ML20247C248

License Change Application ECR 98-00499 for Amends to Licenses DPR-44 & DPR-56,revising TS to Delete Requirements for Functional Testing of SRVs During Each Unit Startup

ML20247C248
Person / Time
Site:	Peach Bottom
Issue date:	05/01/1998
From:	Geoffrey Edwards PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20247C254	List: ML20247C248 ML20247C261
References
NUDOCS 9805130070
Download: ML20247C248 (12)

Text

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ttztlon Cupport DeptrimInt 10 CFR 50.90

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y PECO NUCLEAR ecco cee,2v cemee,x A Unit of PECO Energy wayrIP 1 7 1 May 1,1998 Docket Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 1

U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555

Subject:

Peach Bottom Atomic Power Station, Units 2 and 3

[ License Change Application ECR 98-00499 and Submittal j of Relief Request 01A-VRR-1

Dear Sir / Madam:

PECO Energy Company (PECO Energy) hereby submits License Change Application ECR 98-00499, in accordance with 10 CFR 50.90, requesting a change to the Peach Bottom Atomic Fower Station (PBAPS), Units 2 and 3 Facility Operating Licenses. This proposed change will revise the Technical Specifications (TS) to delete requirements for the functional testing of the Safety Relief Valves (SRVs) during each unit startup.  !

Also included for your review and approval is Relief Request 01A-VRR-1 associated with the third, ten-year-interval, inservice Testing (IST) Program for PBAPE, Units 2 and 3. This relief request seeks relief from the ASME OM Code which requires quarterly stroking and manually actuating the Automatic Depressurization System (ADS) SRVs.

Information supporting this request is contained in Attachment 1 to this letter, and the marked up pages showing the prooosed changes to the PBAPS, Units 2 and 3 TS are contained in Attachment 2. Relief Request 01 A-VRR-1 is contained in Attachment 3.

We request that this amendment to the PBAPS, Units 2 and 3 TS be approved by September 21,1998 for implementation during the upcoming PBAPS, Unit 2 outage currently scheduled to begin in October 1998, and for the PBAPS, Unit 3 outage currently scheduled to begin in October,1999.

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, May 1, 'i998 Page 2 l If you have any questions, please do not hesitate to contact us.

Ve truly yours, .

A es &

Garrett D, Edwards l Director - Licensing

Enclosures:

Affidavit, Attachment 1, Attachment 2, Attachment 3 1

cc: H. J. Miller, Administrator, Region I, USNRC A. C. McMurtray, USNRC Senior Resident inspector, PBAPS R. R. Janati, Commonwealth of Penn'aylvania l

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COMMONWEALTH OF PENNSYLVANIA:

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COUNTY OF YORK  :

J. Doering, being first duly sworn, deposes and says:  !

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That he is Vice President of PECO Energy Company; the Applicant herein; that he has read the attached License Change' Application ECR 98-00499, for Peach Bottom Facility Operating Licenses DPR-44 and DPR-56, and knows the contents thereof; and that the statements and coatters set forth therein are true and correct to the  !

best of his knowledge, information'and belief. l

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Vice President / l Subscribed arid sworn to before me this 30th day of April 1998.

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Notary Public r

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ATTACHMENT 1 PEACH BOTTOM ATOMIC POWER STATION UNITS 2 AND 3 Docket Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 LICENSE CHANGE APPLICATION ECR 98-00499

" Safety Relief Valve Surveillance Testing" Supporting Information - 7 Pages

Docket Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 Introduction PECO Energy Company, Licensee under Facility Operating Licenses DPR-44 and DPR-56 for the Peach Bottom Atomic Power Station (PBAPS), Units 2 and 3, requests that the Technical Specifications (TS) contained in Appendix A to the Operating License be amended to delete requirements for functional testing of the Safety Relief Valves (SRVs) during each unit startup. The TS and Bases pages showing the proposed changes are contained in Attachment 2. This License Change Application provides a discussion and description of the proposed changes, a safety assessment of the proposed changes, information supporting a finding of No Significant Hazards Consideration, and information supporting an Environmental Assessment.

Discussion and Description of the Proposed Chanae The proposed changes are associated with surveillance testing that requires manually actuating every safety relief valve (SRV) during each unit startup from a refueling outage. The proposed changes provide an alternate method of testing the SRVs during shutdown conditions rather than during unit startup as is currently done. This approach is expected to reduce the probability of valve leakage, thereby reducing the possibility of a plant shutdown or an inadvertent valve actuation resulting in a plant transient.

