11

Development of nuclear power plants in the Atlantic Region

By Dr. T. S. Thompson, P. Eng., Director of Public Affairs, The New Brunswick Electric Power Commission.

The development of interconnections with large neighbouring electrical systems to the north and west has enabled New Brunswick to install large economic generating units, including the Atlantic Region's first nuclear unit, on its electrical system. The site selection and approval process for a nuclear generating station began in 1973 and ultimately led to the commencement of construction at Point Lepreau in May 1975. Construction is more than 60 percent complete with mechanical and electrical installations in the Reactor, Service and Turbine Buildings representing the main activities at the present time. Prince Edward Island has contracted for five (5) percent of the output from Point Lepreau. The extent of further regional involvement in Lepreau and future nuclear development is dependent on the formation of a Maritime Energy Corporation.

L'amenagement d'interconnexions avec les importants reseaux electriques avoisinants au nord et a l'ouest a permis au Nouveau-Brunswick d'installer des gros groupes generateurs economiques, y compris le premier groupe nucleaire de la region de l'Atlantique, sur son reseau electrique. Le choix de l'emplacement et le processus d'approbation pour une centrale nucleaire ont commence en 1973 et ont finalement mene au debut de la construction a Pointe-Lepreau en mai 1975. Plus de 60 pour cent de la construction est terminee et les installations mecaniques et electriques dans les batiments ru eacteur, des services et de la turbine representent les principales activites a l'heure actuelle. L'lle-du-Prince-Edouard s'est engagee a acheter cinq (5) pour cent de la production de Pointe-Lepreau. L'etendue d'une plus grande participation regionale a cette centrale et l'amenagement de groupes additionnels depend de la formation d'une Societe d'energie des provinces Maritimes.

Introduction

Atlantic Canada's first nuclear unit is being built by NB Power at Point Lepreau about 40 km southwest of Saint John, N.B. It is scheduled to be completed by the end of 1980. The unit is a so-called 'standardized" CANDU-600 similar to Gentilly II in Quebec, Cor­doba in Argentina and Wolsung in Korea.

New Brunswick made the decision to introduce nuclear power to the region because of the increase in price and insecurity of supply of oil after 1973; and because the economics favour it, and inter­connections make it technically possible.

The rate of introduction of further nuclear plants to the region is dependent on a number of factors including the extent of development of regional integration, and the potential of other indigenous re­sources .

Interconnections

Prior to 1960, the electric utilities in Nova Scotia, Prince Edward Island, Newfoundland and Labrador, and New Brunswick were operating on a totally isolated basis with the exception of New Brunswick which had established interconnections with two relatively small utilities in the State of Maine in late 1957 and early 1958.

In 1960, for reasons of sharing reserves during emergencies as well as the ability to sell and purchase significant amounts of surplus firm capacity, the then two utilities in Nova Scotia and the New Brunswick utility agreed to interconnect their respective systems with a single 138 kV transmission line. This interconnection agreement contained not only the normal interconnection provisions but provided for a degree of joint planning and sharing of reserves such that it resulted in a reduction of installed capacity on the two systems which was a first in Canada between two power utilities.

While the power utilities in each of the Atlantic Provinces had made good progress toward providing reliable and economic service to their customers, each appeared to recognize in the late 1960's that the things which could have a dramatic effect on the power costs of &eir customers were limited due to the size of the systems. The rt)jective was not necessarily to have lower absolute power rates but lo narrow the gap between the individual provincial systems and those in other more energy-favoured areas of Canada.

New Brunswick's approach to the problem of maintaining competi­tive power rates has been to seek ways to develop interconnections with the large neighbouring systems to the north and west in order that larger, more economic units could be installed in the New Brunswick system itself.

A 350 MW interconnection with Hydro Quebec was brought about by the purchase of substantial amounts of surplus Hydro Quebec capacity and energy available from the early installation of Churchill Falls units. This enabled NB Power to meet its expanding require­ments from Hydro Quebec thereby requiring no units to be brought on-line during the 1971 to 1976 period. The Quebec tie via the world's first commercial High Voltage Direct Current solid state converter station supplied some 40 percent of New Brunswick's requirements in this period.

