ML20137J372
| ML20137J372 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 01/17/1986 |
| From: | Devincentis J PUBLIC SERVICE CO. OF NEW HAMPSHIRE |
| To: | Noonan V Office of Nuclear Reactor Regulation |
| References | |
| SBN-928, NUDOCS 8601220416 | |
| Download: ML20137J372 (13) | |
Text
1.
SEABROOK STATION Engineering Office Pub 5c service of New Hampshke Now Hampshire Yonkee Division January 17, 1986 SBN-928 T.F. B7.1.2 United States Nuclear Regulatory Commission Washington, DC 20555 Attention:
Mr. Vincent S. Noonan, Project Director PWR Project Directorate No. 5
References:
(a) Construction Permits CPPR-135 and CPPR-136, Docket Nos. 50-443 and 50-444
Subject:
Revisions to FSAR Section 8.2 - Off-Site Power System
Dear Sir:
FSAR Section 8.2.1 states that the Seabrook to Newington and Seabrook to Tewksbury 345 kV transmission lines will be in service prior to Unit 1 core loading; the third line, Seabrook to Scobie Pond, will be in service prior to Unit 2 going on line.
However, regulatory appeals at the state level have delayed the completion of the Seabrook to Tewksbury line so that it will not be available for Unit 1 core loading. The Seabrook to Scobie Pond line has been completed and will be available to provide the second independent source of off-site power to Seabrook Unit 1.
In the FSAR we make reference to stability and power flow studies to support the requirements of GDC 17.
However, these studies represent the transmission line configuration stated in FSAR Section 8.2.1.
Additional power flow and stability studies were therefore performed to identify any additional system requirements and to demonstrate that Seabrook Unit 1 connected to the transmission grid by the Seabrook-Scobie Pond and
, Seabrook-Newington 345 kV transmission lines can meet all the applicable criteria.
8601220416 860117 PDR ADOCK 050 3
o P.O. Box 300 Seobrook. NH 03874. Tetophone (603) 474-%21
t United States Nuclear Regulatory Commission Attention:
Mr. Vincent S. Noonan Page 2 The results of the additional studies and the changes in the transmission line availability have been incorporated in the attached revised sections of the FSAR'(Attachment 1).
These will be incorporated into the FSAR by a future amendment.
Very truly yours, John DeVincentis, Director Engineering and Licensing Attachment cc: Atomic Safety and Licensing Board Service List I
i b
i
William S. Jordan, III Donald E. Chick Diane Curran Town Manager Harmon, Weiss & Jordan Town of Exeter 20001 S. Street, N.W.
10 Front Street Suite 430 Exeter, NH 03833 Washington, D.C.
20009 Brentwood Board of Selac cmen Ro be rt G. Perlis RED Dalton Road Of fice of the Executive - Legal Direc tor Brentwood, NH 03833 U.S. Nuclear Regulatory Commission
~ Washington, DC 20555 Richard E. Sullivan, Mayor City Hall Robert A. Backus, Esquire -
Newburyport, MA 01950 116 Lowell Street P.O. Box 516 Calvin A. Canney Manc hester, NH 03105 City Manager City Hall Philip Ahrens, Esquire.
