ML20040D844

Revised Tech Spec Pages Per Application for Amend 47 to OL Re RCS Heatup & Cooldown Limits for Cycle 7 Operation

ML20040D844
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Site:	Fort Calhoun
Issue date:	01/27/1982
From:	OMAHA PUBLIC POWER DISTRICT
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2.0 LIMITING CONDITIONS FOR OPERATION 2.1 Reactor Coolant System (Continued) 2.1.2 Heatup and Cooldown Rate (Continued)

KIT is therefore calculated at a maximum gradient and is considered a constant = A for cooldown and zero for heatup.

Mji R is also a constant = B.

t Therefore:

KIR = AP + B P = KTR - B A

KIR is then varied as a function of temperature from Figure G-2110-1 of ASME III and the allowable pressure calculated. Hydrostatic head (48 psi) and instrumentation errors (120F an i 32 psi) are considered when plotting the 4

curves.

3. System Hydrostatic Test - The system hydrostatic test curve is developed in the same manner as in A above with the exception that a safety factor of 1.5 is allowed by ASME III in lieu of 2.

C. Lowest Service Temperature = 500F + 1000F + 120F = 162 0F.

As indicated previously, an RTNDT for all material with the exception of the reactor vessel belt-line was established at 500F. ASME III, Art. NB-2332(b) requires a lowest service temperature of RTNDT + 1000F for piping, pumps and valves. Below this temperature a pressure of 20 percent of

. the system hydrostatic test pressure (.20)(3125) 32 psi = 545 psia cannot be exceeded.

D. Boltup Temperature = 100F + 60 F + 120F = 820F. At pres-sure below 545 psia, a minimum vessel temperature must be maintained to comply with the manufacturer's specifications for tensioning the vessel head. This temperature is based on previous NDTT methods. This temperature corresponds to the measured 100F NDTT of the reactor vessel flange, which is not subject to radiation damage, plus 600F data scatter in NDTT measurements, plus 120F instrument error.

E. Reactor Critical Heatup and Cooldown Figures. During low physics testing, the reactor may be made critical at re-duced temperature and pressure. To provide for heatup and cooldown during testing, Appendix G requires that the RCS temperature be increased an additional 400F beyond heatup and cooldown curves for the non-critical reactor. Also, Appendix G requires that the RCS temperature must be greater than the minimum temperature, 3480F, required for the 2310 psia hydrostatic testing to 110% of the 2100 psia RCS operating pressure, in accordance with Article IWB-5000 of the ASME Boiler and Pressure Vessel Code,Section XI.

Amendment No. 22, 47 2-7 82020 10 820127 pPDR A

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2.0 LIMITING CONDITIONS FOR OPERATION 2.1 Reactor Coolant System (Continued) 2.1.2 Heatup and Cooldown Rate (Continued)

F. Minimum Temperature for 1000F/hr Cooldown Rate = 1530F.

This limit provides protection against low temperature overpressurization during operation of the LPSI pumps. (6)

This temperature corresponds to a pressure of 200 psia on the 1000F/hr curve, which is the LPSI pump dead head and minimum flow pressure. For temperatures of 1530F or less, a cooldown rate of 200F/hr maximum will allow unrestricted operation of the LPSI pumps so that shutdown cooling may be utilized.

References (1) FSAR, Section 4.2.2 (2) ASME Boiler and Pressure Vessel Code,Section III (3) FSAR, Section 4.2.4 (4) FSAR, Section 3.4.6 (5) Omaha Public Power District, Fort Calhoun Station Unit No.

1, Evaluation of Irradiated Capsule W-225, Revision 1 August, 1980.

(6) Technical Specification 2.3(3)

(7) Article IWB-5000, ASME Boiler and Pressure Vessel Code,Section XI.

2-7a

RCS PRESS-TEMP LIMITS C00!.DOWN 6.1 EFPY .

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=2.0 LIMITING CONDITIONS FOR OPERATION 2.3 Emergency Core Cooling System-(Continued)  ;

(3) Protection Against Low Temperature Overpressurization ,

The following limiting conditions shall be applied during scheduled heatups and cooldowns. Disabling of the HPSI-pumps need not be required if the reactor vessel head,'a pressurizer safety valve, or a PORV is removed.

