ML17339A580
| ML17339A580 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point, Saint Lucie  |
| Issue date: | 10/05/1977 |
| From: | Lear G Office of Nuclear Reactor Regulation |
| To: | Robert E. Uhrig FLORIDA POWER & LIGHT CO. |
| Shared Package | |
| ML17207A819 | List:
|
| References | |
| NUDOCS 8002150518 | |
| Download: ML17339A580 (16) | |
Text
Reference 8
UNITED STATES NUCLEAR REGULATORY COhlMISSION liYASHINGTON,D. C. 20555 October 5, 1977 Dockets Nos.
50-250 50-251 and 50-335 P<
r
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Florida Power 5 Light Company ATTN:
Dr. Robert E. Uhrig
. Vice President P. 0.
Box 013100 Miami, Florida 33101 Gentlemen:
ttlce Pre;igerIg fsIlc,'52, err;,
The Florida Power and Light Company (FPSL) submitted a report entitled, "Report on System Disturbance May 16, 1977," dated June 29, 1977 for review by the NRC staff.
This report provides details of the events and causes of the system outage that resulted in loss-of-offsite power to the Turkey Point and St. Lucie Stations.
It also describes certain corrective actions recommended by FPKL.
Me have reviewed the informa-tion provided and determined that certain additional information is required for completion of our evaluation.
Please provide your written response to the enclosed request for additional information within 30 days of your receipt of this letter.
Should you have any questions on,this matter, please contact us.
Sincerely,
Enclosure:
Request for Additional
'nformation George Lear, Chief Operating Reactors Branch 43 Division of Operating Reactors cc:
See page 2
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Florida Power 8 Light Company CC" Mr. Jack R.
- Newman, Esquire Lowenstein,
- Newman, Reis
& Axelrad 1025 Connecticut Avenue, N. H.
Suite 1214 Washington, D.
C..
20036 Environmental 8 Urban Affairs Library Florida International Universi.ty Miami, Florida 33199
Enclosure RE UEST FOR ADDITIONAL INFORMATION FPL REPORT ON SYSTEM DISTURBANCE MAY 16, 1977 DOCKET NUMBERS, 50-250,
- 251, AND 335 The NRC staff and its consultants have been reviewing the Florida Power and Light (FPL) report dated June 29, 1977, entitled, "Report on System Disturbance May 16, 1977."
The information provided in the report is not adequate for us to complete our evaluation of the events that occurred during the FPL system.disturbance of May 16, 1977,. and th'eir effects on the Turkey Point and St. Lucie nuclear power stations.
In addition to our review of the subject report, we have reviewed and are utilizing information contained in the following reports in our review effort to evaluate the May 16th disturbance:
Stone and Nebster report dated May 18, 1973, entitled, "Re'port to Florida Public Service Commission on FPL Electric Power System Disturbance April 3.and 4, 1973"; and b.
FPL report to the FPC dated July 19, 1974, entitled, "Report: on System Outage June 28, 1974."
1.0 So that we may better understand the causal relationships between the events that occurred on May 16, 1977, please provide the following information:
1.1)
A time trace of the real power loading on the Ft. Myers-Ranch 240 kV line for the time period 10:08-10:24 am; 1.2) The normal rating of this line (W, MVA);
1.3) The long time and short time emergency ratings; 1.4) If the ratings are given in MW, indicate the power factor to which they apply; 1.5) The MVA load (or the power factor) on the line when it relayed open; 1.6) If the information in Items 1.4 and 1.5 is not available, provide power factor or equivalent information at points as close to this line as available; and 1.7) The line loading information (power, power factor, etc.)
on this line for each occasion in the past when it relayed open.
2.0 It is the contention of FPL that the relaying of the Ft. Myers-Range line was not necessarily a consequence of events brought on by the Turkey Point, Unit 3 scram.
The following is an excerpt from. ANSI
- 0 5EP. 2 S 1977 d 379-1972, Draft American National Standard, IBEE Trial-N41-2, ZEEE Std 3
r lure Criterion to Use ux e
or G
d f the Application of the Single Fai ur stems.
Nuclear Power Generating Station Protection Sy "3.
Classification of Single Failures 3.1 Classifications.
To clarify the sing1e-failure concep t and to provide a basis for common under-e sin le s an ing t
d'ng among the users of the.s guide, g
I have been grouped xnto three typ s.
es.