126 Daniel Street Assistant Attorney General Portsmouth, NH 03801 Augusta, ME 04333 Dana Bisbee, Esquire Mr. John B. Tanzer; Assistant Attorney General Designated Representative of Office of the Attorney General the Town of Hampton 206 State House Annex 5 Morningside Drive Concord, NH 03301 Hampton, NH 03842 Anne Verge, Chairperson Roberta C. Pevear Board of Selec tmen Designated Representative of Town Hall the Town of Hampton Falls South Hampton, NH 03827 Drinkwater Road Hampton Falls, NH 03844 Patrick J. McKeon Selectmen's Office Mrs. Sandra Gavutis 10 Central Road Designated Representative of Rye, NH 03870 the Town of Kensington RFD 1 Ca role F. Kagan, Esquire East Kingston, NH 03827 Atomic Safety and Licensing Board Panel U.S. Nuclear Regulatory Commission Jo Ann Shotwell, Esquire Washington, DC 20555 Assistant Attorney General Envi ronmental Protec tion Bureau Mr. Angi Machiros Department of the Attorney General Chairman of the Board of Selectmen One Ashburton Place, 19th Floor Town of Newbury Boston, MA 02108 Newbu ry, MA 01950 Senator Gordon J. Humphrey Town Manager's Office U.S. Senate Town Hall - Friend Street Washington, DC 20510 Amesbury, MA 01913 (ATTN: Tom Burack)
Senator Gordon J. Humphrey Diana P. Randall 1 Pillsbury St reet 70 Collins St reet Concord, NH 03301 Seabrook, Nll 03874 (ATTN: lie rb Boynton)
SBN-928 ATTACHMENT 1 Revised FSAR Section 8.2 Excerpts, Seabrook Station
SB 1 & 2 FSAR 8.2 0FFSITE POWER SYSTEM 8.2.1 Description The transmission grid connections which provide offsite power for the two Seabrook Station consist of three 345 kV transmiscion lines, as units at shown in Figures 8.2-1, 8.2-2, and 8.2-3.
These lines are designed and to provide the electrical and structural independence necessary to built insure continuity of offsite electrical power to the station.
At Seabrook Station, the three lines terminate at separate terminating From the terminating structures each circuit is routed in structures.
metal-enclosed, SF6 gas-insulated bus to a common switching station, T
1 as shown in Figures 8.2-7 and 8.2-8.
T of e thr trans 'ssion l' es (th ewingt and T ksbur line il e in rvice ior to it Ic e loadi The ird
'ne (
Scobie d) wi be p1 ed in s vice pr* r to Un' 2 goi on l' e.
1 S.2.1.1 Transmission Lines 1
ssionl'ineridts-o-wayi of r ason ly FThe op k pby of e 345 trans f
dir tion for f t ar s or 1 rollin ills. One l' e runs /tn a n rther appro tmately miles nd ter nates t Newi con Ge erati Sta on i New' gton, w Hamps re.
seco line r s in wester y di ectio for roxim ly five les a then ers sou for proxi tely 5 mi s,
termip fing at Te sbury ub s ta ti n in Tew sbury, fassac sett Th thi d linVruns in a sterly irectio for app oxima ly 28 les d te ina es JVScobie Pond ub s ta t ' n in L donderry, New mpshir.
The two 345 kV lines from Seabrook to Scobie Pond and from Seabrook to Tewks-bury are on separate towers but share the same right-of-way for approximately five miles as shown in Figure 8.2-1.
The br. lance of the Tewksbury line is shown in Figure 8.2-2.
Both the Scobie Pond and the Tewksbury transmission lines utilize wood or steel H-frame type structures, with two steel H-frame structures in parallel See detail B of Figure 8.2-4 on the common portion of their rights-of-way.
The steel angle structures for typical parallel 345 kV H-frame structures.
necessary for those portions of the lines are similar to that shown in detail C o f Figure 8.2-4.
As noted on Figure 8.2-1, the spacing of the structures on the parallel lines is 85 feet center-to-center. The combination of 85 in the design of the steel structures foot separation and the safety factors insures complete electrical and physical separation of the two transmission lines along the five mile section of conanon right-of-way.
The Newington line is on an entirely separate right-of-way, as shown in The transmission line from Seabrook to Newington Station Figure 8.2-3.
in detail A of Figure uses single pole steel structures similar to that 8.2-4 and H-frame type structures similar to those shown in detail B of j
l j
j Figure 8.2-4.
j v
8.2-1
4 h Sc.ti 1 It has been anticipated that two of the three transmission lines (the Newington and Tewksbury lines) will be in service prior to Unit I core loading. The third line (to Scobie Pond), would have been placed in service prior to Unit 2 going on line. Appropriate power flow and stability studies were performed for this line configuration as shown in Section 8.2.2.3 of the FSAR. Subsequent to these studies and because of local regulatory difficulties, completion of the Seabrook-Tewksbury line has been delayed and, therefore, it will not be available for Unit 1 core loading. The Seabrook to Scobie Pond line has been completed and will be available to provide the second independent source of off-site power to the Seabrook Unit 1.