Whenever the reactor coolant system cold leg temperature is

below 3370F, at least one (1) HPSI pump shall be disabled. .l Whenever the reactor coolant. system cold leg temperature is l below 3270F, at least two (2) HPSI pumps shall be disabled. l l Whenever the reactor coolant system cold leg. temperature is '

i below 2930F, all three (3) HPSI pumps shall be disabled. l Whenever the reactor coolant system cold leg temperature is. l l below 153 F, the cooldown rate of Figure 2-1B, Technical 1 ' Specification 2.1.2,~ shall be limited to a maximum rate of 200F/hr.

In the event that no charging pumps are operable, a single -;

HPSI pump may be made operable and utilized for boric acid. l injection to the core.

Basis l The normal procedure for starting the reactor is to first heat the <

reactor coolant to near operating temperature by running the i reactor coolant pumps. The reactor is then made critical by-withdrawing CEA's and diluting boron in the reactor coolant. . With-l this mode of start-up, the energy stored in the reactor coolant

! - during the approach to criticality' is substantially equal to that during power operation and therefore all engineered safety features and auxiliary cooling systems are required to be fully operable.

. During low power. physics tests at low temperatures, there is a negligible amount of stored energy in the reactor coolant; there-i fore, an accident comparable in severity to the design basis accident is not possible and the engineered safeguards systems are not required.

, The SIRW tank contains a minimum of. 283,000 gallons of usable

( . water containing at least 1700 ppm boron.(1)- This is sufficient boron concentration to provide a shutdown margin of 5%, including allowances for uncertainties, with all control rods withdrawn and a new core at a temperature of 60 F. (2) l The limits for the safety injection tank pressure and volume i j

assure the required amount of water injection during an accident-and are based on values used for the accident analyses.- The minimum 116.2 inch level corresponds to a: volume of 825 ft3 and the maximum 128.1 inch level corresponds to a volume of 895.5 ft3 Prior-to the time the reactor is brought critical, the valving of the. safety injection system must be checked for correct alignment and appropriate valved locked.. Since'the system is Amendment No. 17, 39, 43, 47 2-22 4

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2.0 LIMITING CONDITIONS FOR OPERATION 2.3 Emergency Core Cooling System (Continued)

With respect to the core' cooling function, there is functional redundancy over most of'the range of break sizes.(3)(4)

The LOCA analysis confirms adequate core cooling for the break spectrum up to and including the 32 inch double-ended break assuming the safety injection capability which most adversely affects accident consequences and are defined as follows. The entire contents of all four safety injection tanks are assumed to

be available for emergency core cooling, but the contents of one of the tanks is assumed to be lost through the reactor. coolant system. In addition, of the three high-pressure safety injection pumps and the two low-pressure safety injection pumps, for large break analysis it is assumed that two high pressure and one low pressure operate in the small breakwhile only(one analysis 5); and of each alsotype thatis25%

assumed of theirto com-operate bined discharge rate is lost from the reactor coolant system out.

of the break. The transient hot spot fuel clad temperatures for the break sizes considered are shown on FSAR Figures 1-19 (Amend-ment No. 34). .

Inadvertent actuation of three (3) HPSI pumps and three (3) charging pumps, coincident with the opening of one of the two

' PORV's, would result in a peak primary system pressure of 1190 psia. 1190 psia correnponds with a minimum permissible temper-

, ature of 337 F on Figure 2-1B. Thus, at least one HPSI pump is disabled at 3370F.

Inadvertent actuation of two (2) HPSI' pumps and three (3)' charging pumps, coincident with the opening of one of the two PORV's, would result in a peak primary system pressure of 1040 psia. 1040 psia corresponds with a minimum permissible temperature of 327 F on l Figure 2-1B. Thus, at least two HPSI pumps will be disabled at 327 F. l Inadvertent actuation of one (1) HPSI and three (3) charging pumps, coincident with opening of one of the two PORV's, would result in a peak primary system pressure of 685 psia. 685 psia corresponds with a minimum allowable temperature of 2930F on l Figure 2-1B. Thus, all three HPSI pumps will be disabled at 2930F. l The operation of either or both LPSI pumps, with or without three charging pumps, coincident with the opening of one of two PORV's, would result in a peak primary system pressure of 200 psia. This is the LPSI pump dead head and minimum flow pressure. 200 psia corresponds with a minimum allowable temperature of 1530F on the 1000F/hr cooldown rate curve of Figure 2-1B. (6) Since it is necessary that the LPSI pumps be available for shutdown cooling, they cannot be disabled. Thus, whenever the cold leg temperature is less than or equal to 1530F, a maximum cooldown rate of 20 F/hr shall be required.

