ML20106D825

From kanterella
Jump to navigation Jump to search
Proposed Tech Specs 2.14,Table 2-1,Item 6.b Re ESF Sys Initiation Instrument Setting Limits
ML20106D825
Person / Time
Site: Fort Calhoun Omaha Public Power District icon.png
Issue date: 10/07/1992
From:
OMAHA PUBLIC POWER DISTRICT
To:
Shared Package
ML20106D818 List:
References
NUDOCS 9210140398
Download: ML20106D825 (8)


Text

. ,

U.S. Nuclear Regulatory Commission LIC-92-099A ATTACHMENT A

?!A 2288 M Ha88?os P PDR

Q TABLE 2-1 ENGINEERED SAFETY FEATURES SYSTE%f INITIATION INSTRU3fEST SETTING LI5flTS Functional Unit Channel Se* tine Lim _it

1. High Containment Pressure a. Safety Injection '15 psig
b. Containment Spray *
c. Cortainment Isolation
d. Containment Air Cooler DBA Mode
e. Steam Geaerator Isolation
2. Pressurizer low / Low Pressure a. Safety Injection 21600 psia *
b. Containment Spray *
c. Containment Isolation
d. Containment Air Ccoler DBA Mode
3. Containment liigh Radiation Containment Ventilation Isohtion In accordance with the Offsite Dw Celwhtion Manual
4. Low Steam Generator Pressure a. Steam Line Isolation 1500 psia a
b. Auxiliary Feedwater Actuation 1466.7 psia
5. SIRW low level Switches Recirculation Actuation 16 inches + 0, -2 in. above tank bottom
6. 4.16 KV Emergency Bus Low a. Loss of Voltage (2995.2 + IM, -20.8) volts Voltage 15.9* seconds } TRIP
b. Degraded Voltage 1 -382L&2 4g29]4 volts i) Bus 1 A3 Side (4.8 i .5) seconds } TRIP 2-64 Amendmeet No. 44,65,86,408

,w TABLE 2-1 (Continual) l l ENGINEERED SAFETY FEATURES SYSTEM f"' ATION INSTRU5fENT SETTING LIMITS Channti Setting Limit Eunctional linit

6. (Continued) b. (Continued) 1 W34481978.6 volts ii) Bus I A4 Side (4.81 5) seconds } TRIP
7. lew Steam Generator Water Auxiliary Feedwater Actuation 128.2% of wide range tap span l level i
8. liigh Steam Generator Delta Auxiliary Em! water Actuation i 119.7 psid Pressure l

l L

l (1) May be bypassed below 1700 psia and is automatically reinztated above 1700 psia.

1 (2) May be bypassed below 550 psia and is ratometically reinstated above 550 psia.

(3) Simultaneous high containment pres.;ure and pressurizer low / low pressure.

(4) Applicable for bus voltage i 2995.2 - 20.8 volts only. (For voltage 1(2995.2 - 20.8) volts, time delay shall be > 5.9 sceonds.)

l 2-64a Ammammt No. 44,65,36

6 TABLE 2-1 ENGI;TrffRED SAFETY FEA'I1URES SYSTEM INITIATION INSTRUMENT SETTING LIMITS Eunctional Upjl Channel Settine Limit

1. High Containment Pressure a. Safety Injection 15 psig
b. Containment Spray * ,
c. Containnnt Isolation
d. Containment Air Cooler -

DBA Mode

e. Steam Generator Isolation
2. Pressurizer LowLru Pressure a. Safety injection 21600 psia *
b. Containment Spray *
c. Containment Isolation
d. Containtnent Ait Cooler DBA Mode
3. Containment fligh Radiation Containment Ventilation Isolation In accordance with the Offsite Dose Calculation Manuci
4. Low Steam Generator Pressure a. Steam Line Isolation A 500 peia m
b. Auxiliary Feedwater Actuation 1466.7 psia '
5. SIRW Iew Level Switches Recirculation Actuation 16 inches 4-0, -2 in. a'oove tank bottom
6. 4.16 KV Emergency Bus Low a. las of Voltage (2995.2 + iO4, -20.8) volts Voltage i 5.9'* seconds ) TRIP
b. Degraded Voltage 14o29.4 volts l i) Bus I A3 Side (4.8 f. 5) seconds } TRIP 2-64 Amendment No. ^1,G,46.408

'~

TABLE 2-1 (Continued)

ENGINEERED SAFETY FEATURES SYSTEM INmATION IFRRUMENT SETTING LIMITS -

Functional Ifnit Channel Settine Limit

6. (Continued) b. (Continued)' 13978.6 volts {

ii) Bus I A4 Side (4.8 f_ .5) seconds } TRIP 7.1.ow Steam Generator Water Auxiliary Feedwater Actuation 128.4% of wide range tap span Level

8. liigh Steam Generator Delta Auxiliary Feedwater /.ctuation i 119.7 psid Pressure (1) May be bypassed below 1700 psia and is automatically reinstated above 1700 psia.

(2) May be bypassed below 550 psia and is automatically reinstated above 553 psia.

(3) Simultaneous high contairanent pressure and pressurizer low / low pressure.

(4) Apr8icable for bus voltage i 2995.2 - 20.8 volts only. . (For veltzge 1(2995.2 - 20.8) volts, time delsy shall be > 5.9 sawmis.)

2-64a AW-t No. 44,65,86 a

U U.S. Nuclear Regulatory Comission LIC-92-099A.