Attachment 2 contains the TS and Bases pages showing the proposed changes. A summary of the proposed changes is as follows:

1. The current TS SR 3.4.3.2 requires manual testing of each SRV. This Surveillance .

Requirement (SR) states the following: " Verify each required SRV opens when i manually actuated." This SR also includes a note which states that this SR is not required to be performed until 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after reactor steam pressure and flow are adequate to perform the test.

PECO Energy proposes that this SR be revised to verify that each required SRV actuator strokes when manually actuated in the depressur zation mode. This SR will  ;

state the following: " Verify each required SRV actuator strokes when manually I actuated in the depressurization mode." Additionally, PECO Energy proposes that the current SR note be deleted.

2. The current TS SR 3.5.1.12 requires manual testing of each ADS. This SR states the following: " Verify each ADS valve opens when manually actuated." This SR also includes a note which states that this SR is not required to be performed until 12 l hours after reactor steam pressure and flow are adequate to perform the test. j PECO Energy proposes that this SR be revised to verify that each ADS valve I actuator strokes when manually actuated in the depressurization mode. This SR will state the following: " Verify each ADS valve actuator strokes when manually actuated ,

in the depressurization mode." Additionally, PECO Energy proposes that the note be j deleted.

the PBAPS, Units 2 and 3 Technical Specification Bases 3.4.3.2 arid Additionally, 3.5.1.12 will be revised to reflect the methodology of verifying actuator stroke.  ;

PECO Energy is requesting approval of the proposed TS and Bases pages contalned in 1

Dockst Nos. 50-277 i 50-278 i License Nos. DPR-44 ,

DPR-56 Attachnient 2 for both units.

Safety Assessment The PBAPS, Units 2 and 3 SRVs are Target Rock, 3-Stage, Model 67F design (Diagram A). The SRVs are dual function valves capable of. being independently opened in either the safety or the depressurization mode of operation. The purpose of the safety mode is to protect the reactor vessel from overpressurization. During this mode, the valves are automatically opened by a set pressure. The purpose of the depressurization mode is to reduce reactor pressure during a "small break" LOCA (Automatic Depressurization System (ADS) function) so that a low pressure Emergency Core Cooling System (ECCS) can provide makeup water to the vessel and flood the core. During this mode, the valves are. manually or automatically opened by a i pneumatic actuator. I 1

PBAPS is designed with eleven (11) SRVs distributed between the four main steam lines. These vaices are designed to protect the reactor vessel by providing pressure relief during high pressure transients. - There are three different setpoints; 1135 psig, t

1145 psig, and 1155 psig. Five (5) of the SRVs also perform the ADS function. The ADS function operates in the depressurization mode. The SRVs are installed so that i each valve discharge is piped through its own discharge line to a point below the l minimum water level in the suppression pool.

The current TS SR 3.4.3.2 requires that each SRV be opened when manually actuated.

Additionally, current TS SR 3.5.1.12 requires that each ADS valve be opened and manually actuated. As discussed in the Note associated with these TS SRs, this test is not required to be performed until 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after reactor steam pressure and flow are adequate to perform this test, in addition to current testing required by TS SR 3.4.3.2 and SR 3.5.1.12 that manually actuates every safety relief valve (SRV) during each unit startup from a refueling outage, the following tests verify the entire SRV assembly functions adequately: 1

. A. ASME OM Code - 1990 Edition, Appendix 1, Setpoint/ Leakage Testing As required by ASME OM Code - 1990 Edition, Appendix 1, during each refueling outage, which occurs on a 24 month frequency, approximately 50% of the SRVs (currently the entire valve assembly) are removed and shipped to an offsite testing facility for "as-found" testing. Testing is performed.in accordance with the offsite testing facility procedure. This testing includes visual inspection, leakage testing, valve body leakage testing, delay time testing, and set pressure testing (i.e., TS setpoint hmits), all of which are performed prior to any maintenance on the valve. The seat leakage test is. performed at a steam pressure of approximately 1040 psig and set pressure testing is performed at the Technical Specification lift setpoints.

Following the "as-found" testing, the SRVs undergo a dimensional inspection if valve refurbishment is required. This refurbishment is performed by the valve supplier, currently Target Rock Corporation.