Discussions with the New England utilities at the same time re­vealed the need for substantial amounts of peaking power as well as a smaller requirement for base capacity during the 1971 to 1975 period. As a result of the determination of specific needs in New England, a package consisting of surplus base capacity of a particular nature existing in both Nova Scotia and New Brunswick was developed and successfully negotiated resulting in the development of a 500 MW tie at 345 kV between the New Brunswick and New England systems.

These two interconnections then gave the ability for New Bruns­wick to install much larger units with their associated economies of scale at the termination of the Hydro Quebec contract in 1976, specifically the construction of 3 - 335 MW oil-fired units at Coleson Cove. Four-ninths of the total 1005 MW output is being sold to New England on a cost-plus arrangement for a period of ten years after which the 335 MW units are an acceptable size on New Brunswick's system.

Interconnection with these large neighbours means that the New Brunswick system can technically withstand interruption in the event of instantaneous loss of 630 MW, the net capacity of Point Lepreau. However, in consideration of long-term replacement of energy and the associated economic loss, N .B . Power is evaluating various ap­proaches to covering the risks of poor unit performance in the early years. The possibilities are to increase reserves or to sell part of its output, similar to Coleson Cove, to either New England or Hydro Quebec.

used on a paper presented at the 92nd Engineering Institute of Canada Annual inference, St. John's, Newfoundland, May 1978. hi. Elec. Ene. J. Vol 4. No 3. 1979

12 CAN. ELEC. ENG. J. VOL 4, NO 3, 1979

The Lepreau project

Need In the period 1960 to 1975, the total in-province demand for

electrical energy increased at the rate of about 12 percent per annum, considerably above the national average. The increase through 1975 to 1983 was projected to average 8.5 percent per annum.

In planning the expansion of power supplies to satisfactorily meet demand beyond 1980, NB Power considered the possibility of large-scale firm purchases, as well as various alternative forms of additional generating capacity. In choosing among such alternatives, NB Power's philosophy has been to select a reliable power supply with the lowest long-term cost to the electricity consumers of New Bruns­wick.

New Brunswick must import oil for its thermal plants at high costs and with low security of supply. Uranium is a Canadian resource and because the economics favour it, even with all the unit output ab­sorbed on the NB Power system with its attendant reserve require­ments, New Brunswick made a decision to proceed with the installa­tion of its first nuclear unit for operation in 1980.

The federal government has recognized the unreliability of im­ported oil supplies and the need for greater self-reliance by its policy to offer loans of up to 50 percent of the capital cost of the first nuclear unit in any province at federal interest rates.

Site selection

Preliminary evaluation studies for the identification of a suitable nuclear power plant site in New Brunswick began in 1973.

Initially, a nuclear plant/heavy water plant complex was visualized for the province and early site evaluation criteria were based on such a facility. Settlement patterns and availability of water supply for cool­ing and heavy water extraction were the primary considerations.

Point Lepreau was among the earliest sites out of more than twenty subjected to preliminary screening. Four sites were studied in detail for the nuclear plant/heavy water plant complex, two in the north of the province on the Bay of Chaleur and two in the south on the Bay of Fundy.

This study evaluated a series of general site selection criteria including public health and safety, public acceptability, socio­economic impact and site ecology through a series of scoring models. The study concluded that, in general, the southern sites were preferred and that Point Lepreau had an advantage in terms of ecological criteria. 1

The heavy water plant site criteria were subsequently dropped from consideration when Atomic Energy of Canada Ltd. decided to build a plant in Quebec.

A study undertaken in early 1974 examined five sites, four in the north of the province and Point Lepreau in the south. Specific studies of cooling-water conditions were undertaken at this stage to determine the feasibility of the once-through cooling option for these sites. Once again, Point Lepreau was preferred, a significant factor in its favour being the greater ability of the cold and turbulent Bay of Fundy with its large tidal range to assimilate the thermal discharge. 2 , 3

Point Lepreau was recommended and Point Caplin and Quinn Point on the Bay of Chaleur were identified as possible future sites. The

Aerial view of construction progress at NB Power's Point Lepreau Generating Station on the Bay of Fundy, 24 miles southwest of Saint John, N.B., July 29, 1978.

