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Enclosure 2 - Volume 10 - St. Lucie Plant, Units 1 and 2, Improved Technical Specifications Conversion ITS Section 3.5 Emergency Core Cooling Systems (Eccs), Revision 0
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ENCLOSURE 2 VOLUME 10 ST. LUCIE PLANT UNIT 1 AND UNIT 2 IMPROVED TECHNICAL SPECIFICATIONS CONVERSION ITS SECTION 3.5 EMERGENCY CORE COOLING SYSTEMS (ECCS)

Revision 0

LIST OF ATTACHMENTS

1. 3.5.1, Safety Injection Tanks (SITs)

2. 3.5.2, ECCS - Operating

3. 3.5.3, ECCS - Shutdown

4. 3.5.4, Refueling Water Tank (RWT)

5. 3.5.5, Trisodium Phosphate (TSP) - Unit 2 only

ATTACHMENT 1 3.5.1, Safety Injection Tanks (SITs)

Current Technical Specifications (CTS) Markup and Discussion of Changes (DOCs)

ITS ITS 3.5.1 A01 3/4.5 EMERGENCY CORE COOLING SYSTEMS (ECCS)

SAFETY INJECTION TANKS (SITs)

LIMITING CONDITION FOR OPERATION Four s LCO 3.5.1 3.5.1 Each reactor coolant system safety injection tank shall be OPERABLE with:

Verify each SIT is fully SR 3.5.1.1 a. The isolation valve open, Verify borated water volume in each SIT is SR 3.5.1.2 b. Between 1090 and 1170 cubic feet of borated water, Verify in each SIT is 2200 ppm M01 SR 3.5.1.4 c. A minimum boron concentration of 1900 ppm, and in each SIT is SR 3.5.1.3 d. A nitrogen cover-pressure of between 230 and 280 psig.

Applicability APPLICABILITY: MODES 1, 2 and 3 with pressurizer pressure 1750 psia ACTION:

level one SIT inoperable Condition A a. With one SIT inoperable due to boron concentration not within limits, or due to an inability to verify the required water volume or nitrogen cover-pressure, restore the Required Action A.1 inoperable SIT to OPERABLE status with 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months ; otherwise, be in at least HOT Required Action MODE 3 STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in HOT SHUTDOWN within the following C .1, C.2 12 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months . Reduce pressurizer pressure to < 1750 psia A02 for Condition B b. With one SIT inoperable due to reasons other than those stated in ACTION-a, Required Action B.1 restore the inoperable SIT to OPERABLE status within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months ; otherwise, be in Required Action MODE 3 at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in HOT SHUTDOWN within C .1, C.2 the following 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months . A02 Reduce pressurizer pressure to < 1750 psia 12 Add proposed Action D A03 SURVEILLANCE REQUIREMENTS 4.5.1 Each safety injection tank shall be demonstrated OPERABLE:

SR 3.5.1.1, SR 3.5.1.2, a. In accordance with the Surveillance Frequency Control Program by:

SR 3.5.1.3 in each SIT is SR 3.5.1.2 1. Verifying that the borated water volume and nitrogen cover-pressure in the SR 3.5.1.3 tanks are within their limits, and SR 3.5.1.1 2. Verifying that each safety injection tank isolation valve is open.

ST. LUCIE - UNIT 1 3/4 5-1 Amendment No. 157, 213, 223, 247

ITS ITS 3.5.1 A01 EMERGENCY CORE COOLING SYSTEMS SURVEILLANCE REQUIREMENTS (continued) NOTE Only required to be A04 performed for affected SIT.

SR 3.5.1.4 b. In accordance with the Surveillance Frequency Control Program and once within 6 that is not the result of hours after each solution volume increase of > 1% of tank volume by verifying the addition from the RWT.

boron concentration of the safety injection tank solution. This latter surveillance is in each SIT is 1900 ppm and 2200 ppm.

not required when the volume increase makeup source is the RWT and the RWT has not been diluted since verifying that the RWT boron concentration is equal to LA01 or greater than the safety injection tank boron concentration limit.

removed from each SIT SR 3.5.1.5

c. In accordance with the Surveillance Frequency Control Program when the RCS A05 pressure is above 1750 psia, by verifying that power to the isolation valve operator is removed by maintaining the breaker open under administrative control. LA02

d. In accordance with the Surveillance Frequency Control Program by verifying that each safety injection tank isolation valve opens automatically under each of the LA04 following conditions:

1. When the RCS pressure exceeds 350 psia, and

2. Upon receipt of a safety injection test signal.

ST. LUCIE - UNIT 1 3/4 5-2 Amendment No. 133, 157, 223

ITS ITS 3.5.1 A01 3/4.5 EMERGENCY CORE COOLING SYSTEMS (ECCS) 3/4.5.1 SAFETY INJECTION TANKS (SITs)

LIMITING CONDITION FOR OPERATION Four s LCO 3.5.1 3.5.1 Each Reactor Coolant System safety injection tank shall be OPERABLE with:

Verify each SIT is fully SR 3.5.1.1 a. The isolation valve open, Verify in each SIT is SR 3.5.1.2 b. A contained borated water volume of between 1420 and 1556 cubic feet, Verify in each SIT is ppm SR 3.5.1.4 c. A boron concentration of between 1900 and 2200 ppm of boron, and in each SIT is SR 3.5.1.3 d. A nitrogen cover-pressure of between 500 and 650 psig.

NOTE When in MODE 3 with pressurizer pressure is less than 1750 psia, at least three safety injection tanks shall be OPERABLE, each with a minimum pressure of 235 psig and a maximum pressure of 650 psig and a contained water volume of LA03 between 1250 and 1556 cubic feet with a boron concentration of between 1900 and 2200 ppm of boron. With all four safety injection tanks OPERABLE, each tank shall have a minimum pressure of 235 psig and a maximum pressure of 650 psig and a contained water volume of between 833 and 1556 cubic feet with a boron concentration of between 1900 and 2200 ppm of boron.

Applicability APPLICABILITY: MODES 1, 2 and 3 with pressurizer pressure 1750 psia.

ACTION:

level one SIT inoperable Condition A a. With one SIT inoperable due to boron concentration not within limits, or due to an inability to verify the required water volume or nitrogen cover-pressure, restore the Required Action A.1 inoperable SIT to OPERABLE status with 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months ; otherwise, be in at least HOT Required Action MODE 3 STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in HOT SHUTDOWN within the following C .1, C.2 12 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months . Reduce pressurizer pressure to < 1750 psia A02 for Condition B b. With one SIT inoperable due to reasons other than those stated in ACTION-a, Required Action B.1 restore the inoperable SIT to OPERABLE status within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months ; otherwise, be in Required Action MODE 3 at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in HOT SHUTDOWN within C .1, C.2 the following 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months . Reduce pressurizer pressure to < 1750 psia A02 12 Add proposed Action D A03 SURVEILLANCE REQUIREMENTS 4.5.1.1 Each safety injection tank shall be demonstrated OPERABLE:

SR 3.5.1.1, SR 3.5.1.2, a. In accordance with the Surveillance Frequency Control Program by:

SR 3.5.1.3 in each SIT is SR 3.5.1.2 1. Verifying that the borated water volume and nitrogen cover-pressure in the SR 3.5.1.3 tanks are within their limits, and SR 3.5.1.1 2. Verifying that each safety injection tank isolation valve is open.

ST. LUCIE - UNIT 2 3/4 5-1 Amendment No. 40, 58, 96, 100, 163, 173, 199

ITS ITS 3.5.1 A01 MERGENCY CORE COOLING SYSTEMS SURVEILLANCE REQUIREMENTS (Continued) NOTE Only required to be A03 performed for affected SIT.

