ML18102B022

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Application for Amends to Licenses DPR-70 & DPR-75, Eliminating Flow Path from RHR Sys to RCS Hot Legs as Specified in LCO 3.5.2.c.2
ML18102B022
Person / Time
Site: Salem  PSEG icon.png
Issue date: 04/25/1997
From: Storz L
Public Service Enterprise Group
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML18102B024 List:
References
LCR-S97-11, LR-N970256, NUDOCS 9705050065
Download: ML18102B022 (11)
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  • Public Service Electric and Gas Company Louis F. Storz Public Service Electric and Gas Company 609-339-5700 Senior Vice President - Nuclear Operations LR-N970256 LCR S97-11 United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 EXIGENT REQUEST FOR CHANGE TO TECHNICAL SPECIFICATIONS EMERGENCY CORE COOLING SUBSYSTEMS*

SALEM GENERATING STATION NOS. 1 AND 2 FACILITY OPERATING LICENSES DPR-70 AND DPR-75 DOCKET NOS. 50-272 AND 50-311 Gentlemen:

In accordance with 10CFR50.90,* Public Service Electric & Gas (PSE&G) Company requests a revision to the Technical Specifications (TS) for the Salem Generating Station Unit Nos. 1 and 2. In accordance with 10CFR50.91 (b) (1), a copy of this submittal has been sent to the State of New Jersey.

The proposed TS changes contained herein represents a change to Specification 3.5.2, "ECCS Subsystems - T" 9 ~ 350°F." This change eliminates the flow path from the Residual Heat Removal (RHR) system to the Reactor Coolant System (RCS) hot legs as specified in Limiting Condition for Operation (LCO) 3.5.2.c.2.

PSE&G requests this change to ensure RHR pump operation during all hot leg recirculation configurations assuming worst case single failures that could result in increased flows following a Loss of Coolant Accident (LOCA) during hot leg recirculation.

This reduction in RHR pump flow during hot leg recirculation will also ensure that the net positive suction head (NPSH) for the RHR pumps is maintained.

The proposed changes have been evaluated in accordance with 10CFR50.91(a) (1), using the criteria in 10CFR50.92(c), and PSE&G has concluded that this request involves no significant hazards considerations.

The basis for the requested change is provided in Attachment 1.

A 10C~R50.92 evaluation with a determination of no significant hazards consideration is provided in Attachment 2. The marked up TS pages affected by the proposed changes are provided in Attachment 3.

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.Document Control Desk APR 2 5 7997 LR-N970256 Upon NRC approval of this proposed change, PSE&G requests that the amendment be made effective on the date of issuance, but provide for implementation prior to entry into Mode 3 from the current outages for Salem Units 1 and 2 .. Because the necessity to revise the technical specifications was recently identified during inspection 311/97-11 and may be needed prior to entry into Mode 3 on Salem Unit 2, PSE&G is requesting that this request be processed on an exigent basis.

Should you have any questions regarding this request, we will be pleased to discuss them with you.

Sincerely, Affidavit Attachments (3)

C Mr. H. J. Miller, Administrator - Region I U. S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Mr. L. Olshan, Licensing Project Mahager - Salem U. S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 14E21 Rockville, MD 20852 Mr. C. Marschall (X24)

USNRC Senior Resident Inspector - Salem Mr. K. Tosch, Manager IV Bureau of Nuclear Engineering 33 Arctic Parkway CN 415 Trenton, NJ 08625

.Document Control Desk

  • LR-N970256 BJT BC Senior Vice President - Nuclear Engineering (N19)

General Manager - Salem Operations (SOS)

Director - QA/NSR (XOl}

Manager - Nuclear Business Relations (N28}

Manager - Salem Operations (SOl}

Director System Engineering - Salem (S02}

Manager - Nuclear Safety Review (N38}

Manager - Licensing & Regulation (X09)

Principal Engineer [Salem] Operational Licensing (X09}

Station Licensing Engineer - Salem (X09}

Perry Robinson, Esq.

J. Keenan, Esq.

Records Management (N21)

Microfilm Copy Files Nos. 1.2.1 (Salem), 2.3 (LCR S97-11)

COUNTY OF SALEM L. F. Storz, being duly sworn according to law deposes and says:

I am Senior Vice President - Nuclear Operations of Public Service Electric and Gas Company, and as such, I find the matters set forth in the above referenced letter, concerning Salem Generating Station, Units 1 and 2, are true to the best of my knowledge, information and belief.

