease filler from the standpoint of preventing any future microbial-related corrosion.

I WRP-119 and WRL-100 are not miscible nor emulsifiable with water so that as long as at least some thickness of the oil / grease exists on the surfaces of the tendon parts moisture will not penetrate to the surface, possibly I

causing corrosion.

In addition, both synthetic oils are essentially non-toxic.

I The corrosion protection capabilities of WRP-119 and WRL-100 in the presence of highly-acidic atmospheres were tested by GA. Tendon wire samples were coated with each oil and suspended half-immersed in a solution of 5000 ppm I

Page 43 of 52 I

acetic and formic acid in water. The containers were then sealed and placed in an oven at 100 F for one month.

I The results indicated that the WRP-119 afforded little protection from corrosion in this environment while the WRL-100 provided fairly good protection.

As stated earlier, for new replacement tendons it is intended to use WRP-119 primarily as a

temporary corrosion protection agent during shipment, storage and I

during an interim period following installation until grease-filling has been thoroughly tested and can be implemented to provide long-term corrosion protection.

I For existing tendons it is intended to flush out as much of the old grease and existing acids as possible with WRP-119 or perhaps some yet unidentified degreasing solvent.

I Corrosion protection abilities of the synthetic oils on tendon wire in the presence of an acidic atmosphere I

appear to be a direct function of the ablity of the oil to adhere with sufficient thickness to the surface of the wire. As gravity pulls off the oil from the wire surface leaving a very thin or no layer of oil, the wire becomes I

viscosity oil which is not intended and cannot be more susceptible to corrosion.

WRP-119 is a low expected to keep a sufficient.y thick coating on wire I

under the force of gravity to prevent corrosion in highly corrosive environments.

It is, rather, the intended purpose of the WRL-100 type I

oil /gr-ase to provide the high, long-term corrosion protection for the tendon wire. Additionally, it is the purpose of the WRL-100 type grease to completely fill the I

tendon-tube voids thereby eliminating oxygen and moisture needed for corrosion.

I Based on the tests and analyses performed to date on the WRP-119 and WRL-100 synthetic type oil / grease it is considered that they are excellent candidates for use as corrosion protection agents in the PCRV tendon system.

At least one problem, however, remains to be completely resolved with the WRL-100.

The consistency of the I

current formulation is such that at the expected tendon system temperatures of 100 F to 120 F it is too fluidic in nature to allow it to remain in place under the force of gravity.

It needs to have the ability to set up into I

a more semi-hardened, non-fluidic gel state after it is pumped into the tubes.

PSC is currently working with Corsen to develop a WRL-100 type grease exhibiting a more acceptable consistency at 120 F.

I l

Page 44 of 52 3.1.3 Nitrogen Blanket System for Tendon Corrosion Protection As 'was stated earlier, a bulk grease fill system is the I

primary tendon corrosion method being considered at the present time. Failing the ability to utilize the grease fill system successfully on all of the tendons may I

require going back to the concept of a nitrogen blanket in the tendon tubes.

It was found through earlier investigation that a dry nitrogen atmosphere would be an effective means of control of corrosion resulting from I

the action of acetic and formic acids on tendon wire.

Successful use of a nitrogen blanketing system without I

the necessity of excessive and costly nitrogen make up depends on the ability to provide an acceptable degree of gas sealing inside the tendon-tube /end-cap arrangement.

I Sealing tests performed to date have not proven to be totally successful.

Figure 3.1-1 shows a sketch of the cross-section of a typical tendon end anchor assembly.

Not shown in the sketch is the tendon itself which travels through the tendon tube and is anchored by cold-formed buttonheads at I

the composite washer.

The tendon outside diameter is such that it does not completely fill the tendon tube.

The purpose of providing this sketch is to show an I

identified gas leak path from the inside of the tendon tube to atmosphere.

This leak path is as follows:

from the tendon tube, around the end of the tube (through the I

tube-to-split-shim gap), through the annular gap between the tube outside diameter and bearing plate inside diameter and finally between the bearing plate-to-concrete interface and/or through a

network of I

microcracks or permeable pores in the concrete itself.

The gaps between the tendon tube, split shims and bearing plate were not rigidly sealed (welded) during initial I

construction to allow for differential movement between the tube and bearing plate due to tendon stressing and thermal expansion.