SR 3.5.1.4 b. In accordance with the Surveillance Frequency Control Program and once within that is not the result of 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months after each solution volume increase of greater than or equal to 1% of tank addition from the RWT.

volume by verifying the boron concentration of the safety injection tank solution.

in each SIT is 1900 ppm and 2200 ppm.

This latter surveillance is not required when the volume increase makeup source is the RWT and the RWT has not been diluted since verifying that the RWT boron LA01 concentration is equal to or greater than the safety injection tank boron concentration limit.

removed from each SIT SR 3.5.1.5 c. In accordance with the Surveillance Frequency Control Program when the RCS LA05 pressure is above 700 psia, by verifying that power to the isolation valve operator is disconnected by maintaining the breaker open by administrative controls. LA02

d. In accordance with the Surveillance Frequency Control Program by verifying that each safety injection tank isolation valve opens automatically under each of the LA04 following conditions:

1. When an actual or simulated RCS pressure signal exceeds 515 psia, and

2. Upon receipt of a safety injection test signal.

ST. LUCIE - UNIT 2 3/4 5-2 Amendment No. 72, 96, 173

DISCUSSION OF CHANGES ITS 3.5.1, SAFETY INJECTION TANKS (SITs)

ADMINISTRATIVE CHANGES A01 In the conversion of the St. Lucie Plant (PSL) Unit 1 and Unit 2, Current Technical Specifications (CTS) to the plant specific Improved Technical Specifications (ITS), certain changes (wording preferences, editorial changes, reformatting, revised numbering, etc.) are made to obtain consistency with NUREG-1432, Rev. 5.0, "Standard Technical Specifications-Combustion Engineering Plants" (ISTS).

These changes are designated as administrative changes and are acceptable because they do not result in technical changes to the CTS.

A02 CTS 3.5.1 Actions a. and b. require in part, otherwise, be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in HOT SHUTDOWN within the following 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months when a SIT cannot be restored to OPERABLE status within the required time. ITS 3.5.1 Required Action C.2 requires, when the Required Actions and associated Completion Times are not met, reducing pressurizer pressure to

< 1750 psia. This changes the end state in CTS 3.5.1 Actions a. and b. from MODE 4 to MODE 3 with pressurizer pressure < 1750 psia.

The purpose of CTS 3.5.1 Action a. and b. is to place the plant in a condition in which the equipment is no longer required. CTS 3.5.1 Action a. and b. provide appropriate actions to take for an inoperable SIT when the unit is in MODE 1, 2, or 3 with pressurizer pressure is 1750 psia. The SIT is not required to be OPERABLE when pressurizer pressure is < 1750 psia. Below 1750 psia, the rate of RCS blowdown is such that the ECCS pumps can provide adequate injection to ensure that peak clad temperature remains below 10 CFR 50.46 limit of 2200°F. Therefore, in accordance with CTS 3.0.2 (ITS LCO 3.0.2), when pressurizer pressure is < 1750 psia, the requirements to be in MODE 4 in CTS 3.5.1 Action a. and b. are no longer required to be completed. The SITs, with pressurizer pressure below 1750 psia, are no longer required to be OPERABLE.

These changes are designated as administrative changes and are acceptable because they maintain the current requirement to place the unit in a condition in which the SITs are no longer required consistent with the requirements of CTS 3.0.2 (ITS LCO 3.0.2) and, therefore, do not result in a technical change to the CTS.

A03 CTS 3.5.1 does not contain a specific ACTION for two or more SITs inoperable.

With two or more SITs inoperable, CTS 3.0.3 would be entered. ITS 3.5.1 ACTION D directs entry into LCO 3.0.3 when two or more SITs are inoperable.

This changes the CTS by specifically stating to enter LCO 3.0.3 in this System Specification.

This change is acceptable because the action taken with two or more SITs inoperable is unchanged. Adding this ACTION is consistent with the ITS convention of directing entry into LCO 3.0.3 when multiple ACTIONS are presented in the ITS, and entry into these multiple ACTIONS could result in a loss of safety function. This change is designated as administrative because it does not result in a technical change to the CTS.

St. Lucie Unit 1 and Unit 2 Page 1 of 7

DISCUSSION OF CHANGES ITS 3.5.1, SAFETY INJECTION TANKS (SITs)

A04 Unit 1 CTS 4.5.1.b, and Unit 2 CTS 4.5.1.1.b state, in part, that verification of the boron concentration of the SIT solution is required once within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months after each solution volume increase of 1% of tank volume; however, this surveillance is not required when the volume increase makeup source is the RWT and the RWT has not been diluted since verifying that the RWT boron concentration is equal to or greater than the SIT boron concentration limit.

The purpose of the Unit 1 CTS 4.5.1.b, and Unit 2 CTS 4.5.1.1.b Surveillance Frequency is to designate the Frequency, as well as certain requirements or special conditions. ITS SR 3.5.1.4 adds a Note to the Surveillance Frequency that states Only required to be performed for affected SIT. The CTS Surveillance Frequency is implicit that the Surveillance be performed for only the affected SIT, that being the SIT subject to the solution volume increase. CTS does not contain this Note. This changes the CTS by adding the ITS SR 3.5.1.4 Note to clarify that the Surveillance is only required to be performed for the affected SIT. This change is acceptable because ITS SR 3.5.1.4 Note clarifies that the Surveillance is only required to be performed for the affected SIT. This change is designated as administrative because it does not result in technical changes to CTS.

A05 Unit 1 only: Unit 1 CTS 4.5.1.c requires verification that power be removed from each SIT isolation valve operator when RCS pressure is above 1750 psia. ITS SR 3.5.1.5 requires verification that power be removed from each SIT isolation valve operator when pressurizer pressure is greater than or equal to a specific pressure. This changes the CTS by deleting the specific pressure at which power be removed from the SIT isolation valve operators.

The purpose of the CTS requirement is to ensure power is removed from each SIT isolation valve operator when RCS pressure is above a specific value to further ensure that an active failure could not result in the undetected closure of an SIT motor operated isolation valve. This pressure value is typically above the pressure the SITs are required to be OPERABLE. For instance, the ISTS 3.5.1 Applicability is, in part, with pressurizer pressure 700 psia and ISTS SR 3.5.1.5 requires power to be removed from the isolation valve operator 2000 psia. Per the requirements of CTS 4.0.1 (ITS SR 3.0.1) and CTS 4.0.4 (ITS SR 3.0.4), SRs must be met prior to entry into the Applicability, which in the case of CTS 3.5.1 (ITS LCO 3.5.1) is MODES 1 and 2, and MODE 3 with pressurizer pressure 1750 psia. Conversely, as stated in the ITS Bases of SR 3.0.1, Surveillances do not have to be performed when the unit is in a MODE or other specified condition for which the requirements of the associated LCO are not applicable.

Therefore, it is unnecessary to specifically require power to the valve operator be removed "when in MODE 3 with pressure 1750 psia" and this additional wording has been removed from Unit 1 ITS SR 3.5.1.5. As such, this additional wording has been removed from Unit 2 ITS SR 3.5.1.5.

This change is acceptable because ITS SR 3.5.1.5 requires essentially the same verification by requiring that power be removed from each SIT isolation valve operator when the SITs are required to be OPERABLE (i.e., when pressurizer pressure is greater than or equal to 1750 psia for Unit 1. This change is designated as administrative because it does not result in technical changes to CTS because the Surveillance requirement will continue to require power to the St. Lucie Unit 1 and Unit 2 Page 2 of 7

DISCUSSION OF CHANGES ITS 3.5.1, SAFETY INJECTION TANKS (SITs)

SIT isolation valve operator to be removed when the SITs are required to be OPERABLE (i.e., in MODES 1 and 2, and MODE 3 with pressurizer pressure 1750 psia).