THOMPSON: NUCLEAR POWER PLANTS 13

THE NEW BRUNSWICK ELECTRIC POWER COMMISSION SERVICE AREA

T I E T O H Y D R O - Q U E B E C

D A L H O U S I E

C A R A Q U E T

T I E S T O N E W E N G L A N D

U T I L I T I E S

T I E T O P R I N C E

E D W A R D I S L A N D

S- T I E T O N O V A S C O T I A

P O W E R C O R P O R A T I O N

C O U R T E N A Y

C O L E S O N C O V E

> G R A N D M A N A N I S L A N D

A T L A N T I C O C E A N

LEGEND:

PRINCIPAL GENERATING STATIONS

• — I N S E R V I C E

C — U N D E R C O N S T R U C T I O N

HD — H V D C C O N V E R T E R S T A T I O N

I — I N T E R C O N N E C T I O N S

TRANSMISSION LINES 3 4 5 K V

• • • — 3 4 5 K V U N D E R C O N S T R U C T I O N

- ~ — 3 4 5 K V ( O P E R A T I N G A T 1 3 8 K V )

2 3 0 . K V

. . . — 1 3 8 K V

« » — 1 3 8 K V U N D E R

C O N S T R U C T I O N

. - — 1 3 8 K V ( O P E R A T I N G A T 6 9 K V )

14 CAN. ELEC. ENG. J. VOL 4, NO 3, 1979

conclusions of this report as well as the previous site selection studies were reviewed and confirmed by an independent consultant who also examined technical and economic factors. 4

With the selection of Point Lepreau as the site of the province's first nuclear power station in July 1974, two major actions were initiated simultaneously by NB Power in conjunction with the federal and provincial environmental agencies.

First, a baseline study program was initiated to establish and docu­ment the existing environmental conditions of the Point Lepreau area and to provide information for use in the design of the various systems.

Second, a series of Interim Environmental Reports was undertaken for the purpose of progressively assessing the various stages of design and construction.

Superimposed on the above activities was the Federal Environ­mental Assessment and Review Process which had become effective on April 1, 1974 and which was subsequently brought to bear on the project due to the involvement of both federal funds and federal lands. An Assessment Panel was struck and charged with the issuance of guidelines for the preparation of an Environmental Impact Statement on the project.

Since Point Lepreau was the first project ever to undergo the federal EAR Process and, because many of the schedule commitments had been made, the lead times normally expected for environmental assessment were not available. Consequently, NB Power was unable to fulfill all the requirements of the guidelines in time for committed project decisions by February 1, 1975.

The Department of Environment recognized this and the Assess­ment Panel issued guidelines for a Preliminary EIS in November 1974 and NB Power submitted the required document to the Panel in February 1975. 3 The EAR Panel reviewed the submission, arranged for and received additional information, and participated with New Brunswick officials in receiving briefs at a public meeting in early April 1975. 6

The assessment was approved by the Panel in early May of 1975 with a number of recommendations to the Federal Department of Energy, Mines and Resources which were to be subsequently fulfilled. These were addressed in the final environmental report issued in March 1977. 7

This approval then enabled the Atomic Energy Control Board to issue the construction licence for the first unit.

Progress highlights

The Atomic Energy Control Board had granted site approval on October. 18, 1974 for the installation of up to two nuclear electric generating units at the Point Lepreau site.

Following issuance of the construction licence, the first construc­tion milestone was soon reached, namely the pouring of the 1.5 m thick base slab for the Reactor Building. Despite efforts to schedule slip-forming of the reactor building wall for the fall of 1975, labour problems caused it to be postponed until April 1976. The operation was completed in 18 days of continuous concrete pouring.

In the fall of 1976, another construction milestone was reached with the completion of the reactor building inner dome and lower ring beam. The formwork for this dome, 42 m above the base, was supported on structural steel arch trusses. The wood forms supported by these trusses were prefabricated on site in pie-shaped sections curved in two directions.