Several nitrogen leak rate and sealing tests have been performed, all on selected bottom crosshead tendons, to both identi fy the leaks and make attempts to seal those I

leaks identified.

A discussion of these tests. and results follows.

3.1.3.1 Tendon Cap Seal Improvement and Initial Leak Rate Testing The 0 ring seal between the tendon end cap and bearing plate appears to-have been originally designed for outside pressure (atmospheric) greater than inside pressure. Although the existing seal was determined to be adequate for inside pressures up to 10 psig, it was I

I

Page 45 of 52

.l

\\l.

S O RN6 SEAL.,16.455*1Q x o.sc THK. NEOPREME; r%RRER SEAL CO. OR EQUAL

~

wm.)

EMD ANCHOR Ass'Y COVgg BEAR \\N6 PLATE]

l

\\

r o-

/

y' xNJ::-l 1 l

I

' SPLIT SHLM

\\'

~

3 r

coMPostTE h

STEEL TUBE WASHER 7Y"OIA, o

4 GRADE 1OtO AgT/

h \\'yN\\w' 4

a l

o

,,, g I

/

~

4 j

5 d

p

,c s

mxmsmv j{

?

ln

?

o g

g a

sxsxxxsxxs e

1 r-

__mw v

xxxxxwx' q

y q

o I

m\\xs\\

s

\\\\s\\

d N\\x\\x\\h VES$5L o

x l

ew =hJr vn,aE g

- J 4 To r

=

l I

I TEMOOM END AMCHOR ASSEMBl.Y - Cross SECTIOM FisuRE 3.t-1 I

I

Page 46 of 52 I

decided to circumvent any possible leakage by modifying the, seal on those' tendons being tested.

This modification consisted of adding an 0-ring retainer I

around the outside of the 0-ring.

After the 0-ring seal modification was made, nitrogen I

leak rate testing was performed on six bottom crosshead tendons.

The six tendons were connected to a common header and the leak rates at 6 psig and 2 psig were measured.

For the six tendons combined, the total I

nitrogen usage rate at 6 psig and 2 psig, respectively, was 7.69 cubic feet per hour (cfh) and 3.03 cfh. When these results are linearly extrapolated to 448 tendons, to maintain 2 psig pressure in all tendon tubes would require a total nitrogen make-up of 9306 cubic feet per day.

This is equivalent to 42 bottles of nitrogen (225 I

cubic feet per bottle) per day, or one high pressure trailer (150 000 cubic feet per trailer) every sixteen days.

Based on these results it was recommended that an attempt should be made to identify the source of the leak (s) and try to make repairs to reduce the leakage.

Further testing was therefore performed with these goals in mind.

3.1.3.2.

Concrete Surface Sealer Nitrogen pressure was collectively applied at 2 psig to the same six bottom crosshead tendons. A baseline leak rate was established. A soap bubble " snoop" solution was I

then used to locate leaks.

This snoop test revealed nitrogen leakage on several tendons at both the bearing-plate-to-concrete interface and from minute cracks in the concrete surface surrounding the bearing plate.

Two leaking tendons were selected for a sealing test.

The concrete surface surrounding the bearing plate was cleaned to remove paint and other grime.

Then a penetrating masonry sealer consisting of sodium silicate and an inert catalyst, supplied by Ecko Chemical Company of Denver, was applied.

After a set-up time, a snoop test was again performed at 2 psig and slight leakage was still observed at the same location on one of the tendons.

The combined leak rate at 2 psig for the six tendons was again measured and found not to have decreased.

Therefore, it was concluded I

that this concrete sealer does not appear to be a viable option to prevent nitrogen blanket leaks.

3.1.3.3 Braided Asbestos Packing The next nitrogen sealing test performed made an attempt to seal the identified leak path closer to the initial source of the leakage. This test utilized Garlock 3/8-I

Page 47 of 52 I

inch-square braided graphite-impregnated asbestos packing to, fill the gap between the tendon-tube end, split shims and bearing plate (refer to Figure 3.1-1).

In order to

, I access the gap for packing installation, a liftoff is required to remove the split shims.