MORE RESTRICTIVE CHANGES M01 Unit 1 only: CTS 3.5.1.c requires a minimum SIT boron concentration of 1900 ppm but does not require a maximum boron concentration. ITS SR 3.5.1.4 requires verification that SIT boron concentration is within both a minimum and maximum limit. Similarly, Unit 2 CTS 3.5.1.c requires boron concentration within a minimum 1900 ppm and a maximum 2200 ppm. This changes the Unit 1 CTS by adding a SIT boron concentration maximum limit of 2200 ppm.

The purpose of CTS 3.5.1.c is to provide a SIT minimum boron concentration limit to ensure that, following a LOCA with a minimum level in the SIT, the reactor will remain subcritical in the cold condition following mixing of the SIT and RCS water volumes. The SIT maximum boron concentration limit is based on boron precipitation in the core following a LOCA which could result in reduced heat removal capability between the fuel cladding and the reactor coolant. This change is acceptable, because the maximum boron concentration limit provides assurance that the SIT is capable of performing its function when required. This change is designated as more restrictive because it adds a SIT maximum boron concentration limit to the CTS.

RELOCATED SPECIFICATIONS None REMOVED DETAIL CHANGES LA01 (Type 3 - Removing Procedural Details for Meeting TS Requirements or Reporting Requirements) PSL Unit 1 CTS 4.5.1.b, and PSL Unit 2 CTS 4.5.1.1.b state that verification of boron concentration of the SIT solution is required once within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months after each solution volume increase of 1% of tank volume, and that the Surveillance is not required when the volume increase makeup source is the RWT and the RWT has not been diluted since verifying that the RWT boron concentration is equal to or greater than the SIT boron concentration limit. ITS SR 3.5.1.4 states that verification of boron concentration of each SIT is required once within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months after each solution volume increase of 1% of tank volume that is not the result of addition from the refueling water tank. ITS does not include a Surveillance Frequency requirement that retains the statement that the RWT has not been diluted since verifying that the RWT boron concentration is equal to or greater than the SIT boron concentration limit. This changes the CTS by relocation of the CTS requirement to the ITS Bases. The ITS 3.5.1.4 Bases will include that it is not necessary to verify boron concentration if the added water is from the RWT, because the boron concentration of the water contained in the RWT is within the SIT boron concentration requirements.

St. Lucie Unit 1 and Unit 2 Page 3 of 7

DISCUSSION OF CHANGES ITS 3.5.1, SAFETY INJECTION TANKS (SITs)

The removal of these details for performing surveillance requirements from the Technical Specifications is acceptable because this type of information is not necessary to be included in the Technical Specifications to provide adequate protection of public health and safety. ITS SR3.5.1.4 retains the CTS PSL Unit 1 CTS 4.5.1.b, and PSL Unit 2 CTS 4.5.1.1.b, requirement by stating that verification of boron concentration of the SIT solution is required once within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months after each solution volume increase of 1% of tank volume that is not the result of addition from the refueling water tank. Also, this change is acceptable because these types of procedural details will be adequately controlled in the ITS Bases. Changes to the Bases are controlled by the Technical Specification Bases Control Program in Chapter 5. This program provides for the evaluation of changes to ensure the Bases are properly controlled. This change is designated as a less restrictive removal of detail change because procedural details for meeting Technical Specification requirements are being removed from the Technical Specifications.

LA02 (Type 3 - Removing Procedural Details for Meeting TS Requirements or Reporting Requirements) PSL Unit 1 CTS 4.5.1.c, and PSL Unit 2 CTS 4.5.1.1.c require verifying that power to the (SIT) isolation valve operator is removed /

disconnected by maintaining the breaker open under administrative control. ITS SR 3.5.1.5 states verify power is removed from each SIT isolation valve operator. ITS does not include the detailed requirement that the breaker to the isolation valve operator be maintained open under administrative control. This changes the CTS by relocation of the administrative control details to the ITS Bases. The ITS 3.5.1.5 Bases will include that removal of power to the SIT isolation valve operators is conducted under administrative control.

The removal of these details for performing surveillance requirements from the Technical Specifications is acceptable because this type of information is not necessary to be included in the Technical Specifications to provide adequate protection of public health and safety. ITS SR 3.5.1.5 retains the requirement to ensure power is removed from the SIT isolation valve operator. ITS SR 3.5.1.5 states verify power is removed from each SIT isolation valve operator. This change is acceptable because these types of procedural details will continue to be adequately controlled in the ITS Bases. Changes to the Bases are controlled by the Technical Specification Bases Control Program in Chapter 5. This program provides for the evaluation of changes to ensure the Bases are properly controlled. This change is designated as a less restrictive removal of detail change because procedural details for meeting Technical Specification requirements are being removed from the Technical Specifications.

LA03 Unit 2 only: (Type 4 - Removal of LCO, SR, or other TS requirement to the TRM, UFSAR, ODCM, QAP, CLRT Program, IST Program, ISI Program, or Surveillance Frequency Control Program) CTS 3.5.1 LCO Note states When in MODE 3 with pressurizer pressure less than 1750 psia, at least three safety injection tanks shall be OPERABLE, each with a minimum pressure of 235 psig and a maximum pressure of 650 psig and a contained water volume of between 1250 and 1556 cubic feet with a boron concentration of between 1900 and 2200 ppm of boron. With all four safety injection tanks OPERABLE, each tank shall have a minimum pressure of 235 psig and a maximum pressure of 650 psig and a contained water volume of between 833 and 1556 cubic feet with a boron St. Lucie Unit 1 and Unit 2 Page 4 of 7

DISCUSSION OF CHANGES ITS 3.5.1, SAFETY INJECTION TANKS (SITs) concentration of between 1900 and 2200 ppm of boron. ITS 3.5.1 does not include this requirement. PSL Unit 2 CTS 3.5.1 Applicability is MODES 1, 2, and 3 with pressurizer pressure 1750 psia. The SIT is not required to be OPERABLE when pressurizer pressure is < 1750 psia. Therefore, in accordance with CTS 3.0.2 (ITS LCO 3.0.2), when pressurizer pressure is < 1750 psia, the requirements in the Note are no longer required. Similarly, DOC A02 changes the end state in CTS 3.5.1 Actions a. and b. from MODE 4 to MODE 3 with pressurizer pressure < 1750 psia. This changes the CTS by relocating the requirements in the Note to the Technical Requirements Manual.

The removal of SIT requirements when in MODE 3 with pressurizer pressure

< 1750 psia is acceptable because this type of information is not necessary to be included in the Technical Specifications in order to provide adequate protection of public health and safety. The ITS retains the requirements for SITs to be OPERABLE when in MODES 1, 2, and 3 with pressurizer pressure 1750 psia.

When pressurizer pressure is below 1750 psia the ECCS pumps can provide adequate injection to ensure that peak clad temperature remains below the 10 CFR 50.46 limit of 2200°F. Therefore, the SITs are not required to be OPERABLE and the SIT motor operated isolation valves may be closed to isolate the SITs from the RCS during plant shutdown or startup. Also, this change is acceptable because these types of procedural details will continue to be controlled in the TRM. The TRM is incorporated by reference into the UFSAR and any changes to the TRM are made under 10 CFR 50.59, which ensures changes are properly evaluated. This change is designated as a less restrictive removal of detail change because these SIT requirements are not required by the CTS 3.5.1 and ITS 3.5.1 Applicability, that being MODES 1 and 2, and MODE 3 with pressurizer pressure 1750 psia.

LA04 (Type 4 - Removal of LCO, SR, or other TS requirement to the TRM, UFSAR, ODCM, QAP, CLRT Program, IST Program, ISI Program, or Surveillance Frequency Control Program) PSL Unit 1 CTS 4.5.1.d states In accordance with the Surveillance Frequency Control Program by verifying that each safety injection tank isolation valve opens automatically under each of the following conditions: When the RCS pressure exceeds 350 psia, and Upon receipt of a safety injection test signal. PSL Unit 2 CTS 4.5.1.1.d states In accordance with the Surveillance Frequency Control Program by verifying that each safety injection tank isolation valve opens automatically under each of the following conditions: When an actual or simulated RCS pressure signal exceeds 515 psia, and Upon receipt of a safety injection test signal.