In the summer of 1977 another major milestone was reached with the delivery from Montreal of the 270 ton stainless steel calandria by roll-on, roll-off vessel at a specially prepared dock at Duck Cove

adjacent to the site. The calandria was placed on a 128-wheel trans­porter and towed the one-half mile to the Reactor Building.

The fall of 1977 saw the completion of the outer dome of the Reactor Building. In the spring of 1978 the cooling water intake and discharge caps were placed and the next major milestone will be completion of the cooling water tunnel system with concrete lining the tunnels.

At the present time (February 1979), construction activity is peak­ing with over 30 contractors working at various on and off-site locations. Construction has passed the 60 percent mark, most of the civil work has been completed, and the main activity is on mechanical and electrical systems. Most of the major components such as the four 19 m long steam generators, the 16 m long pressurizer, the reactivity mechanism deck and the feeder-header frames are delivered to a rail siding six miles from the site and transported via the site access road, a partially upgraded, and partially new road, built to service the site.

Point Lepreau is currently estimated to cost $895 million in total in 1980. This includes all direct costs, engineering and administration, inventories such as heavy water and fuel; plus escalation, interest during construction and certain provisions for a second unit. Point Lepreau.is the Atlantic region's largest construction project and will require some nine million man-hours of onsite labour. Currently over 2000 tradesmen, contractors and NB Power staff are working on site,

Management

The bulk of the design engineering for the station is being provided by three agencies. Atomic Energy of Canada-Limited is responsible for the nuclear steam supply system with Canatom Limited and the N.B. Power Design Department sharing the remainder of the work. Project and Construction Management is being provided by N.B. Power Engineering and Construction Division. All construction work is being performed by contractors for the project.

Site-specific features

Point Lepreau is the first CANDU nuclear station in Canada to be cooled using salt water. This coupled with the fact that provisions have been made for a second unit result in certain site-specific fea­tures.

The triple-shell condenser is designed for a temperature rise of 13°C with a cold water inlet design temperature of 13°C. Titanium tubes have been chosen to resist sea water corrosion. The tubes are designed for a water velocity of about 2 m/s, and the water boxes are neoprene-lined.

In addition to the main sea water circuit to the condensers, there is an additional strained sea-water circuit which takes heat from the lubricating oil coolers, seal oil coolers and other services in the Turbine Building, and from five recirculated cooling water heat ex­changers.

These exchangers dissipate the heat from a number of cooling circuits containing treated fresh water, including emergency core cooling, moderator cooling, shutdown cooling and hydrogen cooling.

Again the tubes are made of titanium, while both the shells and water boxes are of carbon steel coated with an epoxy lining. This sea water is fed by four 33 VS percent duty pumps in the main pumphouse; these pumps have stainless steel housings and impellers.

It should be noted that all radioactive systems are indirectly cooled; i.e. an intermediary inactive fluid, which can be monitored for leak­ages, is used to transfer the heat to the seawater. The inadvertent release of radioactive material into the cooling water, therefore, is extremely improbable.

The Point Lepreau cooling system is designed to minimize the damage to the sea environment around the Point and incorporates

THOMPSON: NUCLEAR POWER PLANTS 15 some of the most advanced environmental engineering concepts in North America. One of the major reasons for choosing the Point Lepreau site was the proximity of deep water with freedom from sea ice, and the good separation of intake and outfall afforded by the peninsula, thus ensuring minimum recirculation of heat. The Bay of Fundy experiences the highest tides in the world, and at Point Lep­reau, the difference between high and low-water levels is sometimes as much as 8.5 m; therefore, unusually deep tunnels are being con­structed. The total length is 1625 m, and the finished diameter of 5.5 m is designed to accommodate two generating units.

The federal Department of the Environment had developed thermal discharge criteria for the nearby Coleson Cove 1005 MW generating station several years earlier and the same criteria were applied at Point Lepreau. Stated simply the criteria require dispersion of a thermal discharge such that no surface area exists which exceeds the ambient water temperature by 5°C or more.

Mathematical modelling indicated that the criteria could be satisfied by a tunnelled submerged discharge with a two-nozzle horizontally discharging end-cap. Submersion was dictated by the required water cover and bottom geology.

