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GA-A13351

CONSTRUCTION, TESTING, AND INITIAL OPERATION OF FORT ST. VRAIN PCRV

byF. S . OPLE, JR. , a n d A. J. NEYLAN

APRIL 18, 1 9 7 5DISTRIBUTION OF THIS DOCUMENT UNLIMITED

DISCLAIMER

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency Thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document.

NOTICEThis report was prepared as an account o f work sponsored by the United States Government.

Neither the United States nor the United States Energy Research and Development Administration, nor any of their employees, nor any of their contractors, subcontractors, o r their employees, makes any warranty, express o r implied, o r assumes any legal liability or responsibility for the accuracy, completeness o r usefulness o f any inform ation, apparatus, product o r process disclosed, o r represents that its use would not infringe privately owned rights.

4j

'TME E N E R A L A T O M I d

GA-A13351

CONSTRUCTION, TESTING, AND INITIAL OPERATION OF FORT ST. VRAIN PCRV

by F. S. OPLE, JR. , a n d A. J . NEYLAN

This is a preprint of a paper to be presented at the International Conference on Experience in the

Design, Construction and Operation of Prestressed Concrete Pressure Vessels and Containments for Nuclear Reactors,

September 8 -1 2 , 1 9 7 5 , York, England, and to be printed in the Proceedings.

Work supported by the U.S. Energy Research and Development Administration under Contract AT(04-3)-633.

GENERAL ATOMIC PROJECT 0 9 0 0 APRIL 18, 1 9 7 5

-------------- NOTICE--- -------------This report was prepared as an account o f work sponsored by the United States Government. Neither the United States nor the United States Energy Research and Development Administration, nor any of their employees, nor any of their contractors, subcontractors, or their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness or usefulness o f any information, apparatus, product or process disclosed, or represents that its use would not infringe privately owned rights.

SYNOPSIS

The Fort St. Vrain (FSV) Nuclear Generating Station is the first station in the USA to use a prestressed concrete reactor vessel (PCRV). The FCRV was designed and constructed hy General Atomic. Construction of the PCRV was completed in 1970; the pressure and leak tests were completed in 1971- The structural behavior of the PCRV has been monitored by installed instrumentation since start of construction. This paper describes the highlights of the actual construction, testing, and initial operation of the PCRV, including a comparison of structural behavior, where possible, between observed data and analytical predictions.

DESCRIPTION AND DESIGN BASES

1. The PCRV was designed circa 19^7 by General Atomic. The design was based on criteria, analy­tical methods, and model test programs developed by General Atomic; the design also complied with the contemporary requirements of the American Concrete Institute (ACI) Building Code for reinforced concrete structures and the American Society of Mechanical Engineers’ (ASME) Boiler and Pressure Vessel Code, Section III for nuclear vessels. The design incorporated many novel features such as the use of preplaced aggregate concrete for the bottom head construction; an internal reinforced concrete floor for core support; the first application of 1000 ton pre­stressing tendons; and thermal protection usinga fibrous insulation material. Much of the data on PCRV description, design, analytical tech­niques, and supporting model test programs have been reported separately in the literature and will not be repeated here except by reference.

2. A detailed description of the PCRV, including design criteria, is given in Ref. 1. The PCRV, shown in Figure 1, is hexagonal in exterior cross- se’ction; the external dimensions are ^9 ft across the flat of the hexagon and 106 ft high. The PCRV has an internal cylindrical cavity which is 31 ft in diameter and 75 ft high. The PCRV wall is 9 ft. thick; the top and bottom heads, which contain multiple penetrations, are 15 ft 6 in. thick. The core support floor is a 5 ft thick steel encased reinforced concrete structure located kO ft above the cavity floor.

3. The PCRV is constructed of high strength concrete reinforced by bonded reinforcing steel and prestressed by ungrouted steel tendons. The prestressing system is sub-divided into three groups: longitudinal tendons, circumferential tendons, and crosshead tendons (see Table 1).The internal cavity and penetrations are lined with carbon steel (3/^ in. thick) for leak- tightness. The liner is anchored to the concrete by welded studs on a 7 1 /2 in. square matrix.