ITS 3.5.1 does not include this requirement. ITS SR 3.5.1.1 requires verification that each SIT isolation valve is fully open when in MODES 1 and 2, and MODE 3 with pressurizer pressure 1750 psia. Additionally, ITS SR 3.5.1.5 requires verification that power is removed from each SIT isolation valve operator when pressurizer pressure is 1750 psia. ITS SR 3.5.1.1 and SR 3.5.1.5 provide assurance the each SIT isolation valve is open and remains open (power removed from its valve operator) when in MODES 1 and 2, and MODE 3 with pressurizer pressure 1750 psia.

The SITs are not required to be OPERABLE when pressurizer pressure is < 1750 psia. Therefore, in accordance with CTS 3.0.2 (ITS LCO 3.0.2), when St. Lucie Unit 1 and Unit 2 Page 5 of 7

DISCUSSION OF CHANGES ITS 3.5.1, SAFETY INJECTION TANKS (SITs) pressurizer pressure is < 1750 psia, the requirements in PSL Unit 1 CTS 4.5.1.d and PSL Unit 2 CTS 4.5.1.1.d are no longer required. Similarly, DOC A02 changes the end state in CTS 3.5.1 Actions a. and b. from MODE 4 to MODE 3 with pressurizer pressure < 1750 psia. This changes the CTS by relocating the requirements in the PSL Unit 1 CTS 4.5.1.d and PSL Unit 2 CTS 4.5.1.1.d.

The removal of SIT requirements when in MODE 3 with pressurizer pressure

< 1750 psia is acceptable because this type of information is not necessary to be included in the Technical Specifications in order to provide adequate protection of public health and safety. The ITS retains the requirements for SITs to be OPERABLE when in MODES 1, 2, and 3 with pressurizer pressure 1750 psia.

Also, this change is acceptable because these types of procedural details will be adequately controlled in the TRM. The TRM is incorporated by reference into the UFSAR and any changes to the TRM are made under 10 CFR 50.59, which ensures changes are properly evaluated. This change is designated as a less restrictive removal of detail change because these SIT requirements are not required by the CTS 3.5.1 and ITS 3.5.1 Applicability, that being MODES 1 and 2, and MODE 3 with pressurizer pressure 1750 psia.

LA05 Unit 2 only: Unit 2 CTS 4.5.1.1.c requires verification that the power be removed from each SIT isolation valve operator when RCS pressure is above 700 psia. ITS SR 3.5.1.5 requires verification that power be removed from each SIT isolation valve operator. This changes the CTS by deleting the specific pressure at which power be removed from the SIT isolation valve operators.

The purpose of the CTS requirement is to ensure power is removed from each SIT isolation valve operator when RCS pressure is above a specific value to further ensure that an active failure could not result in the undetected closure of an SIT motor operated isolation valve. This pressure value is typically above the pressure the SITs are required to be OPERABLE. For instance, the ISTS 3.5.1 Applicability is, in part, with pressurizer pressure 700 psia and ISTS SR 3.5.1.5 requires power to be removed from the isolation valve operator 2000 psia. Per the requirements of CTS 4.0.1 (ITS SR 3.0.1) and CTS 4.0.4 (ITS SR 3.0.4), SRs must be met prior to entry into the Applicability, which in the case of CTS 3.5.1 (ITS LCO 3.5.1) is MODES 1 and 2, and MODE 3 with pressurizer pressure 1750 psia. Conversely, as stated in the ITS Bases of SR 3.0.1, Surveillances do not have to be performed when the unit is in a MODE or other specified condition for which the requirements of the associated LCO are not applicable.

Therefore, it is unnecessary to specifically require power to the valve operator be removed in MODE 3 with RCS pressure 700 psia. Unit 2 CTS 3.5.1 Applicability does not require the SITs to be OPERABLE until in at least MODE 3 with pressurizer pressure 1750 psia. As such, this additional wording has been removed from Unit 2 ITS SR 3.5.1.5. This changes the CTS by relocating this requirement in CTS 3.5.1 to the Technical Requirements Manual.

The removal of this SIT requirement when in MODE 3 with pressurizer pressure

< 1750 psia is acceptable because this type of information is not necessary to be included in the Technical Specifications in order to provide adequate protection of public health and safety. The ITS retains the requirements for SITs to be OPERABLE when in MODES 1, 2, and 3 with pressurizer pressure 1750 psia.

When pressurizer pressure is below 1750 psia the ECCS pumps can provide St. Lucie Unit 1 and Unit 2 Page 6 of 7

DISCUSSION OF CHANGES ITS 3.5.1, SAFETY INJECTION TANKS (SITs) adequate injection to ensure that peak clad temperature remains below the 10 CFR 50.46 limit of 2200°F. Therefore, the SITs are not required to be OPERABLE and the SIT motor operated isolation valves may be closed to isolate the SITs from the RCS during plant shutdown or startup. Also, this change is acceptable because these types of procedural details will continue to be controlled in the TRM. The TRM is incorporated by reference into the UFSAR and any changes to the TRM are made under 10 CFR 50.59, which ensures changes are properly evaluated. This change is designated as a less restrictive removal of detail change because these SIT requirements are not required by the CTS 3.5.1 and ITS 3.5.1 Applicability, that being MODES 1 and 2, and MODE 3 with pressurizer pressure 1750 psia.

LESS RESTRICTIVE CHANGES None St. Lucie Unit 1 and Unit 2 Page 7 of 7

Improved Standard Technical Specifications (ISTS) Markup and Justification for Deviations (JFDs)

CTS SITs 3.5.1 3.5 EMERGENCY CORE COOLING SYSTEMS (ECCS) 3.5.1 Safety Injection Tanks (SITs)

LCO 3.5.1 LCO 3.5.1 [Four] SITs shall be OPERABLE. 2 1750

3.5.1 APPLICABILITY

MODES 1 and 2, Applicability MODE 3 with pressurizer pressure [700] psia. 2 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME ACTION A. One SIT inoperable due A.1 Restore SIT to OPERABLE 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months 3.5.1.a to boron concentration status.

not within limits.

OR ACTION One SIT inoperable due 3.5.1.a to the inability to verify level or pressure.

B. One SIT inoperable for B.1 Restore SIT to OPERABLE 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months reasons other than status.

Condition A.

ACTION C. Required Action and C.1 Be in MODE 3. 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months 3.5.1.a. associated Completion 3.5.1.b Time of Condition A or B AND not met.

C.2 Reduce pressurizer 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months pressure to < [700] psia. 2 1750 ACTION D. Two or more SITs D.1 Enter LCO 3.0.3. Immediately 3.5.1.b inoperable.

Combustion Engineering STS 3.5.1-1 Rev. 5.0 1

St. Lucie - Unit 1 Amendment XXX

CTS SITs 3.5.1 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY LCO 3.5.1.a SR 3.5.1.1 Verify each SIT isolation valve is fully open. [ 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months SR 4.5.1.1.a.2 2 OR In accordance with the Surveillance Frequency Control Program ]

LCO 3.5.1.b SR 3.5.1.2 Verify borated water volume in each SIT is [ 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months SR 4.5.1.1.a.1 [28% narrow range (1802 cubic feet) and 2

72% narrow range (1914 cubic feet)]. OR 1170 1090 In accordance with the Surveillance Frequency Control Program ]

LCO 3.5.1.d SR 3.5.1.3 Verify nitrogen cover pressure in each SIT is [ 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months SR 4.5.1.1.a.1 [615] psig and [655] psig. 2 230 280 OR In accordance with the Surveillance Frequency Control Program ]

Combustion Engineering STS 3.5.1-2 Rev. 5.0 1

St. Lucie - Unit 1 Amendment XXX

CTS SITs 3.5.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY LCO 3.5.1.c SR 3.5.1.4 Verify boron concentration in each SIT is [ 31 days SR 4.5.1.1.b [1500] ppm and [2800] ppm.