Additional power flow and stability studies were performed to identify any additional system requirements and to demonstrate that Unit 1 connected to the transmission grid by the Seabrook-Scobie Pond 345 kV line and Seabrook-Newington 345 kV line can meet all applicable criteria. The results of those additional studies are shown in Section 8.2.2.3.
I S C,, t h The topography of the 345 kV transmission line rights-of-way is of reasonably flat areas or low rolling hills.
The Newington line runs in a northerly direction for approximately 18 m..les and terminates at Newington Generating Station in Newington, New Hampshire. The Tewksbury line runs in a westerly direction for approximately five miles and then veers southerly for I
approximately 35 miles, terminating at Tewksbury Substation in Tewksbury, Massachusetts. The Scobie Pond line runs in a westerly direction for approximately 28 miles and terminates at Scobie Pond Substation in l
Londonderry, New Hampshire.
Sl1 1&2 D
s FSAR 8.2.2.3 Power Flow and Stability Studies 4.
1980 Studies for Unit 1 and Unit 2 Operation j
B.
Seabrook Station Units 1 and 2 Transient Stability and Power Flow Studies (References 6 and 7) have been performed to determine the effect of the Seabrook Station and its associated facilities on the reliability of the The current studies for Unit 1 interconnected transmission system.
dif fer from previously performed studies, which were included in the Seabrook PSAR, due to the revised order in which the transmission lines are being The transmission lines associated directly with both Units 1 and 2 built.
have not changed, but the interconnected transmission system representation has been updated as applicable.
The studies reported in References (6) and (7) update similar studies submitted to NEPOOL (New England Power Pool) in 1974 and serve to reconfirm the power Modifications were made to the transfer levels presented in those studies.
load, generation and transmission representations based on the most up-to-date The studies were performed in accordance estimates for the study years.
with the NEPOOL and NPCC (Northeast Power Coordinating Council) reliability System performance was evaluated at power transfer levels that criteria.
Trans fer levels at or above those presented could be reasonably expected.
in the 1974 studies were investigated and system requirements necessary to achieve these transfer levels were determined.
System Representation and Methodology a.
The transient stability study was conducted using the Westinghouse Electric Corporation's Transient Stability and Power Plow Programs.
A detailed network representation of Nova Scotia, New Brunswick, l
A less detailed network repre-New England and New York was used.
sentation of Ontario Hydro, P.J.M. (Pennsylvania, New Jersey, Cases Maryland) and systems to the west and south was utilized.
studied included consideration of delayed clearing of faults, inoperative circuit breakers, and unsuccessful attempts to reclose a circuit breaker subsequent to initial clearing of a fault.
The need for dual high speed relaying systems and required modes individual terminals were also investigated.
of reciosing at The power flow study was conducted using the Philadelphia Electric A detailed network representation was utilised Power Flow Program.
for New England and a simplified network representation was utili-zed for New York and New Brunswick.
A 45 and 95 percent winter peak load level was studied for both study years for both the transient stability and the power flow The studies included cases stressing intra-pool power studies.
trans fers. Cases simulating post fault power flow conditions Figures were run for the majority of the stability cases studied.
8.2-11 and 8.2-12 are switching diagrams of the portion of the 345 kV transmission system most closely tied to seabrook for the
(
two study years.
8.2-18
l A.
1985 Studies for Unit 1 Operation With Seabrook to Newington and Seabrook to Scoble Pond 345 kV Line Configuration As mentioned under Section 8.2.1, the construction of the Seabrook to Tewksbury 345 kV transmission line has been delayed due to local regulatory difficulties, so this line will not be available for Unit 1 core loading as originally anticisated. The Seabrook to Scobie Pond line has been completed and will provide the second independent source of off-site power to the Unit as well as will provide a second path for Seabrook power to flow into the transmission grid.