The penetrations are provided with two independent (primary and secondary) closures in series (Refs. 2 and 8 ). A fibrous insulation thermal barrier is attached to the gas side of the cavity liner and the core support floor steel casing. Square cooling tubes are welded to the concrete side of the liner to control liner and concrete temperatures. The concrete temperature is held to a nominal maximum of 130°F and a localized maximum of 200°F (Refs. 3 and 9)•

h. The FSV PCRV is designed to meet elastic limits for the internal cavity pressures listed in Table 2 in combination with temperature and seismic loads. The PCRV is also designed to have an ultimate load capacity of at least 2 .5 times the peak working pressure. Elastic and visco­elastic finite element analytical techniques were developed to predict the behavior of the PCRV (Ref. h). The validity of the analytical tech­niques was demonstrated by comparison with both classical solutions and experimental results from extensive long term (>3 year's) testing of a 1/Uth scale PCRV model (Ref. 5). The analytical pre­dictions of PCRV behavior were further confirmed by comparison with actual data obtained during the proof pressure test as summarized in this paper.

5., Specialty development areas, such as concrete mix design, prestress system development, pressure and leak testing, are referenced in the text.

CONSTRUCTION EXPERIENCE

6. General Atomic had overall responsibility for the construction of the PCRV as prime contractor for the P^V plant. Ebasco Services performed the actual construction of the PCRV as a subcontractor to General Atomic. The construction permit for the FSV Nuclear Generating Station was granted by the U.S. Atomic Energy Commission on September l8 , 1968, followed immediately by placement of the first concrete for the reactor building foundation. The PCRV support ring was completed on February 13, 1969* requiring continuous pumping placement of 575 cu yd of concrete.

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Schedule/Mile stones Concrete Placement

7. The construction of the PCRV from placing the purchase order for the cavity and penetration liners to completion of the pressure test was scheduled for I45 months. Site construction was scheduled to take 33 months. The PCRV was on the critical path for construction of the plant until completion of the prestressing operation. In order to minimize time on the critical path, the bottom head assembly consisting of the steel liner, penetrations, and the core support floor columns, was erected at an assembly area near the reactor building while the foundation and the PCRV support ring were being constructed. In late February 1969, the bottom head assembly, weighing about 1400 tons (including a temporary erection jib, bottom head steel forms, and some reinforcing steel), was moved and positioned on top of the PCRV support ring (Fig. 2).

8. Construction of the PCRV proceeded with concrete placement and prestressing operation in accordance with the following milestone dates;

a. Concrete PlacementJune 19-21, 1969 Bottom head PAC

groutedJuly 17-Nov. 7, 1969 Sidewall concrete

lifts 1 to 13 placedOctober 28, I969 Core support floor

PAC groutedJanuary 7, 1970 Last sidewall concrete

lift ll placedJan. 27-Feb. 13, 1970 Top head concrete

lifts 15 to 17 placed (concreting complete)

b. Prestressing OperationJan. 20-Feb. 6, 1970 Bottom head circum­

ferential tendons tensioned

March 12-18, 1970

March 20-30, 1970

Vertical tendons tensionedTop head circumferen­tial tendons tensioned

March 31-April I8 , 1970 Sidewall circumferen­tial tendons tensioned

April 20-21, 1970

April 22-2 3, 1970

Bottom crosshead tendons tensionedTop crosshead tendons tensioned (prestres­sing complete)

With the completion of the prestressing operation on April 23, 1970, PCRV site construction was completed 13 weeks ahead of schedule.

9 . , As a prerequisite to the PCRV pressure test,the PCRV warm-up was initiated on April 9, 1971,. and on June 30, 1971, the desired temperature condition (120 ^ 5°F liner temperature) was achieved. The initial proof pressure test and leak test of the PCRV were performed during the period of July 29 to August 1 4, 1971 (Refs. 6 and 7) •

10. The PCRV was constructed employing two con­creting techniques. The PCRV bottom head and the core support floor were constructed using the pre­placed aggregate concrete (PAC) technique; the PCRV sidewall and top head were constructed using conventional jobnnixed concreting methods. The successful application of the PAC technique during PCRV construction is described in Reference 10.

11. The mix contained 7-3/14 sacks (728 lb) of Type II (low heat) cement per cu yd of concrete with a water-cement ratio of O.I46. Crushed ande- site aggregates (1-1 /2 in. and 3/^4 in. maximum sizes) were used in the concrete mix. Concrete ingredients were batched in an automatic batching plant at the site and mixed in 8 cu yd truck mixers. Concrete was placed in seventeen 5 ft modular lifts in the PCRV sidewall and top head. An average of one lift was placed per week, employing approxi­mately 300 cu yd of concrete. The maximum concrete temperature was limited to 130°F during the hydra­tion phase. Temperature rise resulting from heat of hydration was controlled by: (l) using low heatType II cement in the mix, (2) mixing and placing concrete at about l45°F, (3) limiting concrete lifts to about 5 ft depths, and (I4) maintaining the ambient temperature near the exposed concrete sur­faces to about 60°F. Figure 3 shows the completion of the last concrete lift at the PCRV top head.