DOC M01 2 1900 2200 OR In accordance with the Surveillance Frequency Control Program ]

AND

NOTE--------

Only required to be performed for affected SIT Once within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months after each solution volume increase of [1]% 2 of tank volume that is not the result of addition from the refueling water tank SR 4.5.1.1.c SR 3.5.1.5 Verify power is removed from each SIT isolation [ 31 days 2 valve operator when pressurizer pressure is

[2000] psia. OR 3 In accordance with the Surveillance Frequency Control Program ]

Combustion Engineering STS 3.5.1-3 Rev. 5.0 1

St. Lucie - Unit 1 Amendment XXX

CTS SITs 3.5.1 3.5 EMERGENCY CORE COOLING SYSTEMS (ECCS) 3.5.1 Safety Injection Tanks (SITs)

LCO 3.5.1 LCO 3.5.1 [Four] SITs shall be OPERABLE. 2 1750

3.5.1 APPLICABILITY

MODES 1 and 2, Applicability MODE 3 with pressurizer pressure [700] psia. 2 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME ACTION A. One SIT inoperable due A.1 Restore SIT to OPERABLE 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months 3.5.1.a to boron concentration status.

not within limits.

OR ACTION One SIT inoperable due 3.5.1.a to the inability to verify level or pressure.

B. One SIT inoperable for B.1 Restore SIT to OPERABLE 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months reasons other than status.

Condition A.

ACTION C. Required Action and C.1 Be in MODE 3. 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months 3.5.1.a. associated Completion 3.5.1.b Time of Condition A or B AND not met.

C.2 Reduce pressurizer 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months pressure to < [700] psia. 2 1750 ACTION D. Two or more SITs D.1 Enter LCO 3.0.3. Immediately 3.5.1.b inoperable.

Combustion Engineering STS 3.5.1-1 Rev. 5.0 1

St. Lucie - Unit 2 Amendment XXX

CTS SITs 3.5.1 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY LCO 3.5.1.a SR 3.5.1.1 Verify each SIT isolation valve is fully open. [ 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months SR 4.5.1.1.a.2 2

OR In accordance with the Surveillance Frequency Control Program ]

LCO 3.5.1.b SR 3.5.1.2 Verify borated water volume in each SIT is [ 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months SR 4.5.1.1.a.1 [28% narrow range (1802 cubic feet) and 2 72% narrow range (1914 cubic feet)]. OR 1556 1420 In accordance with the Surveillance Frequency Control Program ]

LCO 3.5.1.d SR 3.5.1.3 Verify nitrogen cover pressure in each SIT is [ 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months SR 4.5.1.1.a.1 [615] psig and [655] psig. 2 500 650 OR In accordance with the Surveillance Frequency Control Program ]

Combustion Engineering STS 3.5.1-2 Rev. 5.0 1

St. Lucie - Unit 2 Amendment XXX

CTS SITs 3.5.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY LCO 3.5.1.c SR 3.5.1.4 Verify boron concentration in each SIT is [ 31 days SR 4.5.1.1.b [1500] ppm and [2800] ppm. 2 1900 2200 OR In accordance with the Surveillance Frequency Control Program ]

AND

NOTE--------

Only required to be performed for affected SIT Once within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months after each solution volume increase of [1]% 2 of tank volume that is not the result of addition from the refueling water tank SR 4.5.1.1.c SR 3.5.1.5 Verify power is removed from each SIT isolation [ 31 days 2 valve operator when pressurizer pressure is

[2000] psia. OR 3 In accordance with the Surveillance Frequency Control Program ]

Combustion Engineering STS 3.5.1-3 Rev. 5.0 1

St. Lucie - Unit 2 Amendment XXX

JUSTIFICATION FOR DEVIATIONS ITS 3.5.1, SAFETY INJECTION TANKS (SITs)

1. Changes are made (additions, deletions, and/or changes) to the ISTS that reflect the plant specific nomenclature, number, reference, system description, analysis, licensing basis, or licensing basis description.

2. The ISTS contains bracketed information and/or values that are generic to all Combustion Engineering vintage plants. The brackets are removed, and the proper plant specific information/value is provided. This is acceptable since the information/value is changed to reflect the current licensing basis.

3. The purpose ISTS 3.5.1.5 is to ensure power is removed from each SIT isolation valve operator when RCS pressure is above a specified value to further ensure that an active failure could not result in the undetected closure of an SIT motor operated isolation valve. This pressure value is intended to be above the pressure the SITs are required to be OPERABLE. However, the CTS Applicability is MODES 1 and 2, and MODE 3 with pressurizer pressure 1750 psia and the equivalent Surveillances (Unit 1 CTS 4.5.1.c and Unit 2 CTS 4.5.1.1.c) require power to be removed to the isolation valve operators above 1750 psia or less. Per the requirements of ISTS SR 3.0.1 and ISTS SR 3.0.4, SRs must be met prior to entry into the Applicability, which in the case of ITS LCO 3.5.1 is MODES 1 and 2, and MODE 3 with pressurizer pressure 1750 psia. Conversely, as stated in the ITS Bases of SR 3.0.1, Surveillances do not have to be performed when the unit is in a MODE or other specified condition for which the requirements of the associated LCO are not applicable. Therefore, it is unnecessary to specifically require power to the valve operator be removed "when in MODE 3 with pressure 1750 psia" and this additional wording has been removed.

St. Lucie Unit 1 and Unit 2 Page 1 of 1

Improved Standard Technical Specifications (ISTS) Bases Markup and Justification for Deviations (JFDs)

SITs B 3.5.1 B 3.5 EMERGENCY CORE COOLING SYSTEMS (ECCS)

B 3.5.1 Safety Injection Tanks (SITs)

BASES BACKGROUND The functions of the [four] SITs are to supply water to the reactor vessel 2 during the blowdown phase of a loss of coolant accident (LOCA), to provide inventory to help accomplish the refill phase that follows thereafter, and to provide Reactor Coolant System (RCS) makeup for a small break LOCA.

The blowdown phase of a large break LOCA is the initial period of the transient during which the RCS departs from equilibrium conditions, and heat from fission product decay, hot internals, and the vessel continues to be transferred to the reactor coolant. The blowdown phase of the transient ends when the RCS pressure falls to a value approaching that of the containment atmosphere.

The refill phase of a LOCA follows immediately where reactor coolant inventory has vacated the core through steam flashing and ejection out through the break. The core is essentially in adiabatic heatup. The balance of the SITs' inventory is then available to help fill voids in the lower plenum and reactor vessel downcomer to establish a recovery level at the bottom of the core and ongoing reflood of the core with the addition of safety injection (SI) water.

The SITs are pressure vessels partially filled with borated water and pressurized with nitrogen gas. The SITs are passive components, since no operator or control action is required for them to perform their function.

Internal tank pressure is sufficient to discharge the contents to the RCS, if RCS pressure decreases below the SIT pressure.

Each SIT is piped into one RCS cold leg via the injection lines utilized by the High Pressure Safety Injection and Low Pressure Safety Injection (HPSI and LPSI) systems. Each SIT is isolated from the RCS by a motor operated isolation valve and two check valves in series. The motor 1 operated isolation valves are normally open, with power removed from the valve motor to prevent inadvertent closure prior to or during an accident.

The SIT gas and water volumes, gas pressure, and outlet pipe size are selected to allow three of the four SITs to partially recover the core before significant clad melting or zirconium water reaction can occur following a LOCA. The need to ensure that three SITs are adequate for this function is consistent with the LOCA assumption that the entire contents of one SIT will be lost via the break during the blowdown phase of a LOCA.