Amendment No. 39, 47 2-23a

O 2.0 LIMITING CONDITIONS FOR OPERATION 2.3- Emergency Core Cooling System (Continued)

Inadvertent actuation of three (3) charging pumps, coincident with the opening of one of two PORV's, would result in a peak primary system pressure of 160. psia. 160 psia would correspond with a minimum allowable temperature of 121 F on the 100 F/hr cooldown rate curve of . Figure 2-1B. This is less than the minimum 1530F temperature required for-use of the 100 F/hr cooldown rate curve.

Thus, the 200F/hr cooldown rate curve is-controlling and does not limit the operation of the charging pumps.

Removal of the reactor vessel head, one pressurizer safety valve, or one PORV provides sufficient expansion volume to limit any of

' the design basis pressure transients. Thus, no additional relief capacity is required.

Technical Specification 2.2(1) specifies that, when fuel. is in the reactor, at least one flow path shall be provided for boric acid

, injection to the core. Should boric acid injection become neces-sary, and no charging pumps are operable, operation of a single HPSI pump would provide the required flow path.

References (1) FSAR, Section 14.15.1 T

(2) FSAR, Section 6.2.3.1 (3) FSAR, Section 14.15.3 (4) FSAR, Appendix K (5) Omaha Public Power District's Submittal, December 1,1976 -

(6) Technical Specification 2.1.2, Figure 2-1B e

Amendment No. 47 2-23b

DISCUSSION These changes are required to allow for the safe operation of the reactor and associated primary coolant system beyond the 5.2 Equivalent Full Power Years (EFPY) of operation to which the present Technical Specifications are written. The specifications are revised to allow operation through 6.1 EFPY. This will provide operating limits through the end of fuel cycle 7. The EFPY of operation corresponds to a neutron fluence received by the reactor vessel. This fluence causes the nil-ductility transition reference temperature (RTNDT) of the reactor vessel steel to increase. The amount of RTNDT shift is predicted using procedures detailed in Regulatory Guide 1.99. The fluence value for the reactor shift vessel through belt-line 6.1 EFPY of weld materialisused operation 8.4 xforJeterm{ning 10 n/cm . The the RT NDT fluence value for 6.1 EFPY was calqulated using the end-of-life predicted fluence of 4.4 x 1019 n/cmz which was calculated and approved by the Commission for cycle 6 operation using the Fort Calhoun Station first surveillance capsule test data, as reported in the Combustion Engineer-ing document " Evaluation of Irradiated Capsule W-225", Revision 0, dated May 1979. It should be noted that the CE report, " Evaluation of Ir-calculational techniques determined the EOL fluence to be 4.2 x 10g)' radiated Capsu n/cm2 Accordingly, the E0L value and 6.1 EFPY fluence values used in the proposed calculated Technical Specifications are considgred conservative. The RTNDT total shift for 8.4 x 1018 n/cm is 2380F for the belt-line weld material. The heatup and cooldown rate pressure-temperature limit curves were then adjusted according to 10 CFR 50, Appendices G and H, to c.nsure that adequate fracture toughness is maintained through all conditions of normal operation, including anticipated operational transients and system hydrostatic tests. The beginning-of-life RTNDT value for weld materials used for developing the heatup ano cooldown limit curves was 00F in accc-dance with Branch Technical Position MTEB 5-2.

The disabling of HPSI pumps in order to ensure protection of the RCS against low temperature overpressurization is dependent upon the permissible 1000F/hr cooldown rate which is determined from the shift in RTNDT and plotted on Figure 2-18. Thus, Technical Specification 2.3(3) is modified to maintain adequate overpressurization protection. In addition, it has become apparent that the LPSI pump shutoff head will not allow operation on the 1000F/hr cooldown rate curve of Figure 2-1B at temperature at or below 1530F. It becomes necessary to limit oper-ation at that temperature and below to a cooldown rate of 200F/hr.

The present Technical Specifications, valid through 5.2 EFPY, will provide operating limits for a period of 47 days of full power operation (71,662 MW-HR) after initial criticality of fuel cycle 7. Therefore, Commission approval of the proposed Technical Specifications by no later than February 8,1982 is requested.

ATTACHMENT B

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