Since a~ ures he sin le-failure failures within the meaning of t<<e sang criterion, regardless of whether or not they violate the single-failure criterion, are classified as follows.
A d tectable failure resulting from one T
e I:
e ec
~ault.
d ent or module or from a circuit Note:
Examples of circuit -faults inclu e s or d
and the applica-
'rcuits open circuits, grounds, an tion of the maximum credible a.c. or d.c.
p
.c.
otential.
T e 2:
u xp M lt le detectable failures resulting from t
a single cause external to the protection system.
)e 3:
Multiple.detectable failures resulting from I
'thin the protection system."
a single cause wi N41.2 a lies not to the grid but While the above excerpt from QS pp t
to the protection sys s stem of a nuclear power plant, xt xs e
m we have found for interpretation of relevant authoritative statement we ave oun the meaning of single or multiple failures (contingencies d information, please provide the With the above citation as background xn following information:
ood of a causal relation between the Ft. Myers-Ranch 2.1, If the likelihoo o
a U t 3 scram were conceded, wou c
the two events constituted and the Turkey Point, nest scr would FPL continue to represent t at e
a double rather than a single contingency?
or our response to Item 2.1.
2.2 Provide a discussion of the bases for y PL's consultant Stone and webster entitled, F o 9 3 port o F L's ons R port to FIorx P
x S
System Disturbance April 3 and 4, 1973," date ay the following recomm ndation:
e made to establish and maintain digital dels would provide infor-lit models of the orz. a sentxng current conditions.
These mo e s wo ator b I t limits and other system mation to the operator ators on stabs z y im dela s or equipment outages.
limitations,imposed by construction de ays or eq
- 0 Stability and load flow studies should be conducted for 1974 and 1975 conditions to check the effectiveness of corrective measures such as additiona1 load shedding, blocking of reclosing and other aspects of line relaying and system design.
'Ihese studies should include off-peak as well as peak load conditions."
Considering the above cited recommendation, what studies were made to determine the condition of the system with the outage of Turkey Point, Unit 4 and the 500 kV line prior to the shutdown of these two facilities?
Specifically, 3.1)
What information did the studies provide relative to stability limits and other system limitations?
3.2) If the studies were not made,.why not?
3.3) If they were made and did not show the vulnerability of the system to a failure, why did they not?
3.4) If they were made and did show the system vulnerable to a failure, what precautionary measures were adopted?
.0 Following the June 28, 1974 power outage, FPL filed with the FPC
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a report entitled, "Report on System Outage June 28, 1974," dated Duly 19, 1974.
The following'is a direct quote from that report:
"2.
At Turkey Point Plants on Units 3 and 4 the following measures are being undertaken:
a.
To 'improve unit trip analysis:
a-1.
A digital data processing system which includes discrete time sequence of events capability is now on order and should be operational this year.
a-2.. A continuous recording high speed oscillograph
's on order for the nuclear units to record events p.ior to, during, and after a disturbance."
Accordingly, please provide the following information:
4.1) The frequency versus time information at the Turkey Point bus and at the St. Lucie bus at least to tenth of a second accuracy for the ten second period following the scram of each reactor; and
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- 4. 2) The same information requested in (4.1) including M!7 production versus time and HVAR production versus time at the Turkey Point bus and the St.
Lucie bus for the time period 10:08 to 10:24, and shortly before 10:08.
This information may be provided on a coarser scale.
5.0 Regarding the Hay 16, 1977 system outage, the report states:
"0 eratin Philoso hy The Opexating Committee of the Florida Electric Power Coordinating Group coordinates the operation of all systems with Peninsular Florida and establishes operational guides, practices and procedures on spinning reserve, loading shedding and emergency operating procedures.
The Florida systems are designed and operated to allow loss of the largest unit in the state without loss of load.
The required spinning reserve to accomplish this is allocated among systems on the basis of unit size and system peak load.
Distxibution of the spinning reserve allocation within an individual system is a function of area protection, unit availability and economics."
The above quote appears to imply that FPL may be relying for paxt of its spinning reserves on neighboring utilities.
Provide the following information:
5.1)
A clear definition of FPL's system requirements on spinning reserves, distinguishing between tie-line imports and spinning reserves; and S. 2)
A copy of the guidelines established by the Operating Committee of the Florida Electric Power Coordinating Group relating to practices and procedures on spinning reserves, load shedding, and emergency operating procedures.