Subscrib~hand Sw~ore me thisd.2: day of ~ , 1997 KIMBERL VJO BROWN NOTARY PUBLIC OF NEW JERSEY My Commission Expires April 21, 1998 My Commission expires on

Document Control Desk

  • Attachment 1
  • LR-970256 LCR S97-11 SALEM GENERATING STATION UNIT NOS. 1 AND 2 FACILITY OPERATING LICENSES DPR-70 AND DPR-75 DOCKET NOS. 50-272 AND 50-311 CHANGE TO TECHNICAL SPECIFICATIONS EMERGENCY CORE COOLING SUBSYSTEMS BASIS FOR REQUESTED CHANGE REQUESTED CHANGE AND PURPOSE The requested change to Technical Specification 3.5.2, "ECCS Subsystems - Tavg :<>:: 350 ° F," consists of deleting Limiting Condition for Operation (LCO) 3.5.2.c.2. This change eliminates the flow path from the Residual Heat Removal (RHR) system to the Reactor Coolant System (RCS) hot legs as specified in Limiting Condition for Operation (LCO) 3.5.2.c.2 for Modes 1 - 3.

PSE&G requests this change to ensure RHR pump operation during all hot leg recirculation configurations assuming worst case single failures that could result in increased flows following a Loss of Coolant Accident (LOCA) during hot leg recirculation.

This reduction in RHR pump flow during hot leg recirculation will reduce the net positive suction head (NPSH) required for the RHR pumps and provide additional margin to ensure that the RHR pumps will have adequate NPSH during hot leg recirculation.

There are no changes being proposed to the TS 3.5.3 for operation of the ECCS in Mode 4.

BACKGROUND The Emergency Operating Procedures (EOPs) are used by the operators to align the Emergency Core Cooling System (ECCS) to hot leg recirculation mode of accident mitigation approximately 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br /> after transfer to cold leg recirculation following a LOCA. Hot leg recirculation is initiated to assure termination of boiling and control the boron concentration in the reactor vessel. Prior to the EOP changes performed in 1994, the ECCS system would be aligned for hot leg recirculation as follows:

  • One RHR train would be realigned to deliver flow to only the suction of the high-head ECCS pumps (low head flow to the cold leg was isolated but both RH19 valves were open so flow also went to the hot leg) .
  • The other RHR train was realigned from supplying containment spray and cold leg injection to low-head hot leg injection through the RH26 valve while maintaining continuous flow to the high-head ECCS pumps.

Page 1 of 3

  • Attachment 1 Document Control Desk
  • LR-970256 LCR S97-11
  • Both intermediate head Safety Injection pumps would be realigned to deliver flow to the RCS hot legs via separate discharge headers (each header supplies two different RCS hot legs).

In 1994, Westinghouse informed PSE&G that a high RHR pump flow condition can occur during hot leg recirculation due to 1) "loop around" flow should a RHR pump failure occur at the point when both SJ45 valves (high head supply) are open, 2) higher Intermediate Head Safety Injection (IHSI) pump flow due to operation of both hot leg discharge headers (compared to a common cold leg discharge header), 3) a potential higher flow capability in the RHR hot leg header (compared to either RHR cold leg header), and 4) ECCS high head and intermediate head suction boost (which increases the flows through these pumps).

To eliminate the potential for a high RHR pump flow condition, changes to the EOPs were implemented in 1994 to eliminate the procedure steps associated with the opening of the RHR hot leg injection path (via RH26). The elimination of this flow path reduced the amount of flow delivered by the RHR pumps during hot leg recirculation. Changes to the Technical Specifications as a result of ECCS suction boost flow are being addressed by LCR S95-37 svbmitted to the NRC on March 4, 1997.