The stability studies performed in 1980 (References 6 and 7) do not represent the line configuration that will be in existence for Unit 1 operation (i.e., Seabrook to Newington and Seabrook to Scobie Pond).
Therefore, new studies (Reference 13) were performed to demonstrate that Seabrook Unit I connected to the transmission system by the Seabrook to Scobie Pond 345 kV line, and the Seabrook to Newington 345 kV line can meet all the applicable criteria aid satisfies the requirements of GDC 17.
These new studies for Unit 1, supersede the applicable portions of the 1980 studies for Unit 1 operation.
These studies, reported in Reference 13, were performed in accordance with NEPOOL and NPCC reliability criteria.
a.
System Representation and Mathodology The basic transmission network used for this study was developed by the Transmission and Stability Task Forces of the NEPOOL Planning Committee for stability studies. Changes were made to simulate the year 1986. A 45 percent and 75 percent summer peak load level was represented based on the " April 1985 NEPOOL Forecast Report of Capacity, Energy, Load and Transmission."
9 v1 N k Wh.e4 ')
A detailed network representation of Nova Scotia, New Brunswick, New England and New York was used. A less detailed network I
representation of Ontario Hydro, PJM (Pennsylvania, New Jersey, Maryland) and the Interconnected Systems Graup was utilized. The study was performed by using the Westinghouse Electric Corporation "Westcat" Transient Stability and Power Flow Programs.
Thermal transfer limits as determined by NEPLAN were taken into consideration for this time period assuming the Seabrook-Tewksbury line is not in service. Stability testing was done at these transfer limits as discussed in Reference 13.
Several different generation dispatches were tested to determine how these different dispatches effect system performance.
Figure 8.2-11A represents the switching diagram of the portion of the 345 kV transmission system most closely tied to Seabrook for this particular study, b.
Results and Conclusions These studies have demonstrated that Seabrook Unit 1 connected to the transmission system by two 345 kV lines (Seabrook-Scobie Pond and Seabrook-Newington) can meet the NEPOOL " Reliability Standards for the New England Power Pool" and the NPCC " Basic Criteria for Design and Operation of Interconnected Power Systems."
f I
With proper system operating procedures, stable operation of the interconnected power system can be maintained and availability of the off-site power supplies to the Seabrook Unit I will not be impaired.
l Furthermore, load flow studies performed demonstrate the power system can be operated such that loss of the Seabrook to Scobie Pond line, Seabrook to Newington 345kV line or for other representative line contingencies, all voltages and line loadings can be within required limits.
It is expected that the Seabrook to Tewksbury line will be completed at some later date. Completion of this line will allow more economic operation of the generation system as well as allow significant flexibility in system operation.
I
4 SB t&2 FSAR As a result of the transient stability studies, it was determined that, in addition to the three 345 kV transmission lines terminating at Seabrook Station, an additional 345 kV circuit breaker will be required at Colburn Road Sut, station (Milford, New Hampshire) av= ram stability with both Seabrook units in operation.
to n aan ra k(.. G~M W).a m)(References 8 and 9) have demonstrated Studies conducted by NPCC the split of power on the New England to New York tie lines that is relatively insensitive to the location of generation outages in New England. NEP00L studies have demonstrated that New England can pick up the loss of the Millstone complex (2630 MW) from New York and that no reliability problems exist. Since Seabrook is a 2300 MW facility, the loss of Seabrook Station is a less severe disturbance than the loss of the Millstone complex. Prior to the loss of the two Seabrook units, the power flow from Northern New England to Southern New England would be on the order of 2000 MW.
Upon loss of the two Seabrook units, there would be a decrease in the Northern New England to Southern New England power flow of approximately 2300 MW.