Combustion Engineering STS B 3.5.1-1 Rev. 5.0 1 St. Lucie - Unit 1 Revision XXX

SITs B 3.5.1 BASES APPLICABLE The SITs are taken credit for in both the large and small break LOCA SAFETY analyses at full power (Ref. 1). These are the Design Basis Accidents ANALYSES (DBAs) that establish the acceptance limits for the SITs. Reference to the analyses for these DBAs is used to assess changes to the SITs as they relate to the acceptance limits.

In performing the LOCA calculations, conservative assumptions are made concerning the availability of SI flow. These assumptions include signal generation time, equipment starting times, and delivery time due to system piping. In the early stages of a LOCA with a loss of offsite power, the SITs provide the sole source of makeup water to the RCS. (The assumption of a loss of offsite power is required by regulations.) This is because the LPSI pumps, HPSI pumps, and charging pumps cannot deliver flow until the diesel generators (DGs) start, come to rated speed, and go through their timed loading sequence. In cold leg breaks, the entire contents of one SIT are assumed to be lost through the break during the blowdown and reflood phases.

The limiting large break LOCA is a double ended guillotine cold leg break at the discharge of the reactor coolant pump.

During this event, the SITs discharge to the RCS as soon as RCS pressure decreases to below SIT pressure. As a conservative estimate, no credit is taken for SI pump flow until the SITs are empty. This results in a minimum effective delay of over 60 seconds, during which the SITs must provide the core cooling function. The actual delay time does not exceed 30 seconds. No operator action is assumed during the blowdown stage of a large break LOCA.

The worst case small break LOCA also assumes a time delay before pumped flow reaches the core. For the larger range of small breaks, the rate of blowdown is such that the increase in fuel clad temperature is terminated solely by the SITs, with pumped flow then providing continued cooling. As break size decreases, the SITs and HPSI pumps both play a part in terminating the rise in clad temperature. As break size continues to decrease, the role of the SITs continues to decrease until they are not required, and the HPSI pumps become solely responsible for terminating the temperature increase.

This LCO helps to ensure that the following acceptance criteria, established by 10 CFR 50.46 (Ref. 2) for the ECCS, will be met following a LOCA:

Combustion Engineering STS B 3.5.1-2 Rev. 5.0 1 St. Lucie - Unit 1 Revision XXX

SITs B 3.5.1 BASES APPLICABLE SAFETY ANALYSES (continued)

a. Maximum fuel element cladding temperature is 2200°F,

b. Maximum cladding oxidation is 0.17 times the total cladding thickness before oxidation,

c. Maximum hydrogen generation from a zirconium water reaction is 0.01 times the hypothetical amount that would be generated if all of the metal in the cladding cylinders surrounding the fuel, excluding the cladding surrounding the plenum volume, were to react, and

d. The core is maintained in a coolable geometry.

Since the SITs discharge during the blowdown phase of a LOCA, they do not contribute to the long term cooling requirements of 10 CFR 50.46.

Since the SITs are passive components, single active failures are not applicable to their operation. The SIT isolation valves, however, are not single failure proof; therefore, whenever the valves are open, power is removed from their operators and the switch is key locked open.

These precautions ensure that the SITs are available during an accident (Ref. 3). With power supplied to the valves, a single active failure could result in a valve closure, which would render one SIT unavailable for injection. If a second SIT is lost through the break, only two SITs would reach the core. Since the only active failure that could affect the SITs would be the closure of a motor operated outlet valve, the requirement to remove power from these eliminates this failure mode.

The minimum volume requirement for the SITs ensures that three SITs can provide adequate inventory to reflood the core and downcomer following a LOCA. The downcomer then remains flooded until the HPSI and LPSI systems start to deliver flow.

The maximum volume limit is based on maintaining an adequate gas volume to ensure proper injection and the ability of the SITs to fully discharge, as well as limiting the maximum amount of boron inventory in the SITs.

Combustion Engineering STS B 3.5.1-3 Rev. 5.0 1 St. Lucie - Unit 1 Revision XXX

SITs B 3.5.1 BASES APPLICABLE SAFETY ANALYSES (continued) 1090 A minimum of 25% narrow range level, corresponding to [1790] cubic feet 2 3 of borated water, and a maximum of 75% narrow range level, 1170 corresponding to [1927] cubic feet of borated water, are used in the safety 2 analyses as the volume in the SITs. To allow for instrument inaccuracy, a

[28]% narrow range (corresponding to [1802] cubic feet) and a [72]%

narrow range (corresponding to [1914] cubic feet) are specified. The 2 3 analyses are based upon the cubic feet requirements; the percentage figures are provided for operator use because the level indicator provided in the control room is marked in percentages, not in cubic feet.

The minimum nitrogen cover pressure requirement ensures that the contained gas volume will generate discharge flow rates during injection that are consistent with those assumed in the safety analyses.

The maximum nitrogen cover pressure limit ensures that excessive amounts of gas will not be injected into the RCS after the SITs have emptied.

230 280 A minimum pressure of [593] psig and a maximum pressure of [632] psig 4

are used in the analyses. To allow for instrument accuracy, a [615] psig minimum and [655] psig maximum are specified. The maximum 2200 allowable boron concentration of [2800] ppm is based upon boron 2 precipitation limits in the core following a LOCA. Establishing a maximum limit for boron is necessary since the time at which boron precipitation would occur in the core following a LOCA is a function of break location, break size, the amount of boron injected into the core, and the point of ECCS injection. Post LOCA emergency procedures directing the operator to establish simultaneous hot and cold leg injection are based on the worst case minimum boron precipitation time. Maintaining the maximum SIT boron concentration within the upper limit ensures that the SITs do not invalidate this calculation. An excessive boron concentration in any of the borated water sources used for injection during a LOCA could result in boron precipitation earlier than predicted.

1900 The minimum boron requirements of [1500] ppm are based on beginning 2 of life reactivity values and are selected to ensure that the reactor will remain subcritical during the reflood stage of a large break LOCA. During a large break LOCA, all control element assemblies (CEAs) are assumed not to insert into the core, and the initial reactor shutdown is Combustion Engineering STS B 3.5.1-4 Rev. 5.0 1 St. Lucie - Unit 1 Revision XXX

SITs B 3.5.1 BASES APPLICABLE SAFETY ANALYSES (continued) accomplished by void formation during blowdown. Sufficient boron concentration must be maintained in the SITs to prevent a return to criticality during reflood. Although this requirement is similar to the basis for the minimum boron concentration of the refueling water tank (RWT), 1 the minimum SIT concentration is lower than that of the RWT since the SITs need not account for dilution by the RCS.

The SITs satisfy Criterion 3 of 10 CFR 50.36(c)(2)(ii).

LCO The LCO establishes the minimum conditions required to ensure that the SITs are available to accomplish their core cooling safety function following a LOCA. [Four] SITs are required to be OPERABLE to ensure 2

that 100% of the contents of [three] of the SITs will reach the core during a LOCA.

This is consistent with the assumption that the contents of one tank spill through the break. If the contents of fewer than three tanks are injected during the blowdown phase of a LOCA, the ECCS acceptance criteria of 10 CFR 50.46 (Ref. 2) could be violated.

For an SIT to be considered OPERABLE, the isolation valve must be fully open, power removed above [2000] psig, and the limits established in the 2 1750 psia SR for contained volume, boron concentration, and nitrogen cover pressure must be met.

1750 APPLICABILITY In MODES 1 and 2, and MODE 3 with RCS pressure 700 psia, the SIT 2 OPERABILITY requirements are based on an assumption of full power operation. Although cooling requirements decrease as power decreases, the SITs are still required to provide core cooling as long as elevated RCS pressures and temperatures exist.

1750 1750 This LCO is only applicable at pressures 700 psia. Below 700 psia, the 2 rate of RCS blowdown is such that the ECCS pumps can provide adequate injection to ensure that peak clad temperature remains below the 10 CFR 50.46 (Ref. 2) limit of 2200°F.