I This packing seal test was performed on one bottom crosshead tendon. A soap bubble snoop test on each end l

showed virtually no change in leakage on one end wMle on

g the other end almost all leakage was eliminated.

Leak 3

rate was reduced by approximately 60 percent following seal installation.

I It is believed from the lack of totally positive results and from the difficulty of installation of the packing rings that their use for sealing gas leaks would not be a wise course of action.

3.1.3.4 Resin-Polymer and Epoxv Concrete Sealing System The latest nitrogen sealing test involves the injection of a methyl-methacrylate resin polymer with a two-component catalyst into snoop-test identified microcracks I

in the concrete surrounding the bearing plate, and a sealing coat of two-component epoxy applied to the surface.

This concrete sealing system was supplied and applied to the PCRV for the test by Restruction I

Corporation of Denver.

In this system the injected polymer is intended to fill I

the cracks to some immeasurable depth to provide the primary. defense against gas leakage originating from the tendon tube and traveling through the concrete microcrack I

network.

The purpose of the epoxy coating is to seal around the resin polymer injection ports during injection and to provide a permanent second line of defense against nitrogen leakage.

Three bottom crosshead tendons (six tendon ends) were selected for testing. As-found leak rates from 10 psig I

to 2 psig were established for each tendon. After this the surrounding concrete was snoop-tested at 10 psig, and the gas leaks from minute cracks identified and marked.

The concrete surface was then cleaned and the injection I

ports set into place over the microcracks and sealed with epoxy. After the resin polymer was injected and allowed to set up, more leak testing was performed at 10 psig to I

determine if the same or new leaks could be identified.

In all cases the originally identified leaks were well-sealed; however, new leaks outside the perimeter of the first sealed area were discovered in each case. After a

'I second injection /spplication still more, but fewer, new leaks were identified out further yet away from the bearing plates. A third application was not made.

Page 48 of 52 Final as-left leak rate results are not in yet but preliminary results at 10 psig indicate that the leak rats was not improved in two tendons and reduced by approximately one-third in the third tendon.

Final leak rate testing will be performed to determine as-left leak rates down to 2 psig.

From the rediscovery of new leaks more distant from the bearing plate after each application, it is believed that the microcrack network in the concrete allowing gas intrusion is more extensive and complex than originally expected.

Another possibility is that gas was seeking and traveling down minute channels formed along concrete I

reinforcement bar created by concrete shrinkage following original placement.

Additionally, it was noted that the polymer / epoxy sealing I

process takes considerable time to implement.

A major portion of the time is spent setting and sealing the many polymer injection ports required on awkwardly-oriented pCRV surfaces.

3.2 TENDON MONITORING 3.2.1,

Additional Tendon Load Cells It would be desirable to install load cells on some of I

the presently unmonitored tendons so as to provide a direct indication of the load-carrying integrity of more than the twenty-seven tendons currently equipped with I

load cells. This refinement would provide an increase in the degree of overall monitoring of PCRV integrity.

Since extra tendon length is required for the currently-I used type of load cell, tendon replacement is a

prerequisite for installation of this type on more tendons. Therefore, a load cell design which could be I

used in lieu of or in series with the present split shims between the bearing plate and stressing washer would be much more cost effective.

Of the two basic types of new load cell designs proposed in the March, 1985 Tendon Surveillance Report, the split shim load cell assembled from twelve (12) individual I

compression load cells was selected for prototype j

development and testing.

GA Technologies has been contracted for the development and early testing of this I

design.

i A sketch of a typical individual compression load cell is provided in Figure 3.2-1.

A full bridge strain gage circuit is used in each load cell.

Page 49 of 52 I

l'.LECTRt< A4 7

[

\\

Sf (q\\

\\

I i

\\

3 To p VtEyJ I

T i

l 10.0 SPHERtCAL RADtuS g

CRALL M%g f: ROM SOTrom l

AND IN%TWbb.

L I

S.co t--

7 GAatLS LA SQLE

-I l

l

(

CPATC4TED PRouid I

l l

CE i

2-1 I !

-1 Toaa oma oecssos

_H AAo tAsTwLL. GAw5 I

ig oAw as weLan) r-e s

2c>--*-

I (I

[cD

'I OV OcTroNN vie.W I

IP_5,oco La Lo Ao mtt.