12. The specified design compressive strength of concrete was 6OOO psi at age 60 days; the concrete mix was therefore developed to yield an average compressive strength of 7200 psi, assuming a 10 coefficient of variation corresponding to excellent field quality control per ACI standards. Actual field tests on sealed 6 x 12 in. concrete specimens yielded an average compressive strength of 8870 psi at age 60 days with a 5 .2^ coefficient of variation. The higher than expected field strengths were attributed to the low temperature (l45°F) of the concrete mixes used during construction which allowed reduction in actual mix water content by about 10% for the same workability achieved in trial mix design work conducted at room temperature (73°F).

Prestressing Operation

1 3. Prestressing of the PCRV was accomplished using an ungrouted BBRV-type tendon post-tensioning system. The largest tendons consisted of 169 0 .25 in. diameter "thermalized" wires, having a maximum capacity of 1000 tons. The wires were anchored by means of cold deformed buttonheads to a washer assembly which then transferred the loads onto split shims and a steel bearing plate into the concrete. The low-relaxation "thermalized" wires were produced by Richard Johnson & Nephew, Ltd., Manchester, England. The PCRV was prestressed with a total of W 8 tendons (Table l) . The develop­ment, fabrication, installation, and stressing of the prestressing'tendons were performed by Western Concrete Structures, Gardena, California. Details of tendon prototype-testing, fabrication, instal­lation, and corrosion protection are described in Reference 11.

1I4. Partially shop-fabricated tendons were in­stalled into tendon tubes previously embedded in concrete. All tendon tube sections were spliced

by welding to prevent leakage of grout and to main­tain alignment. Prior to tendon insertion, each tube was checked for clearance to assure passage of the tendon. The tendon was pulled into the tube by means of a pull line attached to a winch. After insertion, all wires at the leading end of the tendon were threaded into the washer assembly and buttonheaded. In order to reduce construction time, tendon installation was started prior to completion of PCRV concreting. This tendon installation pro­cedure required that the corrosion protection must provide adequate protection against corrosion attack from possible contamination during concrete place­ment .

1 5. Stressing was accomplished with 1000-ton capacity jacks from both ends of curved (circum­ferential and crosshead) tendons and from the top end only of the vertical tendons (Fig. U). Prior to the start of the prestressing operation, all stressing units were calibrated for the various operating positions (jacks being vertical, hori­zontal, and inclined). The stressing units were calibrated within an accuracy of _+ 2,^%. Load- extension curves were recorded for each tendon during the stressing operation. Prior to anchor at 70^ of tendon ultimate load, the required thick­ness of the split-shim pack as determined from the load-extension curve was placed between the bearing plate and the washer assembly, after which the force on the tendon was slowly transferred from the jacks to the shims. While the majority of the tendons were stressed in early 1970, some circum­ferential tendons in the bottom head were installed and stressed in mid-1969 in order that the PCRV bottom head could structurally support the weight of subsequent concrete lifts. This early stressing experience prior to the major prestressing operation proved very valuable in qualifying the stressing techniques ahead of time.

PCRV Warm-Up

16. Prior to the pressure test, the PCRV was brought to its operational temperature condition by circulating heated water through the liner cooling system. The warm-up was achieved by incrementally raising- the water temperature at a controlled rate up to a steady-state condition where the average temperature at the liner was maintained at 120 ^ 5®F. Figure 5 shows the progression of liner temperature rise with time. The water temperature was initially raise.d at a rate of about 7* F per week. When the liner temperature reached about 85°F, a two-month hold period was necessitated due to other construc­tion activities, at which time the liner temperature increased to 93°F due mainly to a general rise in the ambient air temperature. Controlled warm-upwas resumed at a rate of lU®F per week after an evaluation of data obtained up to 93®F, together with additional transient thermal analyses, showed the acceptability of the faster warm-up rate. The desired liner temperature of 120 5®F was achieved 80 days after start of PCRV warm-up; the following period of about one month, during which the liner temperature was maintained at 120 5°F, was morethan sufficient to allow the PCRV to reach thermal equilibrium prior to the start of the pressure test,

17. The change in temperature profile through the PCRV wall during warm-up as measured by thermo­couples installed in the PCRV is shown in Figure 6 . The temperature differential between the cavity

liner and the outer concrete surface did not exceed the 50°F limit during the warm-up period. The temperature profile did not change signifi­cantly between July 7 and August 6 , the latter date signifying the time when the PCRV was at the maximum proof test pressure level.