1750 In MODE 3, at pressures < 700 psia, and in MODES 4, 5, and 6, the SIT motor operated isolation valves are closed to isolate the SITs from the 5

during unit shutdown and startup RCS. This allows RCS cooldown and depressurization without discharging the SITs into the RCS or requiring depressurization of the SITs.

Combustion Engineering STS B 3.5.1-5 Rev. 5.0 1 St. Lucie - Unit 1 Revision XXX

SITs B 3.5.1 BASES ACTIONS A.1 If the boron concentration of one SIT is not within limits, it must be returned to within the limits within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . In this condition, ability to maintain subcriticality or minimum boron precipitation time may be reduced, but the reduced concentration effects on core subcriticality during reflood are minor. Boiling of the ECCS water in the core during reflood concentrates the boron in the saturated liquid that remains in the core. In addition, the volume of the SIT is still available for injection.

Since the boron requirements are based on the average boron concentration of the total volume of three SITs, the consequences are less severe than they would be if an SIT were not available for injection.

Thus, 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months is allowed to return the boron concentration to within limits.

The combination of redundant level and pressure instrumentation for any single SIT provides sufficient information so that it is not worthwhile to always attempt to correct drift associated with one instrument, with the resulting radiation exposures during entry into containment, as there is sufficient time to repair one in the event that a second one became inoperable. Because these instruments do not initiate a safety action, it is reasonable to extend the allowable outage time for them. While technically inoperable, the SIT will be available to fulfill its safety function during this time and, thus, this Completion Time results in a negligible increase in risk.

B.1 If one SIT is inoperable, for reasons other than boron concentration or the inability to verify level or pressure, the SIT must be returned to OPERABLE status within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . In this Condition, the required contents of three SITs cannot be assumed to reach the core during a LOCA as is assumed in Appendix K (Ref. 5).

CE NPSD-994 (Ref. 6) provides a series of deterministic and probabilistic findings that support the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion Time as having no affect on risk as compared to shorter periods for restoring the SIT to OPERABLE status.

Combustion Engineering STS B 3.5.1-6 Rev. 5.0 1 St. Lucie - Unit 1 Revision XXX

SITs B 3.5.1 BASES ACTIONS (continued)

C.1 and C.2 If the SIT cannot be restored to OPERABLE status within the associated Completion Time, the plant must be brought to a MODE in which the LCO does not apply. To achieve this status, the plant must be brought to at least MODE 3 within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and pressurizer pressure reduced to

< 700 psia within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months . The allowed Completion Times are 2 1750 reasonable, based on operating experience, to reach the required plant conditions from full power conditions in an orderly manner and without challenging plant systems.

D.1 If more than one SIT is inoperable, the unit is in a condition outside the accident analyses. Therefore, LCO 3.0.3 must be entered immediately.

SURVEILLANCE SR 3.5.1.1 REQUIREMENTS before power is removed from its valve operator Verification that each SIT isolation valve is fully open, as indicated in the control room, ensures that SITs are available for injection and ensures timely discovery if a valve should be partially closed. If an isolation valve is not fully open, the rate of injection to the RCS would be reduced.

Although a motor operated valve should not change position with power removed, a closed valve could result in not meeting accident analysis assumptions. [ A 12 hour1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months Frequency is considered reasonable in view of other administrative controls that ensure the unlikelihood of a 2 mispositioned isolation valve.

OR The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.

REVIEWERS NOTE-----------------------------------

Plants controlling Surveillance Frequencies under a Surveillance Frequency Control Program should utilize the appropriate Frequency 2 description, given above, and the appropriate choice of Frequency in the Surveillance Requirement.

]

Combustion Engineering STS B 3.5.1-7 Rev. 5.0 1 St. Lucie - Unit 1 Revision XXX

SITs B 3.5.1 BASES SURVEILLANCE REQUIREMENTS (continued)

SR 3.5.1.2 and SR 3.5.1.3 SIT borated water volume and nitrogen cover pressure should be verified to be within specified limits in order to ensure adequate injection during a LOCA. [ Due to the static design of the SITs, a 12 hour1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months Frequency usually allows the operator sufficient time to identify changes before the 2 limits are reached. Operating experience has shown this Frequency to be appropriate for early detection and correction of off normal trends.

OR The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.

REVIEWERS NOTE-----------------------------------

Plants controlling Surveillance Frequencies under a Surveillance Frequency Control Program should utilize the appropriate Frequency 2

description, given above, and the appropriate choice of Frequency in the Surveillance Requirement.

]

SR 3.5.1.4 Thirty-one days is reasonable for verification to determine that each SIT's boron concentration is within the required limits, because the static design of the SITs limits the ways in which the concentration can be changed. 2

[ The 31 day Frequency is adequate to identify changes that could occur from mechanisms such as stratification or inleakage. Sampling the affected SIT within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months after a 1% volume increase will identify whether inleakage has caused a reduction in boron concentration to below the required limit. It is not necessary to verify boron concentration the boron concentration of if the added water is from the RWT, because the water contained in the 6 RWT is within the SIT boron concentration requirements. This is consistent with the recommendations of NUREG-1366 (Ref. 4).

and assumes the RWT has not been diluted since the last time OR the RWT boron concentration was verified to be within limits.

The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.

Combustion Engineering STS B 3.5.1-8 Rev. 5.0 1 St. Lucie - Unit 1 Revision XXX

SITs B 3.5.1 BASES SURVEILLANCE REQUIREMENTS (continued)

REVIEWERS NOTE-----------------------------------

Plants controlling Surveillance Frequencies under a Surveillance Frequency Control Program should utilize the appropriate Frequency description, given above, and the appropriate choice of Frequency in the 2 Surveillance Requirement.

]

SR 3.5.1.5 Verification that power is removed from each SIT isolation valve operator when the pressurizer pressure is 2000 psia ensures that an active 2 failure could not result in the undetected closure of an SIT motor operated isolation valve. If this were to occur, only two SITs would be available for injection, given a single failure coincident with a LOCA. [ Since R

installation and removal of power to the SIT isolation valve operators is conducted under administrative control, the 31 day Frequency was 2 chosen to provide additional assurance that power is removed.

OR The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.

REVIEWERS NOTE-----------------------------------

Plants controlling Surveillance Frequencies under a Surveillance Frequency Control Program should utilize the appropriate Frequency description, given above, and the appropriate choice of Frequency in the Surveillance Requirement.

]

This SR allows power to be supplied to the motor operated isolation valves when RCS pressure is < 2000 psia, thus allowing operational flexibility by avoiding unnecessary delays to manipulate the breakers 1 during unit startups or shutdowns.

Combustion Engineering STS B 3.5.1-9 Rev. 5.0 1 St. Lucie - Unit 1 Revision XXX

SITs B 3.5.1 BASES U Chapter 15 REFERENCES 1. FSAR, Section [6.3]. 1 2

2. 10 CFR 50.46.

U Section 6.3 1 2

3. FSAR, Chapter [15].

4. Draft NUREG-1366, February 1990.

5. 10 CFR 50 Appendix K.

6. CE NPSD-994, "CEOG Joint Applications Report for Safety Injection Tank AOT/STI Extension," May 1995.

Combustion Engineering STS B 3.5.1-10 Rev. 5.0 1 St. Lucie - Unit 1 Revision XXX

SITs B 3.5.1 B 3.5 EMERGENCY CORE COOLING SYSTEMS (ECCS)

B 3.5.1 Safety Injection Tanks (SITs)

BASES BACKGROUND The functions of the [four] SITs are to supply water to the reactor vessel 2 during the blowdown phase of a loss of coolant accident (LOCA), to provide inventory to help accomplish the refill phase that follows thereafter, and to provide Reactor Coolant System (RCS) makeup for a small break LOCA.