JUSTIFICATION OF REQUESTED CHANGES The reduction in hot leg injection flow (elimination of RH26 injection path) capability was evaluated by Westinghouse to confirm sufficient ECCS flow to remove core decay heat without creating superheated steam. Hot leg recirculation occurs approximately 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br /> after the LOCA. At initiation of hot leg recirculation, the RCS pressure is at equilibrium with the containment pressure, which is conservatively assumed to be at 25.0 psig. At this pressure, the enthalpy of saturated steam is 1160.1 BTU/lbm, and 208.52 BTU/lbm for saturated liquid. Decay heat generation at this time is 24,540 BTU/sec. Therefore, the required hot leg injection flowrate to prevent superheat is 24,540/(1160.1-208.52)= 25.77 lbm/sec. The flow delivered by one Intermediate Head Safety Injection (IHSI) pump to two hot legs is 76.03 lbm/sec at a backpressure of 25.0 psig. For the break locations considered for long-term transients, nearly all of this flow will enter the vessel and will be available to cool the core. Additional cooling will be provided by simultaneous cold leg injection flow from the high head pumps. Therefore sufficient injection flow exists from the IHSI pumps alone to prevent superheat and the change to the hot leg recirculation does not affect the LOCA mass and energy or containment integrity analysis.

Page 2 of 3

Document Control Desk

  • Attachment 1
  • LR-970256 LCR S97-11 The post LOCA hot leg recirculation time is included in the EOPs to ensure no boron precipitation in the reactor vessel occurs as a result of boiling and consequential boron concentration buildup in the core following a LOCA. Based on the power level prior to the LOCA, and water volumes and boron concentrations contained in the RCS, Refueling Water Storage Tank (RWST) and the accumulators, Westinghouse analysis (letter PSE-86-620 in support of Amendment 88 for Unit 1 and Amendment 55 for Unit 2) determined the switchover to hot leg recirculation time as 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br />. The closure of the RH26 flow path does not impact the assumptions used for this analysis. A verification of the flow required to prevent an increase of core boron concentration with the closure of the RHR system hot leg flow path (RH26) was performed. The high head and intermediate head Safety Injection system flows were determined to provide adequate hot and cold leg flow after initiation of hot leg recirculation to prevent the increase of core boron concentration.

A failure modes analysis was performed by Westinghouse (SECL 291, Rev. 1) that states that with elimination of the RHR hot leg flow path, the ECCS continues to meet the limiting design basis hot leg flow requirement assuming a single active or passive failure which can result in operation of a single IHSI pump aligned for hot leg recirculation.

The change presented above does not affect the use of the RHR flow path to the RCS hot legs during Mode 4. Since there are no specific operability requirements for the Safety Injection system (SIS) and the SIS may not be available in Mode 4, the hot leg injection flow path through RH26 will continue to be used to mitigate Mode 4 LOCAs.

CONCLUSIONS The proposed change for eliminating the RHR hot leg discharge path specified in LCO 3.5.2.c.2 does not impact the ability of the Emergency Core Cooling System to meet the hot leg injection flow required in the accident analysis to remove core decay heat without creating superheated steam. Therefore, this change does not impact the ECCS from performing its design basis function during hot leg recirculation.

Page 3 of 3

Document Control Desk

  • Attachment 2
  • LR-N970256 LCR S97-11 SALEM GENERATING STATION UNIT NOS. 1 AND 2 FACILITY OPERATING LICENSES DPR-70 AND DPR-75 DOCKET NOS. 50-272 AND 50-311 CHANGE TO TECHNICAL SPECIFICATIONS EMERGENCY CORE COOLING SUBSYSTEMS 10CFR50.92 EVALUATION Public Service Electric & Gas (PSE&G) has concluded that the proposed changes to the Salem Generating Station Unit Nos. 1 and 2 Technical Specifications (TS) do not involve a significant hazards consideration. In support of this determination, an evaluation of each of the three standards set forth in 10CFR50.92 is provided below.

REQUESTED CHANGE The requested change to Technical Specification 3.5.2, "ECCS Subsystems - T~g ~ 350°F," consists of deleting Limiting Condition for Operation (LCO) 3.5.2.c.2. This change eliminates the direct flow path from the Residual Heat Removal (RHR) system to the Reactor Coolant System (RCS) hot legs as specified in Limiting Condition for Operation (LCO) 3.5.2.c.2.

PSE&G requests this change to ensure RHR pump operation during all hot leg recirculation configurations assuming worst case single failures that could result in increased flows following a Loss of Coolant Accident (LOCA) during hot leg recirculation.