Pressure/Leak Test

1 8. The PCRV was successfully subjected to the maximum initial proof test pressure (IPTP) of 970 psig which is 1.15 times reference pressure (RP) of 8H5 psig (Ref. 6 ). The leak test of the PCRV was conducted at the conclusion of the pressure test. The PCRV leak test is reported in detail in Reference 7*

1 9. A simplified schematic diagram of the pres- surization system is shown in Figure 7* Foreconomic reasons, nitrogen was chosen as the pres­surizing medium instead of helium. Liquid nitrogen was transported to the site in suitably equipped tank trucks for transfer to a pumping unit with a cryogenic pump and vaporizing coils capable of delivering 150,000 scfh of gaseous nitrogen at temperatures up to 120°F. The rate of pressuriza- tion varied from a maximum of 60 psi per hour during the early stages of pressurization to ^bout 15 psi per hour as the higher test pressures were approached.

20. The picssure test vras conducted according tothe test sequence shown in Figure 8 . Nitrogen wasinitially pumped into the PCRV main cavity and penetration interspaces on July 29. After checkout of the pressurization system, the main cavity and penetration interspaces were simultaneously pres­surized to RP of 8U5 psig. The pressure test of the refueling penetrations in the PCRV top head to 1060 psig was then performed. After the refueling penetrations were tested, the main cavity and all the penetration interspaces were simultaneously depressurized to 688 psig. This pressure level was maintained while the 12 steam generator penetrations in the PCRV bottom head were pressure tested to 1060 psig. Pressurization- of the main cavity and penetration interspaces was resumed from 688 psig, and on August 6 , the IPTP level of 970 psig was attained. The pressure in the main cavity and penetration interspaces was maintained at 970 psig for one hour. Up to this point in the pressure test, only the secondary closures of the penetra­tions had been subjected to the test pressure.The main cavity was then isolated at 970 psig while the penetration interspaces were depressurized to atmospheric pressure in order to subject the primary closures to the test pressure. It was observed that the depressurization was proportional to the logarithm of time; about 7 hours was required to reduce the penetration interspace pressure from 970 psig to approximately atmospheric. The pressure test of the PCRV was essentially complete at this point. The leak test was performed with the PCRV at 688 psig. The PCRV was depressurized to atmospheric after completion of the leak test.

PCRV STRUCTURAL BEHAVIOR

21. The structural behavior of the PCRV has been monitored from start of construction. Approximate­ly 550 sensors were installed to measure strain, temperature, tendon load, and concrete moisture

(Table 3). At time of pressure test, approximately 79^ of the sensors remained functional, varying from 55^ for veldable strain gages to 100^ for load cells. At this writing, 5 years after com­pletion of PCRV construction, about 70^ of the sensors are providing valid data. Representative data obtained from the installed sensors are discussed in the following paragraphs.

Construction (Prestress) Data

22, Measured concrete strains from gages located at PCRV wall midheight resulting from application of prestress are shown in Figures 9 and 10.These strain gages were selected in order to show the difference in response between gages oriented axially (Fig. 9) and circumferentially (Fig. 10) in the PCRV as the various stages of prestressing operation progressed with time. The axial gage (Fig. 9) showed significant compression upon application of the vertical prestressing (-120 pin./in.), further compression due to creep while the top head circumferential tendons were tensioned (-20 pin./in.), and some reduction in compression (+60 pin./in.) due to bending effects as the wall circumferential tendons were tensioned. Slight response was indicated by the sixial gage at mid­height as the crosshead tendons were applied. The circumferential gage (Fig. 10) showed essentially no response during the tensioning of both the vertical tendons and the circumferential tendons in the top head. A compressive strain of about -550 pin./in. was recorded during the tensioning of the wall circumferential tendons. Similarly, slight response was indicated by the circumferential gage at midheight during the tensioning of the crosshead tendons. The observed response at PCRV midheight during prestressing compared well with analytical results. Similar assessments made for other areas of the structure showed that internal strain measurements exhibited the expected behavior of the PCRV during application of prestress.