I INDIVIDIAAL COMRESSION LOAD CELL [TYPICAO g

FIGURE 3.2-1 I

i Page 50 of 52 Compression load cells for prototype assembly testing will be supplied by the Strainsert Company located in Pennsylvania and Metrox Inc. of San Diego.

Each company can supply load cells meeting the desired specifications established by GA.

A design for a prototype split shim lead cell assembly utilizing the individual compression load cells has been developed.

One side of o'ne such split shim assembly I

designs is shown in Figure 3.2-2.

The dimensions of the assembly are such that it can directly replace one half of the existing tendon split shims. The proposed total assembly is composed of twelve of the strail compression, or columnar, load cells evenly spaced in a circle so that six load cells are part of each. half shim. All twelve individual load cells will be wired in parallel to provide one load output per tendon.

After assembly of the two prototypes, they will initially be tested to determine their sensitivity, accuracy, I

nonlinearity, hysteris and repeatability. The effects of a simulated warped bearing plate will also be tested since some of the bearing plates on the PCRV are known to I

be slightly warped.

Temperature sensitivity and calibration methods will also be-tested.

The prototype load cell drawings and testing and calibration procedure are currently under revision and review.

Prototype assembly and the above preliminary testing can begin following approval of the drawings and procedures.

Following completion of the preliminary tests on the I

prototypes, it is likely that they will be further tested for long-term stablity and creep sensitivity on the jack calibration block at Fort St.

Vrain, and finally installed and tested on PCRV tendons to evaluate their performance under actual operating conditions.

After completion with successful results of the above I

testing, more load cell assemblies can be produced, calibrated and installed.

Installation requires a tendon liftoff; therefore, they can only be installed on those tendons accessible for liftoff.

3.2.2 Continued Tendon Surveillance I

Until such time as an effective tendon long-term corrosion control method has been established and successfully implemented, tendon visual and liftoff surveillances will continue and the results reported-on a I

six-month periodic basis as specified in the current interim surveillance program.

I I

Page 51 of 52 I

,g/y g;

I

/

//

x

'e G

N.N i

tTomvinunt I

s y$

commentoa Q

p r

Loan cac v

./

,. x.

\\,.,s r'

J.ll }@\\ '}nJ @l o

. t g/ %

'h %A;3-? e

,,.d

.. x.

n...

.i

./

l 1

, =

e-

=

m

~

I 5

,h 5

s

,/

m k

~

x-

=

-9 e i.

s j.,, s.,

7

[

.,-*I.

4

ii a

l m

!l N

IN b

s.

1 r.

I te

=

ah_

c c

r

.g i

f i

-dl C3Y l

)

SPLI T-5'HIM LOAD CELL ASTEMGL4 hl0TDTWE

\\

l (V2 or %rAL AKFrt1SLV [ dot.t)Al)

Ficopz 3.2 -2 a

s

+

Page 52 of 52 APPENDIX A PCRV TENDDN SURVEILLANCE PLAN DRAWINGS Drawing Number Tendon Type 1A Longitudinal IB Circumferential Layers 2, 5 and 4 IC Circumferential l

Layers 1, 6 and 3 I

10 Top Crosshead i

Bottom Crosshead 1

l E

!I i

}

)

I i

i

t OVERSIZE DOCUMENT

~

PAGE PULLED SEE APERTURE CARDS NUMBER OF PAGES:

ACCESSION NUMBER (5):

3b0123 018 3

\\%4 its l17 l

l 1

~

i APERTURE CARD /MARD COPY AVAILABLE FROM RECORD SERVICES BRANCH,TfDC FT5492-8989 t

l

.

ML20137M086

Contents

Text

1.0 INTRODUCTION

1.0 INTRODUCTION

Reference:

SUMMARY

SUMMARY

SUMMARY

SUMMARY

SUMMARY

SUMMARY

SUMMARY

SUMMARY

SUMMARY

SUMMARY

Reference:

Reference:

Navigation menu

ML20137M086

Text

1.0 INTRODUCTION

1.0 INTRODUCTION

Reference:

SUMMARY

SUMMARY

SUMMARY

SUMMARY

SUMMARY

SUMMARY

SUMMARY

SUMMARY

SUMMARY

SUMMARY

Reference:

Reference:

Navigation menu

Search