- 6. 0 The following recommendations were included in the 1973 report:
"FPL should continue to put a high priority on transmission additions to strengthenties between the southern area and the rest of the Florida systems.
Construction of transmission lines in southexn Florida has been delayed by environmental considerations and labor problems.
Further delays will affect the reliability of the FPL system.
A strong 500 kV system with ties to Georgia, which is now in the planning stages, should be pursued with due regard to development of proper systems within Florida and Georgia in
~ conjunction with interstate ties.
)t i
l,
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SEP. 2 8 )977 Discussions between Southern Company and the Florida companies concerning additional 240 kV interstate ties should be given urgent priority with the objective of increasing the emergency interchange capability to Florida from Southern Company to at least 800 i~S by 1976.
This would allow loss of the largest unit without causing isolation of peninsular Florida.
~ The addition of these 240 kY lines should be considered an interim measure and should not affect the longer range plans for 500 kV ties.."
The following recommendation is included in the h/ay 16, 1977 report:
"Recommendation:
expansion as an alternative to increased spinning reserve."
Considering the above recommendations, please provide the following information:
6.1) 1&at is the current status of the 500 kV system of interties with Geoergia which was in the planning stage according to the 1973 t
report?
6.2) Is there an emergency interchange capability of 800 MW from Georgia to Florida as projected for 1976?
6.3) Are the Georgia - Florida interties emergency or economic
'in nature?
6.4) Are the ties set to open at such a (relatively) high frequency that they are of little use in a large disturbance (such as
- 1973, 1974, 1977) and that in a moderate disturbance they might even make things worse by opening when only a relatively small imbalance exists?
6.5) Furnish a description of the organization of Power Coordinators and Dispatchers which includes the following:
a)
The number of power coordinators and dispatchers for each shift; b)
How they interact in emergency situations and with other utility power coordinators and dispatchers; and c) Pihat telemetered data and what communications facilities are available to them -- especially for communicating with quick-start facilities and with maintenance crews.
7.0 The following recommendations relating to protective relays were included t
in the 1973 report:
<l
SEP. 2 8 1977 "As long as the Florida Companies must trip units automatically on underfrequency, FPL should revise their relay schemes so that each set of relays trip only one'nit unless the total amount of generation to be tripped by one set of relays is less than 250 W.
Each scheme as a minimum should have two relays both set to pick
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up at 58 cycles with their contacts in series so that both must operate to trip the unit.
C Consideration should be given to adding out-of-step relays to 115 kV, 13S kV, and 240 kV circuits to block reclosing on trips due to s tability swings..
FPL should undertake a thorough review of its relaying philosophy and protective schemes 'to ensure that this important part of its system design provides the highest possible degree of reliability and security."
The following actions being taken by FPL were included in the 1974 report:
0 "3. 'elays for out-of-step detection and blocking of reclosure of lines tripped due to stability swings were to be installed on 40 major line terminals.
Engineering is in progress and is expected to be completed in six to nine months."...
"5.
A 7ask Force has been formed with members from System Operations, System Protection, Power Resources, Engineering and System Planning to continue investigation of the disturb-ance and follow through with corrective measures.
Some specific means under investigation include:"...
"b.
implementation of measures to block reclosing following out-of-step trip.
c.
Studies are being made to determine the requirements for high speed ground backup relaying to assure that faults will be. cleared fast enough to prevent system instability."...
"8.
Relay settings are being examined for proper coordination on the affected lines.
Preliminary analysis indicates correct coordination for the ground backup relays presently in service."
f I
We following actions being taken by FPL which are included in the 1977 report:
"2.
S stem Plannin /System Protection/General Engineerin Conduct review of current practices and designs relating to high speed reclosing of transmission lines."
V
' Considering the above recommendations and actions, please provide the following information:
f" SEP. 2 8 ig7$
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7.1) Describe how, to what extent, and when the past recommendations on relays were implemented?
7.23 What effect did that implementation have on the ofay 16, 1977 disturbance?
7.33 Discuss the significance of the Turkey Point, Unit 4 and the 500 kV Orange River-Andytown line equipment outages to this event and explain why it is not necessary to include discussion of them in the "Report on System Disturbance hfay 16, 1977."
Cl