Pressure Test Data

23. Figures 11 and 12 show typical tendon load data obtained during the pressure test. Tendon load changes between atmospheric and IPTP of 970 psig’ as measured by the 17 load cells installed on the circumferential tendons are plotted with respect to PCRV height in Figure 11. The tendon load change profile approximated the expected deformed shape of the PCRV. Typical pressure versus tendon load change curves are shown in Figure 12. Tendon loads varied linearly with pressure changes up to 970 psig. The maximum load change recorded was 26.3 kips in a circumferential tendon at wall midheight, an increase of only 2.3^ over the unpressurized effective prestress force of IIU8 .5 kips. The total tendon load of 117^.8 kips at 970 psig was less than the initial pre­stress force of 1272.7 kips; therefore, the PCRV tendons should not experience a load in excess of the initial prestress force due to pressure loading over the PCRV design life. Figure 12 also shows the pressure versus load curve for a vertical tendon. Of the 6 vertical tendons with load cells, a maximum tendon load change of 7*9 kips was measured at 970 psig, corresponding to a 0.6^ change in the unpres­surized effective prestress force of 1319*7 kips.

2h. Pressure versus strain curves shown in Figures 13 and l4 typify the strain behavior of the PCRV

during the pressure test. The following general observations are pertinent to these strain curves: (1 ) the PCRV response to pressure changes up to 970 psig was essentially linear, (2) the PCRV was stable during the 8-hour hold period at 970 psig, and (3 ) the structural behavior of the PCRV up to 970 psig was predictable as indicated by the good correlation between measured and calculated strains. Figures 13 and li show strain data at the PCRV wall midheight. Maximum circumferential concrete tensile strains recorded at 970 psig were approximately 500 yin./in. at the inner wall midheight of the PCRV as shown in Figure 13. A typical circumferential concrete strain curve at the outer wall midheight is given in Figure 1^; the tensile strain at 970 psig was about 300 yin./in. in this region. Strain measurements indicated no concrete cracking at the exterior wall surface at midheight.

2 5. general, concrete cracks recorded duringinspections performed prior to, during, and at the completion of the pressure test were limited to the exterior surface of the PCRV concrete. The maximum crack width recorded was approximately0.015 inch. Most of the concrete cracks were 0.005 inch wide, varying in length from 6 inches to U feet, and generally following the pattern of the reinforcing steel near the surface of the concrete. Cracks mapped were mostly due to surface shrinkage and temperature effects.

Post-Conslruction Behavior

2 6. Approximately 2 years after the pressure test was completed, the PCRV was subjected to a series of pressure and temperature loadings in June- August, 1973 during the performance of the FSV plant hot functional tests. Sensor data were obtained during the pressure rise from atmospheric to about 623 psig. Representative strain data obtained during the hot functional tests are com­pared with data obtained during the pressure test and calculated strains in Figures 13 and 1 . Good correlation is indicated by the recorded data; essentially elastic response of the PCRV to pressure loading was confirmed. Concrete temperature measurements obtained during the hot functional tests showed minimal change in the temperature gradient across the PCRV concrete sections.

2 7. Prestress force measurements are being con­tinuously recorded from tendons with load cells. Typical prestress load variation with time curves are shown in Figure 15* Tendon load data obtained over the 5-year period from completion of initial prestressing compare well with the expected pre­stress force calculated by a finite element visco­elastic (creep) analysis of the PCRV. Figure 15 also shows the design prestress values which are based on assumed total design prestress losses of 20^ for the vertical tendons and 25^ for the circum­ferential tendons in the PCRV wall after 30 yearsof design life. Assuming that the observed trend will continue over the next 25 years, the prestress losses at the end of 30 years will be close to the expected values which are less than 50% of the allowed total design prestress losses.

2 8. As part of the inservice inspection provisions for the FSV PCRV, selected load cells have been checked for calibration and stability at 1, 3, and 5 year intervals after initial prestressing. Calibration checks obtained thus far show stable performance of the load cells which have

demonstrated an accuracy of ^ 1.0^. Prestressing wire samples provided with selected tendons have been inspected for indications of corrosion at the same inspection intervals as the load cell calibration checks. Reference 11 discusses in detail the results of the corrosion inspections and concludes that the corrosion protection system has satisfactorily performed its intended function.

CONCLUSION

29. In retrospect, the considerable effort expen­ded by General Atomic in selecting and developing a novel reactor vessel concept, and demonstrating the adequacy of such a concept to the US regulatory authorities has proven well worthwhile. The design and construction of the Fort St. Vrain PCRV were completed significantly ahead of schedule. Major problems were identified and resolved during the early stages of component design and development. PCRV structural behavior during the proof pressure test and hot functional tests has corresponded well with analytical predictions. Subsequent structural monitoring has shown continued stable PCRV behavior to date.