The intake criteria were based on protection of the migrating salmon which normally travel in the top 10 m of the water column. Shore protection requirements determined that a tunnelled intake capped by a radial intake structure, located approximately 10 m below mean low water, would provide the necessary environmental protection and reliability.

The purpose of the intake cap was to achieve a horizontal rather than vertical approach flow into the tunnel. This again was based on environmental requirements since it can be shown that fish swimming near the intake would more readily detect and avoid a horizontal flow than a vertical flow.

Recognizing that the intake cap would not be fully effective in preventing the entrainment of at least some fish, the intake forebay was designed to minimize entrapment areas. In addition, the hydraulic approach to the pumphouse will be oblique and fitted with a louvre array, the function of which is to guide fish toward a collection area. From here, depending on the quantities experienced, the fish could be collected in good condition for utilization or even live return to the sea.

Another significant site specific feature is the internal layout of station. The relative orientation of the reactor building, service build­ing and turbine building follows the standard 600 MW design. How­ever, there are significant differences in layout within the turbine and service buildings at Lepreau to meet the requirements of the site and to allow for the addition of a second unit. The control room has been moved to one end of the service building to permit the use of one large control room when the second unit is added. The areas in the service building directly associated with the reactor building, such as the spent fuel discharge systems and storage, moderator purification sys­tem and personnel and equipment airlocks follow the standard pattern. On the other hand, the layout of the rest of the service building is changed to accommodate the position of the Unit No. 2 control room, and the services such as workshops, changing rooms, laboratories and decontamination centres common to the two units.

Maritime Energy Corporation

The New Brunswick/Nova Scotia interconnection has now been developed to two 138 kV lines, and a 345 kV line, currently operat­ing at 138 kV. Interconnection capacity will be 600 MW when the line is operational at 345 KV in 1979.

In September 1977, Prince Edward Island interconnected with New Brunswick via two 21.6 km 3-conductor underwater cables operating at 138 kV. These cables each have a capability of 100 MW providing essentially full back-up. They are also capable of eventual operation

at ±200 kV D.C. which would increase the capability to 300 MW each.

The extent of future participation with Nova Scotia and Prince Edward Island will depend on the outcome of negotiations regarding the formation of a Maritime Energy Corporation.

NB Power played a major role in formulating this concept. NB Power believes that a regional energy corporation with equity partici­pation by the Maritime utilities, together with the federal government, could undertake projects of a type, size and location best suited to the needs of the entire region. Regional co-operation would lead to better energy planning in the Maritimes and increased efficiency in electric generation.

Such a new entity could, through the support and guarantees of the individual utilities and the federal government build, own and operate projects which the utilities would find difficult, if not impossible, to do on an individual basis. The creation of a regional body would mean that Maritime utilities would have access to most economical sources of power available without having to accept disproportionally large financial risks.

In January 1978, federal energy minister Gillespie, and the three Maritime Premiers agreed to go ahead with forming a Maritime Energy Corporation. At that time, it was announced that Phase H studies would be the Corporation's first project if the Fundy Tidal Power Review Board's soon to be released report was favourable.

The report was indeed favourable and in early March, Energy Minister, Gillespie and Premiers, Hatfield and Regan made an announcement to that effect.

Existing external interconnections built and financed entirely by New Brunswick, constitute for the province a valuable and continuing asset, permitting, as I have explained, the addition of large economic generating units in the New Brunswick system, and the purchase and sale of capacity and energy between New Brunswick and the external utilities.

The gains from a Maritime Energy Corporation could be relatively much greater for Nova Scotia and Prince Edward Island, both of who are somewhat isolated from the main stream of large and efficient energy development.

These interconnections and now the Lepreau project, have been undertaken with considerable financial risk but the resultant benefits have been'considerable.

NB Power has offered regional involvement in these major projects but these offers have not been taken up. A common factor seems to be the high financial risks.

