ML20206S168
| ML20206S168 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 07/02/1986 |
| From: | DETROIT EDISON CO. |
| To: | |
| Shared Package | |
| ML20206S166 | List: |
| References | |
| NUDOCS 8607070303 | |
| Download: ML20206S168 (11) | |
Text
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TABLE 3.3.3-2 (Centinued)
EMERGENCY CORE COOLING SYSTEM ACTUATION INSTRUMENTATION SETPOINTS E ALLOWABLE TRIP SETPOINT VALUE
! ! TRIP FUNCTION
- 4. AUTOMATIC DEPRESSURIZATION SYSTEM b a. Reactor Vessel Low Water Level - Level 1 > 31.8 inches * > 24.8 inches
- b. Drywell Pressure - High 31.68psig 51.88psig
" c. ADS Timer < 105 seconds < 117 seconds
- d. Core Spray Pump Discharge Pressure - High [145psig, increasing [125psig, increasing
- f. Reactor Vessel Low Water Level - Level 3 > 173.4 inches * > 171.9 inches
- g. Manual Initiation HA NA S. LOSS OF POWER Division 1
(Loss of Voltage) (Division 1 and 3033 volts 3033 i 60.7 volts Division 2) b. 120 V Basis -
87.5 volts 87.5 i 1.75 volts 5:' c. 2 sec time
- delay 2.0 1 0.1 sec time delay 5;* Division 2 i y a. 4.16 kV Basis -
3078 volts 3078 i 61.6 volts
- b. 120 V Basis -
88.8 volts 88.8 i 1.78 volts
- b. 4.16 kV Emergency Bus Undervoltage c. 2 sec time delay 2.0 1 0.1 sec time delay (Degraded Voltage) (Division 1 and Division 1 Division 2) a. 4.16 kV Basis - 3952 1 W 0 3952. -NO2- volts -3702 1 74.0 volts
- b. 120 V Basis - 4.o i 2. a 184.0 -196:6-volts 1^5.8 1 2.14 volts
- c. -1977- sec time 4 4 0 1 2.2.
44.0 delay -la.7 1 1.0 sec time delay Division 2
- B607070303 860702 O a. 4.16 kV Basis -
PDR ADOCK 05000341 ij 3702 volts 3702 1 74.0 volts P PDR v 120 V Basis -
b.
106.8 volts 106.8 i 2.14 volts
- c. 21.4 sec time delay 21.4 i 1.07 sec time delay I " See Bases Figure B 3/* '-1.
]
- Suppression pool water level instrument zero is 14'6" above bottom of torus at elevation 557'0".
U .
A3-1 Attachment 3 Chronology of Events May 27, 1986 Potential undervoltage condition identified during Calculation Update Program.
June 3, 1986 NRR & Region III informally notified of condition.
June 4, 1986 Analysis of vendor information complete.
DER written.
10CFR50.72 notification made on ENS.
June 7, 1986 Letter indicating intent to request Emergency Technical Specification Amendment telecopied to NRR PM.
June 11, 1986 Formal request for Emergency Technical Specification Amendment submitted.
June 12, 1986 Formal request for Emergency Technical Specification Amendment docketed.
June 13, 1986 Request for Emergency Technical Specification Amendment denied.
Preparation of standard Technical Specification Amendment begins.
Received telefax of NRR letter, dated June 13, 1986, granting relief to continue outage and requesting a meeting to discuss this issue.
June 17, 1986 Received Region III telefax, dated June 13, 1986, granting relief to operate while the plant is in modes 4 and 5.
June 19, 1986 Meeting between Detroit Edison and NRR in Bethesda, MD l
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A4-1 Attachment 4 Summary of Design Calculations Design Calculations Involved DC 968 Sizing of Thermal Overload Heaters, Starters, Fuses, Verification of Motor Tern nal Voltage and Verification of Penetration Protection for Intermittent Duty Motors (Motor Operated Valves) (Covers both Class lE and BOP MOVs).
DC 969 Sizing of Thermal Overload Heaters, Starters, Fuses, Verification of Motor Terminal Voltage and. Penetration Protection for continuous Duty Motors fed from Motor Control Centers (Covers both Class lE and BOP Motors).
DC 835 System Voltage Study DC 919 Degraded Grid Relay Setpoint Design Calculation Methodology The reason for the setpoint change is the result of changing two assumptions used in the design / calculations. One assumption concerned Motor Operated Valve (MOV) operating voltage ranges, the other assumption concerned assumed margins.
Previously, MOVs were assumed to have an operating voltage range of
+10 to -20% of nameplate. Documentation of the basis for this assumed operating range is no longer available. Therefore the operating ranges for all MOVs have been updated, based on documentation supplied by the valve vendor (Limitorque bulletin LM77) and Limitorque letters to E. R. Bosetti (Detroit Edison),
dated April 24, April 28, and May 22, 1986.
Similarly, in Design Calculation (DC) 919, the setpoint for the degraded grid relay was chosen to be 4% below the degraded grid voltage calculated. Documentation of the basis for this assumed 4%
margin is no longer available. Therefore, this assumed margin has been removed from the calculation.