7 . Neylan, A. J. and Deardorff, A. F., "Leak- tightness in HTGRs - Experience at Fort St. Vrain," in International Conference: Experience in theDesign, Construction, and Operation of Prestressed Concrete Pressure Vessels and Containments for Nuclear Reactors, 8-12 September, 197^. York, England, The Institution of Mechanical Engineers,1975.8. Cliff, J. 0. and Wunderlich, R. G,, "Construc­tion Experience on PCRV Liners at Fort St. Vrain," ibid.9 . Jones, H. and Hedgecock, P. D., "Thermal Protection System for the Concrete Core Support Floor at Fort St. Vrain," ibid.10. Ople, F. S. (Jr), "Preplaced Aggregate Concrete Application on Fort St. Vrain PCRV Construction," ibid.11. Hildebrand, J. F., "Evaluation of Corrosion- Inhibiting Compounds for the Protection of Prestressing Systems," ibid.12. Neylan, A. J., "The Multi-cavity PCRV,"Nuclear Engineering International, August 197^.

30. The successful construction and initial operating experience obtained with the Fort St. Vrain PCRV has paved the way for future prestressed concrete vessels in the USA. Although the next large High Temperature Gas-Cooled Reactor (HTGR) generating station will employ multi-cavity PCRVs, the basic technology derives largely from the FSV PCRV. Eight PCRVs, accommodating generating capacities of 770 MW(e) and II60 MW(e) compared to the 330 MW(e) HTGR Fort St. Vrain station, are under contract. A comparison of the overall geometry of the FSV PCRV and a typical multi-cavity PCRV is shown in Figure I6 . A detailed descrip­tion of the design of the first ordered multi­cavity PCRV is given in Reference 12.

REFERENCES

1. Northup, T. E. and Peinado, C., "Prestressed Concrete Reactor Pressure Vessel," Nuclear Engineering International, December 19^9.2. Peinado, C. 0., "PCRV Cavity Liners and Penetration Liners and Closures," General Atomic Report GA-8511, February 1968,3 . ' Brislin, R. J. and Jones, G., "Development Program for the Fort St. Vrain Thermal Barrier,"General Atomic Report GA-A13019, July 197^*k. Rashid, Y. R. and Rockenhauser, W., "Pressure Vessel Analysis By Finite Element Techniques," in Conference on Prestressed Concrete Pressure Vessels at Church House, Westminster, S.W.l, 13-17 March 1967> The Institute of Civil Engineers, London,1968.5 . Rashid, Y. R., Ople, F. S., and Chang, T. Y., "Comparison of Experimental Results with Response Analysis for a Model of a Pressure Vessel," Proceedings of the International Conference on Model Techniques. British Nuclear Society, London, July 10-12, 1969.6. Ople, F. S. (jr) and Gotschall, H. L., "Fort St. Vrain Unit 1 PCRV Pressure Test Report for the Public Service Company of Colorado," General Atomic Report Gulf-GA-A10639, December 19T1.

Table 1 - PCRV PRESTRESSING SYSTEM Table 3 - PCRV STRUCTURAL INSTRUMENTATION

Type of Tendon No. of Wires

Max Anchor Force(^) (kips)

No. of Tendons

Longitudinal 169 1395 90, (Head 1I69 (1395 <100• Wall '152 U 255 •210

Crosshead (bottom) 169 1395 2hCrosshead (top) 169 1395 2k

(a) TO^ of tendon guaranteed ultimate tensile strength

Table 2 - PCRV INTERNAL CAVITY PRESSURES

Pressure Level

Normal Working Pressure (NWP) 688 psigPeak Working Pressure (PWP)

Includes transients and control margins

TOk psig

Reference Pressure (RP)Exceeds any operating or accident pressures

8I5 psig (1.2 X PWP)

\

Initial Proof Test Pressure (IPTP) 970 psig (l.lt X PWP)

Sensor/Measurement Total No. of SensorsInstalled Functional*

Load Cell on Tendons 27 27

Vibrating Wire Strain (VWG) Gage in Concrete

110 80

Carlson Strain Gage in Concrete

25 20

Weldable Strain Gage on Rebar

25 13

Weldable Strain Gage on Liner

103 57

Thermocouple (vith VWG) in Concrete 69 60

Thermocouple on Liner 166 155

Moisture Monitor in Concrete

25 21

TOTAL 550 1*33

*At time of PCRV pressure test.