This reduction in RHR pump flow during hot leg recirculation will reduce the net positive suction head (NPSH) required for the RHR pumps and provide additional margin to ensure that the RHR pumps will have adequate NPSH during hot leg recirculation.

BASIS

1. The proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

The proposed change involves removing the RHR hot leg injection flow path (RH26 valve) during the hot leg recirculation phase of accident mitigation. There are no physical plant modifications being made as a result of the proposed changes and no new accident initiators are created by the proposed changes. This change only involves a system used for ECCS accident mitigation and is consistent with the flow requirement assumptions made in the safety analysis for hot leg recirculation. Therefore, the proposed changes do Page 1 of 3

r-Document Control Desk

  • Attachment 2
  • LR-N970256 LCR S97-ll not involve a significant increase in the probability of an accident previously evaluated.

Removal of the RHR hot leg injection flow path does not impact the ability of the ECCS to mitigate the consequences of an accident but clarifies the flow paths in the ECCS that are required to meet the accident analysis. Operation of one Intermediate Head Safety Injection (IHSI) pump during hot leg recirculation continues to provide adequate core cooling flow such that the hot leg flow directly from the RHR system is not required. Therefore, the proposed change does not involve a significant increase in the consequences of an accident previously evaluated.

2. The proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.

The proposed change to LCO 3.5.2.c.2 does not involve any physical changes to the plant components, systems, or structures. This change does not affect the ability of the Emergency Core Cooling System to meet the flow required in the accident analysis to remove core decay heat without creating superheated steam during hot leg recirculation.

There are no new failure modes introduced as a result of the proposed change since the RH26 valve will remain in the closed position with power to the valve removed during operation in Modes 1 - 3 as required by TS surveillance requirement 4.5.2.a.l.e and will remain in the closed position following a LOCA in Modes 1 - 3. Therefore, the proposed change does not create the possibility of a new or different kind of accident from any previously evaluated.

3. The proposed change does not involve a significant reduction in a margin of safety.

Hot leg recirculation occurs approximately 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br /> into the accident. At this time, the RCS pressure is at equilibrium with the containment pressure, which is conservatively assumed to be at 25.0 psig. At this pressure, the enthalpy of saturated steam is 1160.1 BTU/lbm, and of saturated liquid is 208.52 BTU/lbm. Decay heat generation at this time is 24,540 BTU/sec. Therefore, the required hot leg injection flowrate to prevent superheat is 24,540/(1160.1-208.52)= 25.77 lbm/sec. The flow delivered by one Intermediate Head Safety Injection (IHSI) pump to two hot legs is 76.03 lbm/sec at a backpressure of 25.0 psig. For the break locations considered for long-term transients, nearly all of this flow will enter the vessel and will be Page 2 of 3

e.

Document Control Desk

'Attachment 2

  • LR-N970256 LCR S97-11 available to cool the core. Additional cooling will be provided by simultaneous cold leg injection flow.

Therefore, sufficient injection flow exists to prevent superheat and the change to the hot leg recirculation does not affect the LOCA mass and energy or containment integrity calculation.

With the elimination of the RCS hot leg flow path, the ECCS system will continue to meet the limiting design basis hot leg flow requirement assuming a single failure which can result in operation of a single IHSI pump aligned for hot leg recirculation.

Therefore, the proposed change does not reduce the margin of safety since the accident analysis flow requirements and design basis single failure requirements continue to be met for hot leg recirculation.

CONCLUSION Based on the above, PSE&G has determined that the proposed changes do not involve a significant hazards consideration.

Page 3 of 3

Document Control Desk

,Attachment 3

  • LR-N970256 LCR S97-11 SALEM GENERATING STATION UNIT NOS. 1 AND 2 FACILITY OPERATING LICENSES DPR-70 AND DPR-75 DOCKET NOS. 50-272 AND 50-311 CHANGE TO TECHNICAL SPECIFICATIONS ECCS Subsystems - T0 g ~ 350°F TECHNICAL SPECIFICATION PAGES WITH PROPOSED CHANGES The following Technical Specifications for Facility Operating License No. DPR-70 are affected by this change request:

Technical Specification Page 3/4.5.2 3/4 5-3 The following Technical Specifications for Facility Operating License No. DPR-75 are affected by this change request:

Technical Specification Page 3/4.5.2 3/4 5-3 Page 1 of 1

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