The blowdown phase of a large break LOCA is the initial period of the transient during which the RCS departs from equilibrium conditions, and heat from fission product decay, hot internals, and the vessel continues to be transferred to the reactor coolant. The blowdown phase of the transient ends when the RCS pressure falls to a value approaching that of the containment atmosphere.

The refill phase of a LOCA follows immediately where reactor coolant inventory has vacated the core through steam flashing and ejection out through the break. The core is essentially in adiabatic heatup. The balance of the SITs' inventory is then available to help fill voids in the lower plenum and reactor vessel downcomer to establish a recovery level at the bottom of the core and ongoing reflood of the core with the addition of safety injection (SI) water.

The SITs are pressure vessels partially filled with borated water and pressurized with nitrogen gas. The SITs are passive components, since no operator or control action is required for them to perform their function.

Internal tank pressure is sufficient to discharge the contents to the RCS, if RCS pressure decreases below the SIT pressure.

Each SIT is piped into one RCS cold leg via the injection lines utilized by the High Pressure Safety Injection and Low Pressure Safety Injection (HPSI and LPSI) systems. Each SIT is isolated from the RCS by a motor operated isolation valve and two check valves in series. The motor 1 operated isolation valves are normally open, with power removed from the valve motor to prevent inadvertent closure prior to or during an accident.

The SIT gas and water volumes, gas pressure, and outlet pipe size are selected to allow three of the four SITs to partially recover the core before significant clad melting or zirconium water reaction can occur following a LOCA. The need to ensure that three SITs are adequate for this function is consistent with the LOCA assumption that the entire contents of one SIT will be lost via the break during the blowdown phase of a LOCA.

Combustion Engineering STS B 3.5.1-1 Rev. 5.0 1 St. Lucie - Unit 2 Revision XXX

SITs B 3.5.1 BASES APPLICABLE The SITs are taken credit for in both the large and small break LOCA SAFETY analyses at full power (Ref. 1). These are the Design Basis Accidents ANALYSES (DBAs) that establish the acceptance limits for the SITs. Reference to the analyses for these DBAs is used to assess changes to the SITs as they relate to the acceptance limits.

In performing the LOCA calculations, conservative assumptions are made concerning the availability of SI flow. These assumptions include signal generation time, equipment starting times, and delivery time due to system piping. In the early stages of a LOCA with a loss of offsite power, the SITs provide the sole source of makeup water to the RCS. (The assumption of a loss of offsite power is required by regulations.) This is because the LPSI pumps, HPSI pumps, and charging pumps cannot deliver flow until the diesel generators (DGs) start, come to rated speed, and go through their timed loading sequence. In cold leg breaks, the entire contents of one SIT are assumed to be lost through the break during the blowdown and reflood phases.

The limiting large break LOCA is a double ended guillotine cold leg break at the discharge of the reactor coolant pump.

During this event, the SITs discharge to the RCS as soon as RCS pressure decreases to below SIT pressure. As a conservative estimate, no credit is taken for SI pump flow until the SITs are empty. This results in a minimum effective delay of over 60 seconds, during which the SITs must provide the core cooling function. The actual delay time does not exceed 30 seconds. No operator action is assumed during the blowdown stage of a large break LOCA.

The worst case small break LOCA also assumes a time delay before pumped flow reaches the core. For the larger range of small breaks, the rate of blowdown is such that the increase in fuel clad temperature is terminated solely by the SITs, with pumped flow then providing continued cooling. As break size decreases, the SITs and HPSI pumps both play a part in terminating the rise in clad temperature. As break size continues to decrease, the role of the SITs continues to decrease until they are not required, and the HPSI pumps become solely responsible for terminating the temperature increase.

This LCO helps to ensure that the following acceptance criteria, established by 10 CFR 50.46 (Ref. 2) for the ECCS, will be met following a LOCA:

Combustion Engineering STS B 3.5.1-2 Rev. 5.0 1 St. Lucie - Unit 2 Revision XXX

SITs B 3.5.1 BASES APPLICABLE SAFETY ANALYSES (continued)

a. Maximum fuel element cladding temperature is 2200°F,

b. Maximum cladding oxidation is 0.17 times the total cladding thickness before oxidation,

c. Maximum hydrogen generation from a zirconium water reaction is 0.01 times the hypothetical amount that would be generated if all of the metal in the cladding cylinders surrounding the fuel, excluding the cladding surrounding the plenum volume, were to react, and

d. The core is maintained in a coolable geometry.

Since the SITs discharge during the blowdown phase of a LOCA, they do not contribute to the long term cooling requirements of 10 CFR 50.46.

Since the SITs are passive components, single active failures are not applicable to their operation. The SIT isolation valves, however, are not single failure proof; therefore, whenever the valves are open, power is removed from their operators and the switch is key locked open.

These precautions ensure that the SITs are available during an accident (Ref. 3). With power supplied to the valves, a single active failure could result in a valve closure, which would render one SIT unavailable for injection. If a second SIT is lost through the break, only two SITs would reach the core. Since the only active failure that could affect the SITs would be the closure of a motor operated outlet valve, the requirement to remove power from these eliminates this failure mode.

The minimum volume requirement for the SITs ensures that three SITs can provide adequate inventory to reflood the core and downcomer following a LOCA. The downcomer then remains flooded until the HPSI and LPSI systems start to deliver flow.

The maximum volume limit is based on maintaining an adequate gas volume to ensure proper injection and the ability of the SITs to fully discharge, as well as limiting the maximum amount of boron inventory in the SITs.

Combustion Engineering STS B 3.5.1-3 Rev. 5.0 1 St. Lucie - Unit 2 Revision XXX

SITs B 3.5.1 BASES APPLICABLE SAFETY ANALYSES (continued) 1420 A minimum of 25% narrow range level, corresponding to [1790] cubic feet 2 3 of borated water, and a maximum of 75% narrow range level, 1556 corresponding to [1927] cubic feet of borated water, are used in the safety 2 analyses as the volume in the SITs. To allow for instrument inaccuracy, a

[28]% narrow range (corresponding to [1802] cubic feet) and a [72]%

narrow range (corresponding to [1914] cubic feet) are specified. The 2 3 analyses are based upon the cubic feet requirements; the percentage figures are provided for operator use because the level indicator provided in the control room is marked in percentages, not in cubic feet.

The minimum nitrogen cover pressure requirement ensures that the contained gas volume will generate discharge flow rates during injection that are consistent with those assumed in the safety analyses.

The maximum nitrogen cover pressure limit ensures that excessive amounts of gas will not be injected into the RCS after the SITs have emptied.

500 650 A minimum pressure of [593] psig and a maximum pressure of [632] psig are used in the analyses. To allow for instrument accuracy, a [615] psig 4 minimum and [655] psig maximum are specified. The maximum 2200 allowable boron concentration of [2800] ppm is based upon boron 2 precipitation limits in the core following a LOCA. Establishing a maximum limit for boron is necessary since the time at which boron precipitation would occur in the core following a LOCA is a function of break location, break size, the amount of boron injected into the core, and the point of ECCS injection. Post LOCA emergency procedures directing the operator to establish simultaneous hot and cold leg injection are based on the worst case minimum boron precipitation time. Maintaining the maximum SIT boron concentration within the upper limit ensures that the SITs do not invalidate this calculation. An excessive boron concentration in any of the borated water sources used for injection during a LOCA could result in boron precipitation earlier than predicted.

1900 The minimum boron requirements of [1500] ppm are based on beginning 2 of life reactivity values and are selected to ensure that the reactor will remain subcritical during the reflood stage of a large break LOCA. During a large break LOCA, all control element assemblies (CEAs) are assumed not to insert into the core, and the initial reactor shutdown is Combustion Engineering STS B 3.5.1-4 Rev. 5.0 1 St. Lucie - Unit 2 Revision XXX