TYPICAL REFUELING PENETRATION

^ \ .ACCESS PENETRATION

^ TENDON ANCHORHELIUM PURIFKATtON WELL

COOLING TU0E8 (TYPICAL)

ICAVITY LINER

TYPICAL CROSS HEAD TENDON ANCHOR

.REACTOR CORE SUPPORT FLOOR

C'*TYPICAL CIRCUMFERENTIAL TENDON ANCHOR------------------ O'

TYPICAL CIRCUMFERENTIAL TENDON

TYPICAL CORE SUPPORT COLUMN;

TYPICAL STEAM GENERATOR PENETRATION

TYPICAL HELIUM CIRCULATOR PENETRATION

COOLING TUBES FEED FOR REACTOR CORE SUPPORT FLOOR

ACCESS PENETRATION

FOUNDATION SUPPORT

LC68930

Fig FSV PCRV general arrangement

HT70553

Fig. 2. Bottom head liner assembly during move in

HT79180

Fig. 3. PCRV top head concrete completion

SE1844

Fig. 4. Post-tensioning of PCRV tendons

125

120

115

110

C 105

§ 100

£ 95Q.S" 90

85

80

75

70

O LINER TO I□ CONCRETE SURFACE TC / .

' WARM-UP START DATE 4/9/71

A 7°F/WK

L/ O

- o o o /

14“F/WK WA

/

o o I

“ O d d□ □

_1__________ I__________ I__________L

O O o

7/29/71 \

□ □ . 6/30/71

J __________ L

O O

□ g

8/14/71

/PRESSURE/LEAKTEST

_l_20 40 80 80 100 120 140 160

TIME (DAYS)

75LC854

Fig. 5. PCRV liner and concrete surface temperatures

125

120

8 /6 /7 1 - PCRV AT IPTP110

CAVITY LINER -

7 /7 /7 1 CONCRETESURFACE105

6 /3 0 /7 1100U Jee3J—< 6 /1 6 /7 1 6 /2 3 /7 1U Ja.SU JJ— 5 /2 6 /7 1

4 /2 1 /7 1

4 /9 /7 1

2 4 0 2 6 0 3 0 0220 2 8 0180 200RADIUS FROM ( OF PCRV (INCH)

Fig. 6. Temperature distribution through PCRV wall

75LC851

SAFETY RELIEF VALVE TANKPCRV

SILENCERi

PRESSURERELIEFVALVEVENT VALVE

SOURCE1 IPRESSURE CONTROL

L____

VALVE AT SOURCE75LC852

Fig. 7. Schematic of pressurization system

10

REFUELING PENET. PRESSURE TEST

END PRESSURE TESTEND LEAK TEST

1100 IPTP = 9 7 0 P S IG -

1 06 0 PSIG1000

RP = 8 4 5 -P S IG

STM. GEN. PENET. PRESSURE TEST ^9 0 0 PCRV

LEAK TEST8 0 0

7 0 0

ALL8 0 0 NWP = 8 8 8 PSIGU Jae= 5 0 0(/></)U Joe 4 0 0a.

3 0 0PRETESTCHECKOUT

NOTE; EQUAL PRESSURE IN CAVITY AND200100

15 16 17 18 19 2 0 211 2 4 5 8 12

| l . 0 j 2 . 8 | l . 9 | - 0 . 4 - | 0 . 3 |

EVENT NO.

- 1 . 5 -------- -ji.oH0 .0 4

•2 0 .50 .2 8

0 .0 4b . 5 | l . 2 | — 4

TIME (DAYS)

Fig. 8. PCRV pressure test sequence

5 .5 8H 4 .o |

75LC849

V E R T . T E ND O NS T E N S ( O N E O T E N S I ON

C O M P R E S S I O N

T OP H E A D C I RCUMF T E N D O N S TENS I O N E D C R O S S H E A D

T E N D O N ST E N S I O N E D

C O M P L E T E POST T E N S I O N I N G O P E R A T I O N

B O T . H E A D C I R C U M F . T E ND O NS

_ T E N S l O N E D 2 0 D A Y S B E F OR E

W A L LC I R C U M F .T E N D O N ST E N S I O N E D

- 100

-20020 30 40

T I M E ( D A Y S )