Using the revised assumptions and as-built plant condition, Detroit Edison reran DC 968 using the higher motor control center voltages necessary to meet Limitorque's 87% limit on the terminal voltage at the valve operator motor. Using these liniting voltages for the 480 volt motor control centers, the necessary ESP bus limits for the 480 volt buses were inserted in DC 835. The limiting voltage for the 4160 volt buses from Design Calculation 835 were then used in Design Calculation 919, Undervoltage Relay Setpoints, to determine the new required degraded relay settings as reflected in the proposed Technical Specification change.
A5-1 Attachment 5 Schematic Diagram - Division I l
l
Attachmsnt Scht.matic Dicgram-Div I Brnst #1 Line Luzo Line 120kV Offsite Source q [.9263 Trans Bus 102 " Bus 101 (120kV) grA Trans 1 CTG-11 120/13 2kV MM yg gg M/A 117/13.2kV Trans Trans
'~
y 3 g gf M Mg MM GSW MCWM :
12.54 /4.16kV CTG 11 LTC + 20-10%
4-18.825kVa Units
[.947]
Bus 64A (BOP)
Non-IE
- IE 50TES: [.950'l _ [.9503
- 2. 4050/480V Connected Ratio 405 0/480V 3950/480V of Transformer
- 3. E.953 Per Unit Voltage for Indicated System
[.9403 [.9533
- Condition Bus 72B (480V) Bus 72C
[.9293 g },g, , , oh M
[.gg Bus 72EA (480P) (480V) MCC MCC (480V) (4801 ) Bus 72EB
.87(460)
O O Trans72EA .83 4(480) Trans72EB 4160/480V ^^ bu 4160/480V r.omi [.95c ]
Bus 11EA (4.16kV) Bus 12EB (4.16kV) ,
1
@ O l EDG EDG Degraded Grid Setpoint-Maximum Bus Loads-Post Start of Two RHR and Two CS Pumps
A6-1 ;
Attachment 6 Schematic Diagram - Division II
. Attachment Schtmatic Diagram-Division 2 Brnst #3 3G W Offsite source Line Bus 302 (345kV)
Line Trans 2A
/
[.984]
Trans -
Bus 301 (345kV) g 2B MTG M Tr*"" 3365
_345/4.16/4.16kV MW. ,
MM
[.936] [.884]
Bus 65G Bus 65D (BOP)
R2cire. Pumps Non IE r soni r soni IE iOTES: Bus 65E (4.16kV) (4.16kV) Bus 65F
- 1. (480V) Nominal Voltage Trans 72EA A A W Trans72F of Bus .
3950/480V 3950/480V 2 3950/480V connected Ratio eg Reg of Transformer /+ 10% + 10%
- 3. Rig g 10%-Auto Adjusting -
(ggoy) [,9393(agoy) 7,9g3]
Regulation
- 4. (.95] Per Unit Voltage Bus 72E Bus 72F For Indicated System Condition f.9781 [.4401 i .c.7 4] gg Bus 72EC(480V) MCC MCC Bus 72ED(480V)
Reg g 10% Reg g 10%
Trans 72EC O 4055/480V O Trans 72ED MOV MOV W A 4055/480V WA r.889] [.8897 Bus 13EC (4.16kV) Bus 14ED (4.16kV)
EDG G
EDG Derraded Grid Setpoint-Maximum Bus Loads-Post Start of Two RHR and Two CS Pumps
A7-1 Attachment 7 Sianificant Hazards Analysis Detroit Edison has reviewed the proposed Technical Specification change against the criteria of 10CPR 50.92(c). Det'roit Edison has concluded that the proposed change involves no significant hazards considerations. The basis for this conclusion is summarized below.
The proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
The proposed revision to Table 3.3.3-2 of Specification
+ 3/4.3.3 would increase the 4.16 kV Emergency Bus Undervoltage (Degraded Grid) (Division 1) instrument setpoint. This would raise the voltage deterioration point at which the Class lE buses would be separated from the offsite power source. The proposed change does not affect any of the parameters of previous accident analyses. The higher voltage setpoint increases the minimum voltage allowed on the Class lE buses to preclude potential damage to their associated equipment.
Although this may increase the probability of a reactor trip resulting from loss of power to the ESP buses, this increase is negligible. The presence of the LTC transformer and the remote potential for offsite power to degrade to voltages which would trip the degraded grid relays assure that the increase in probability of reactor trip is negligible.
This view is supported by the information in Attachment 5.
Attachment 5 shows the voltages on the Division I Class lE buses for the maximum expected loads. From this illustration, it is apparent that the offsite 120kV bus voltage must degrade to 92.6% of nominal (111 kV) to trip the degraded grid relays on Bus 64C. Detroit Edison's records of system voltage suggest that the probability of reaching that lov a voltage on the 120kV bus is very low. In the past ten years, the lowest voltage seen on the 120kV feed is 119kV.