If valve refurbishment is required, post-maintenance testing is performed. This testing includes visual inspection, leakage testing, valve body leakage testing, 2

.. l Docktt Nos. 50-277 50-278 License Nos. DPR-44  !

DPR-56 delay time' testing, and set pressure testing (i.e., TS setpoint limits). The final seat leakage test is performed at approximately 1040 psig. Upon successful test completion, the valve receives written certification from the lab and is returned to PBAPS for reinstallation. To receive certification, the valve must have zero seat leakage and meet the acceptance criteria for set pressure. These tests satisfy the requirements of the ASME OM Code - 1990 Edition, Appendix 1, and are also used to satisfy the requirements of TS SR 3.4.3.1 for lift setpoint pressure verification. The test satisfies the verification of the safety mode function.

B. ADS Logic System Functional Test Per TS SR 3.3.5.1.5, a logic system functional test is performed every 24 months which demonstrates the operability of the required initiation logic for the ADS.

1 C. ADS Simulated Automatic Actuation Test I l

Per Technical Specification SR 3.5.1.11, testing is performed each cycle that verifies that individual channel calibrations and functional tests of the ADS have been satisfactorily completed within 24 months. The satisfactory completion of all tests listed in this procedure satisfies the simulated automatic actuation testing requirement of Technical Specification SR 3.5.1.11.

D. ADS Supply Instrument Gas / Accumulator Leakage Test The ADS supply instrument gas / accumulator leakage is tested every 24 months in accordance with the PBAPS Inservice Testing (IST) Program, and each time maintenance is performed on the ADS valve, to ensure that there will be sufficient pneumatic pressure to actuate the valve.

in addition to the above described tests which are currently performed on the SRVs, PECO Energy proposes that the current testing contained in TS SR 3.4.3.2 and 3.5.1.12 be revised to energize the solenoid, stroke the actuator, and verify second stage disc movement of all 11 SRVs in the depressurization mode.

The combined tests (A through D) discussed above, and the proposed test contained in TS SR 3.4.3.2 and 3.5.1.12, will verify that' the entire SRV assembly functions adequately.

~ As a result of deleting the requirement for functional testing of the SRVs during each unit startup and replacing these requirements with the proposed tests contained TS SR  ;

3.4.3.2 and 3.5.1.12, the only change in the frequency of testing of the SRV l components is that the main valve disc of the SRVs will be tested every two cycles (approximately four years) as compared to the current one cycle (approximately two years) frequency. As described above, the lift test of the main valve disc is currently performed at an offsite facility. A review of offsite testing data for the years 1987 through 1998 was performed for the PBAPS, Units 2 and 3 SRVs. Since the design of the SRVs is to ensure operation of the overpressurization protection and the ADS function is to reduce reactor pressure during a small break LOCA, the review consisted of looking for any failures of the main valve disc to stroke open during setpoint actuation. This review consisted of reviccing "as-found" test data since any failures following a rebuild would be found during the final certification testing. Based on a review of as-found data, it was concluded that there were no reported cases of the main 3

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Docket Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 disc falling to open during setpoint pressure testing. Therefore, deleting the requirement for functional testing of the SRVs during each unit startup is not expected to negatively impact these test results.

There has been one occurrence of an SRV second stage disc leakage that required a j plant shutdown which is suspected to have resulted from functional testing of the SRVs 1 during startup. This event occurred in November,1997 on PBAPS, Unit 3 due to second stage seat leakage caused by steam cutting of the seat and disc area. After manual actuation of the SRV at approximately 150 psig, tailaipe temperature plots indicated an abnormal increase in temperature. Althoug 1 it is probable that corrosion / debris on the second stage disc and seat area was the most likely cause, it was concluded that the primary contributor to second stage seat leakage was increased as a result of the functional test of the SRV. As a result of the increased tailpipe temperature, a plant shutdown was initiated to remove the SRV from service. Gross second stage leakage can lead to an inadvertent lift of an SRV as described in the General Electric Company Service Information Letter (SIL) No.196, Category 1,

" Summary of Recommendations for Target Rock Main Steam Safety / Relief Valves."

As discussed in the Bases Section 3.4.3.2, the purpose of SR 3.4.3.2 is to verify that, mechanically, the valves are functioning properly and no blockage exists in the valve discharge open to relieve lines. Thispressure excess requirement is lift when the applicable setpoint isonly to their exceeded capability safety mode). (to mechan However, manual actuation can only be performed using the pneumatic actuation system (i.e., the depressurization mode) at pressures greater than or equal to 150 psig.