• 100

- -200

- 3 0 0

-i+OO -

-500

- 6 0 0

T E N S I O N

- C O M P R E S S I O N

C R O S S H E A DT E N D O N ST E N S I O N E D

V E R T . T E ND O NS T E N S I O N E D C O M P L E T E

P O S T -T E N S I O N I N G O P E R A T I O N

T OP H E A DC I R C U M F

B O T . H E A D C I R C U M F T EN D O NS T E N S l O N E D 2 0 D A Y S B E F O R E

T EN D ON ST E N S l O N E D WA L L

C I R C U M FT E ND O NST E N S I O N E D

T I M E ( D A Y S )

75LC589 75LC590

Fig. 9. Prestress strain - axial gage Fig. 10. Prestress strain - circuniferential gage

11

y T J

CO • 19 .6 0 1Cl - 18 .5 o I

CO - 17.3CO - 1 7 .4

\CO - 17 .5

CO - 17 .6 C b s .

Cl - 15.3 O

MEASURED \

CO - 11.2Cl - 10.1 )

CO - 8 .3 O /

Cl - 7 .4 o /

AN A LY S IS . /

CO - 3.1CO - 3 .2

CO - 2.1 /

CO - 2 .2 P

Cl - 1.4 l oCO - 1.6 .. o P 1 I

TENDONS WITH LOAD CELLS

10 2 0 3 0

LOAD CHANGE (KIPS)

75LC848

Fig. 11. Circumferential tendon load change profile at IPTP

1000 IPTP 9 70 PSIG

9 00 -

RP 8 4 5 PSIG

8 00

VERTICAL TENDON □ VI - 247 00

RES1 319.7 KIPS CIRCUMFERENTIAL

TENDON Cl • 10.1600 O Au</)Q . RES

1 148.5 KIPSUJK3 500 O A

UJtr.a.

4 00ANALYSIS

3 00

8 45 PSIG

9 7 0 PSIG2 00 -O 6880 PSIG970

• TENDON FORCE AT START OF PRESSURE TEST

100 <D

0 10 20 30

LOAD CHANGE (KIPS)

75LC853

Fig. 12. Typical tendon load change versus pressure

12

1000

□ INITIAL PROOF PRESSURE TEST

9 0 0

O HOT FUNCTIONAL TEST

ANALYSIS8 0 0

7 0 0

OO= 6 0 0v>a. / % oU fK 5 0 0tnvtLU

4 0 0

3 0 0

200

100

4 0 0STRAIN (/X IN/IN)

5003 0 0 8 0 0 7 0 0200100

75LC856

Fig. 13. Concrete strain at PCRV inner wall versus pressure

1000

900 □ INITIAL PROOF PRESSURE TEST

O HOT FUNCTIONAL TEST

ANALYSIS

800

700

ocP800

500

400

300

200

100

035030050 200 250100 ISO0

STRAIN (m IN/IN)

Fig. 1A. Concrete strain at PCRV outer wall versus pressure

75LC855

13

1500PRESSURE TEST

VERTICAL PRESTRESS1400

c/>£b 1300X

o1200 9oo O

U iCJ1100 CIRCUMFERENTIAL PRESTRESS

AT MIO-WALL</>COU Jact—t/)

1000U IetCL

DESIGN PRESTRESS

EXPECTED PRESTRESS (ANALYSIS)

O MEASURED PRESTRESS900

10 10»ELAPSED TIME ARER INITIAL PRESTRESSING (DAYS)

Fig. 15. Prestress force versus time

30 YR

75LC850

■‘*9 FT. '

3 . 5 FT .

106 FT.

9 1 . 2 FT.

15 FT_L33 FT .

1EL

I1 0 0 . 5 F T . -

8 FT .

D’l D

FSV 1160 MWTYPE IN T E G R A T E D , S IN G L E C A V IT Y IN T E G R A T E D , M U L T IP L E C A V IT Y

O P E R A T IN G 7 0 0 P S IG SAMEPRESSURE

GAS TEMP 1 4 5 0 ° F I 4 I 3 ° F

TENDONS L IN E A R ( 1 0 0 0 T O N ) L IN E A R S AM E, ALSO W IRE

C O O LIN G C E R A M IC F IB E R IN S U L A T IO N ,WRAPPED

SYS TE M WATER C O O LIN G C O IL S SAMECONCRETE 1 5 0 ° F SAMETEMP (M A T )

O THER CONCRETE T E M P ., S T R E S S E S , E T C . SAME

— 12 F T .

LC92347

Fig. 16. Comparison of FSV PCRV and multi-cavity PCRV

14