As shown by the studies modeling the loss of Millstone, New England can make up this loss (without system reliability problems) by importing 2300 MW from New York.
It is therefore concluded that loss of preferred power supply to the Seabrook nuclear units would not occur as a result of the loss of one or both Seabrook nuclear units.
gI g
NPCC has performed a study (Reference 10) to investigate the ef fect that the dropping of a large portion of load might have on the interconnected system. The load dropped (2600 MW), consisted of the Northfield Mountain Pumped Storege Plant (1000 MW), the Bear Swamp Pumped Storage Plant (600 MW) in Massachusetts, and Gilboa Pumped Storage Station (1000 MW) in New York, all operating in the pumping mode. The study, which was done on a large 1975 system representation, indicated no system break-up.
Frequency decay rates, in the event of a sudden generatior./ load imbalance, based on analysis and experience in the NPCC system (of which the New England 345 kV grid is part) are predicted to be less than the maximum credible frequency decay rates used by Westinghouse to determine loss of flow transients caused by fre-quency decay events. Although it is not possible to predict with certainty the boundaries of electrical islands, should they occur, computer studies for the NPCC system (Reference 11), taking into account the NPCC underfrequency load shedding program, have shown that the frequency decay does not exceed 4 Hz/second.
Based on the results of the studies performed, it is concluded that the generation at Seabrook Station with Unit 1, and with both Units 1 and 2, together with the facilities required to inte-grate this generation into and reinforce the transmission grid
(
meet the NEPOOL " Reliability Standards for the New England Power 8.2-20
Since the completion of the 1980 studies, increased transfers of economic energy from the Midwest and Canada have heavily loaded the Transmission Currently, studies System in the Northeastern area of the United States.
are in progress by several NPCC and PJM companies to assess the effect of loss of large amounts of generation in the New York and New England Plans will be formulated to allow for continued reliable areas.
operation of the power system.
SB 1 & 2 FSAR L-Pool" (Reference 3) and the NPCC " Basic Criteria for Design and Operation of Interconnected Power Systems" (Reference 2).
As the system configuration warrants, NEPOOL periodically assesses the New England bulk power supply system on a near term basis with regard to disturbances associated with line out conditions in accordance with both NEPOOL and NPCC criteria. These studies determine any required remedial action to assure that system operation is in conformity with the criteria and form the basis of actual operating procedures.
8.2.3 Re ference s 1.
" Bulk Power System Protection Philosophy", Northeast Power Coordinating Council.
2.
" Basic Criteria for the Design and Operation of Interconnected Power Systems", Northeast Power Coordinating Council.
3.
" Reliability Standards for the New England Power Pool", New England Power Pool.
4.
ANSI C2, " National Electrical Safety Code.".
5.
" Code for the Installation and Maintenance of Electrical Transmission Lines", Commonwealth of Massachusetts (applies within Massachusetts only).
6.
Public Service Company of New Hampshire, Seabrook Station, Unit No. 1 and Unit No. 2 Transient Stability Study - January 1980.
7.
Public Service Company of New Hampshire, Seabrook Station, Unit No. 1 and Unit No. 2 Power Flow Study - January 1980.
8.
NPCC Report: " Analysis of the NPCC 1985 Transmission System" - June 1976; NPCC Working Group No. 17.
9.
NPCC Report: " Analysis of the NPCC 1983 Summer and 1983/4 Winter Trans-mission System" - July 1979; NPCC Working Croup No. 27.
10.
NPCC Report: " Study of the Use of Pumped Storage Units for Load Shedding by NPCC Task Force on Systems Studies" - April 1974; NPCC Wcrking Group No. 16.
11.
NPCC II Joint Working Group Report - September 1970 12.
Seabrook Generator Circuit breaker Qualification Test Reports and Analyses.
_^%
13.
Public Service Company of New Hampshire, Scabrook Station, Unit No. 1 i
f' t
Load Flow and Transient Stability Study, December 1985 (analysis befors completion of Seabrook to Tewksbury transmission line).
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