Based on the foregoing, Detroit Edison concludes that the likelihood of reaching the degraded grid relay trip setpoint is very low. Thus, Detroit Edison concludes that the change in setpoints will result in a negligible increase in the probability that additional EDG fast starts and reactor trips will result from implementing the proposed change in Technical Specifications.
A7-2 The longer trip delay time will allow LTC operation to return the bus voltage to the nominal 100% level after a motor starting transient, or a step reduction in the offsite power level. The proposed longer trip delay time allows for LTC response to reduce the probability of an undesirable (i.e, spurious or unnecessary) actuation of the degraded grid relays at their higher setpoint. Because of the reliability of the Detroit Edison electrical network, it is unlikely that the degraded grid relays will be actuated for a degraded grid during the life of Fermi-2. Therefore the increased time delay will not significantly increase the probability or consequences of an accident.
The proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.
The proposed setpoints support the assumptions in the accident analysis that adequate offsite power will be available to operate ECCS equipment or the Class lE buses will be transferred to the EDGs. No new accident possibilities are created by increasing the setpoints or increasing the time delay.
The proposed change does not involve a significant reduction in a margin of safety.
The instrument surveillance frequency and the technical basis for the surveillance requirements are unchanged from the Technical Specifications approved and issued by the NRC with the Fermi-2 license. The ability of offsite and onsite power sources to satisfy the design requirements for the plant is not reduced from the original plant design. Therefore, there is no reduction in the margin of safety.
Based on the foregoing, Detroit Edison concludes that the proposed change to the Technical Specifications involves no significant hazards considerations.
A8-1 Attachnent 8 Environmental Impact To facilitate processing the proposed Technical Specification change as exigent, Detroit Edison has evaluated the environmental impact of the proposed change against the criteria for licensing actions eligible for categorical exclusion from environmental impact statements in 10CFR51.22. The proposed change would revise only the setpoints of the degraded grid undervoltage relays. These components are located in the Auxiliary Building, which is within the Restricted Area. In addition, the proposed change:
- 1) Does not involve a significant hazards consideration Refer to summary of Significant Hazards Consideration presented in Attachment 7.
- 2) Does not change the type of or increase the amount of any effluents that may be released offsite The proposed change affects only the setpoint of electrical undervoltage relaying. This change assures more conservative response of the Fermi-2 plant, affording greater protection of the public health and safety.
- 3) Does not significantly increase the individual or cumulative occupational radiation exposure.
The proposed change affects only the setpoint of electrical undervoltage relaying. This change assures more conservative response of the Fermi-2 plant, affording greater protection of the public health and safety.
Therefore, Detroit Edison concludes that the requested Technical Specification change qualifies for a categorical exclusion from the requirement for an environmental impact statement under 10CPRS1, Subsection 22(c) (9) .
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A9-1 Attachment 9 Impact on Restart In accordance with Technical Specification 3.3.3, the ECCS actuation inctrumentation channels shown in Table 3.3.3-1 shall be operable with their trip setpoints set consistent with the values shown in Table 3.3.3-2. The values listed in Table 3.3.3-2, for item 5.b, Division I, have been determined to be invalid.
Therefore, the intent of Technical Specification operability has not been met for Division I. Special permission was granted by the NRC lettern dated June 13, 1986, for Detroit Edison to consider Division I operable, so that Division II maintenance could proceed. This permission requires Fermi-2 to remain in Operational Conditions 4 or 5.
In accordance with Table 3.3.3-1, item 5.2, the Loss of Power (degraded voltage) function is required to be operable in Operational Condition 1, 2, 3, 4** and 5** (** required when ESF equipment is required to be operable). The plant is presently in Operational Condition 5. In accordance with Technical Specification 3.8.1.2.b the required onsite AC electrical power source is met by the Division I Emergency Diesel Generators (EDGs). The Division II EDGs are currently undergoing their required surveillance inspection, preventive maintenance activities and retesting in accordance with the existing outage schedule.
The intent of Table 3.3.3-1, item 5.2 is no longer met for Division I and the required action would be to declare the associated diesel generators inoperable and take the action required by Technical Specification 3.8.1. The action statement associated with Technical Specification 3.8.1. does not apply at this time because the Division I EDGs are operable, consistent with the provisions of the NRC letters dated June 13, 1986.
Outage work associated with the Division I EDGs is complete and they were placed in standby on June 6, 1986. The present outage schedule calls for restart by July 23, 1986. To enter Operating Conditions 1, 2 or 3, Detroit Edison must have relief from the restriction imposed by Mr. Keppler's June 13, 1986 letter, and have available two onsite AC electrical power sources.
In summary, if the subject Technical Specification change is not approved by July 23, 1986, the restart of Fermi 2 will be delayed on a day-for-day basis. 10CFR 50.91 allows for exigent consideration of changes for which failure to act in a timely way would result in derating on shutdown of a nuclear power plant, or in prevention of either resumpticn of operation or or increase in power input up to the plant's licensed power level. Failure to act on the requested change would result in prevention of resumption of operation and therefore, qualifies for processing as an exigent change.
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