To date, Nova Scotia has chosen to continue expansion of its generation requirements through the development of additional coal-fired units. This has come about through the mining of coal reserves in the Lingan area of Cape Breton Island. The full magnitude of the economically recoverable reserves are not known but they are sufficient to have allowed Nova Scotia Power to undertake construc­tion of a 150 MW unit at Lingan for opration in 1979 and they have committed a second 150 MW unit at the same location for operation in 1980. It is expected there will be sufficient coal at Lingan for a total of 600 megawatts of base-load generation'.

Prince Edward Island was offered a five percent share (30 MW) in the output of Point Lepreau either on an equity basis or on an entitlement basis. Negotiations took place between 1974 and 1978 and on December 12, 1978 Prince Edward Island and NB Power announced that contracts had been signed covering the long-term sale and transmission of 30 MW of capacity and energy from Point Lep­reau on an entitlement basis.

16 CAN. ELEC. ENG. J. VOL 4, NO 3, 1979

In consideration of assets in plant and the question of financial risks already assumed by NB Power, conditional upon New Brunswick's support for the formation of a Maritime Energy Corporation is that either the first unit at Lepreau become part of the Maritime Energy Corporation, or the federal government provide performance guaran­tees for the Point Lepreau Generating Station in return for rights to future external interconnections along the New Brunswick border for the Maritime Energy Corporation.

(Note: A memorandum of Agreement between Canada, New Brunswick, Nova Scotia, and Prince Edward Island for incorporation of the Maritime Energy Corporation was signed on February 16, 1979. The agreement calls for the Point Lepreau Generating Station to be purchased from NB Power by the MEC as the MEC's first major project.)

Conclusion

New Brunswick is in a position to play a lead role in further nuclear development. Preferably this would be within the framework of a Maritime Energy Coropration. Development may well prove to be substantial in view of the importance of the technology in reducing the region's dependence on imported oil and hence reducing its vulnera­bility in terms of price and supply of energy.

References

1. MacLaren Atlantic Limited, "Comparison of Environmental Factors Relating to Alternative Sites for a Nuclear Generating Station and Heavy Water Plant — and Addendums", for Department of Fisheries and Environment of the Province of New Brunswick, November 1973.

2. MacLaren Atlantic Limited, "Comparison of Environmental Factors Relating to Alternative Sites for a Nuclear Generating Station, Final Edition — and Adden­dums", for Department of Fisheries and Environment of the Province of New Brunswick, May 1974.

3. MacLaren Atlantic Limited, "Comparative Environmental Study of Intake and Outfall Conditions at Three Alternative Sites for a Nuclear Generating Station, Final Edition — and Addendums", for the Department of Fisheries and Environ­ment of the Province of New Brunswick, May 1974.

4. Montreal Engineering Company Limited, "Review of Reports on Site Selection for New Brunswick Nuclear Plant", July 1974.

5. MacLaren Atlantic Limited, "Preliminary Environmental Impact Statement — Point Lepreau Nuclear Generating Station", for The New Brunswick Electric Power Commission, February 1975.

6. Proceedings of the Public Meeting on the Preliminary Environmental Impact Assessment Statement — Point Lepreau Nuclear Generating Station, April 3 , 1975.

7. MacLaren Atlantic Limited, "Environmental Assessment for the Point Lepreau Generating Station", for the New Brunswick Electric Power Commission, March 1977.

CONFERENCE ANNOUNCEMENT

The Third IFAC (International Federation of Au­tomatic Control) Symposium on Automation in Mining, Mineral and Metal Processing will be held at £cole Polytechnique, Montreal, Quebec, Au­gust 18-20, 1980. Further information can be ob­tained from the Chairman of the National Organi­zing Committee, Professor J. O'Shea, at the fol­lowing address:

Professor J. O'Shea £cole Polytechnique CP. 6079, Succ. "A" Montreal, Quebec H3C 3A7

COURSE ANNOUNCEMENT

A three-day short course on "Digital Communica­tions by Satellite" is to be given at Concordia University, Montreal, September 10-12, 1979.

Further information can be obtained from Dr. V.K. Bhargava at the following address:

Dept. of Electrical Engineering Concordia University 1455 de Maisonneuve Blvd. West Montreal, Quebec H3G 1M8 Tel: (514) 879-4597