ATTACHMENT B

01}CUS$10N. JUSTIFICATION AND H0 SlaNIFICANT HAZARDS CONSIDERATIONS DISCUSSION AND JUSTIFICATION Omaha Public Power District (0 PPD) proposes to change Fort Calhoun Station Unit No.1 Technical Specification 2.14, Table 2-1, Item No. 6.b. that specifies the setpoint limit for degraded voltage protection.

To ensure that adequate vo. age from the 161 KV offsite power supply to 4.16 KV safeguards buses lA3 and 'A4 exists during an accident, the electrical distribution system has been equipped with a degraded voltage protection system referred to as Offsite Power Low Signal (OPLS). The OPLS provides protection to safeguards equipment when a degraded voltage condition is detected on 4.16 KV buses a When IA3 or lA4, concurrent degraded with a Safety voltage condition exists injection Actuation concurrent Signalthe with a SIAS, (SIAS)s.

0?m isolates 4.16 KV buses lA3 and 1A4 from the 161 KV cffsite power supply- and initiates automatic actions to load the safeguards equipment onto the emergency diesel generators. The GPLS setpoints were originally designed to ensure that the voltage supplied to the 4160 V and 480 V loads does not drop below 90% of the nameplate voltage rating during an accident. The motor manufacturer recommends that terminal voltage be maintained at a minimum of 90% of motor nameplate rating to protect the motors from overheating due to excersive current.

An engineering analysis revealed that during an accident in which safeguards equipment would be required to operate, the voltage supplied to some 480 V safeguards loads could degrade to approximately 87.5% of rated voltage without attuating OPLS. Therefore, in February 1991, the- 0PLS was determined to be outside its design basis. This situation was reported to the NRC in Licensee Event Report 50-285/91-04 dated March 21, 1991, which was subsequent'.y revised on June 21, 1991. Interim corrective actions included placing administrative restrictions on equipment rotation and bus loading configurations. Also, the OPLS setpoints were increased to provide protection consistent with the allowable configurations. In order to remove the operational restrictions of the interim corrective actions, a modification was 1mplemented during the 1992 refueling outage.

This mo61fication alters the existing logic circuitry such that upon receipt of a SIAS, the large 4160 volt motors and equipment (i.e., feedwater, beater drain and condensate pumps) ne required to mitigate the consequences of an accident are automatically load shed. Controls have been modified so that during normal operations, plant personnel have additional flexibility in loading equipment onto 4.16 KV buses lA3 and 1A4. The modification raises the OPLS setpoints so that it actuates (assuming a concurrent SIAS) at a higher level of decreasing voltage or. 4.16 KV safeguards buses IA3 and 1A4 based on Engineering Analysis EA-FC 057. As a result, the current OPLS setpoints listed in Technical Specification 2.14, Table 2-1 Item No. 6.b. must be increased.

Admin;strative Chanaes Amendment number 108 is being added to the bottom of page 2-64 as the current revision to this page. Presently this amendment number is not legible on pag?

2-64.

1

l BASIS FOR NO Sl@ilFICANT HAZARDS CONSl0 ERAT 10H The proposed changes do not involve significant hazards considerations because operation of Fort Calhoun Station Unit No.1 in accordar.ce with these changes would not:

(1) Involve a significant increase ir. the probability or consequence:; of an accident previously evaluated.

OPLS actuates only when a degraded voltage condition is detected on 4.16 KV safeguards buses lA3 or lA4 concurrent with a SIAS. The proposed change to Technical Specification 2.14, Table 2-1, item No. 6.b. (0PLS setpoints) prcvides additional assurance that the safety related loads that are sequenced on in this situation will have adequate voltage to accelerate to rated speed. In addition, the proposed increase in OPLS setpoints will insure that voltage is maintained at a minimum of 90% of "

nameplate rating to protect the 480 V motors from overheating due to excessive current. The proposed change to Technical Specification 2.14,

  • Table 2-1, Item No. 6.b. restores the level of safety intended by the design basis of OPLS. Therefore, neither the probability nor consequences of an accident previously evaluated are increased.

(2) Create the possibility of new or different kind of accident from any previously analvzed.

The proposed change will cause OPLS to actuate at a higher level of decreasing voltage (concurrent with a SIAS) on 4.16 KV buses lA3 and 1A4.

For reasons stated in the response to Item 1 above, this proposed change ensures the level of safety intended by the design basis of OPLS and provides additional protection to safeguards loads, it does not create the possibility of a new or different kind of accident.

(3) Involve a significant reduction in a margin of safety.

The proposed increase in Technical Specification 2.14, Table 2-1, Item No.

6.b. (OPLS setpoints) revises a nonconservative limit that currently exists in Technical Specification 2.14, Tabla 2-1, item No. 6.b. The a proposed change provides assurance that safety related loads will have adequate voltage to accelerate to rated speed and that the voltage on 4.16 KV buses lA3 and 1A4 does not drop below 90% of the nameplate voltage rating during an accident. Therefore, the proposed change to Technical Specification 2.14, Table 2-1, Item No. 6.b. (OPLS setpoints) increasns the margin of safety as compared with the current Technical Specification 2.14, Table 2-1, Item No. 6.b. setpoints.

Thereforc, based on the above considerations, it is OPPD's position that this .

proposed amendment does not i n .>ol ve a significant hazards consideration as defined by 10 CFR 50.92 and the proposed changes will not result in a condition which significantly alters the impact of the Station on the environment. Thus, the proposed change meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(e)(9) and pursuant to 10 CFR 51.22(b) no environmental assessment need be preparad.

2 E _ __ _ _. _ __ ____..- _____.._------_ _ ______ _ _ .