Additionally, the manual actuation test at pressures greater than or equal to 150 psig does not assure SRV operability in the safety mode since the safety mode TS setpoint pressures are 1135 psig,1145 psig, and 1155 psig.

As discussed in the Bases Section 3.5.1.12, the purpose of SR 3.5.1.12 is to perform a manual actuation of each ADS valve to verify that the valve and solenoid are functioning properly and that no blockage exists in the SRV discharge line. As discussed previously, additional testing is performed to demonstrate the proper functioning of the solenoid valve.

With regard to verifying that no blockage exists in the SRV discharge line, PBAPS has  !

Foreign Materials Exclusion (FME) Program controls in place on all openings when i SRVs are removed and reinstalled. The horizontal orientation of the SRV discharge line mating surfaces provides reasonable assurance that no obstructions will be ,

admitted into the SRV discharge tailpipe. The piping size ranges from 10 inches to 12 l inches, therefore, a piping restriction would have to be relatively large, in addition, FME Procedures are utilized before removing and shipping the SRVs. These controls provide reasonable assurance that no blockage will be admitted into the SRV discharge line. Additionally, PBAPS has not experienced a surveillance failure related to line ,

blockage as a result of removing the SRVs each refueling cycle since plant startup.

Reducing the challenges to the SRVs is a recommendation of NUREG-0737, item II.

K.3.16," Reduction of Challenges and Failures of Relief Valves." The recommendation is based on a stuck open SRV being a possible cause of a LOCA. This submittal is l consistent with that recommendation.

Information Supportina a Findina of No Significant Hazards Consideration 4

Dockst Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 We have concluded that the proposed changes to the PBAPS, Units 2 and 3 TS do not involve a Significant Hazards Consideration. In support of this determination, an evaluation of each of the three (3) standards set forth in 10 CFR 50.92 is provided below.

1. The proposed TS chances do not involve a significant increase in the probability or consequences of an accident previously evaluated.

1 The proposed Technical Specification changes to the re,quirement for functional testing of the SRVs during each unit startup will not significantly increase the probability or consequences of an accident previously evaluated. Elimination of ,

the functional test will not prevent the SRVs from performing their intended i safety function. The proposed change to delete the SRV functional test at power should delete a potential initiator of SRV leakage. The remaining testing and inspections will continue to adequately demonstrate the operability of the SRVs for both the safety and depressurization modes.

As a result of deleting the requirement for functional testing of the SRVs during each unit startup and replacing these requirements with the proposed tests contained TS SR 3.4.3.2 and 3.5.1.12, the only change in the frequency of testing of the SRV components is that the main valve disc of the SRVs will be tested every two cycles (approximately four years) as compared to the current one cycle (approximately two years) frequency. As described above, the lift test of the main valve disc is currently performed at an offsite facility. A review of offsite testing data for the years 1987 through 1998 was performed for the PBAPS, Units 2 and 3 SRVs. Since the design of the SRVs is to ensure operation of the overpressurization protection and the ADS function is to reduce reactor pressure during a small break LOCA, the review consisted of lookin any failures of the main valve disc to stroke open during setpointThis actuation.g for review consisted of reviewing "as-found" test data since any failures following a rebuild would be found during the final certification testing. Based on a review of  :

as-found data, it was concluded that there were no reported cases of the main disc failing to open during setpoint pressure testing. Therefore, deleting the requirement for functional testing of the SRVs during each unit startup is not expected to negatively impact these test results.

Therefore, eliminating the functional test is not expected to negatively impact these test results or involve a significant increase in the probability of an accident previously evaluated.

As occussed in the PBAPS, Units 2 and 3 Updated Final Safety Analyses Report (UFSAR), analyzed events resulting in a nuclear system pressure increase, such as MSIV closure, generator load rejection, turbine trip, failure of the turbine bypass valves to open, and loss of main condenser vacuum, take credit for the SRVs opening to mitigate the consequences of these events. The proposed changes will not increase the consequences of these events, since a series of remaining tests will ensure all SRV components will function. The SRVs

, will therefore be capable of performing their design functions.

SRV second stage valve leakage can be increased as a result of corrosion / debris introduced on the seating area surface. Second stage leakage, 5

Dockst Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 if allowed to continually increase, will eventually start to depressurize the volume above the SRV main valve piston to the extent that sufficient differential pressure will lift the main valve disc. Reactor vessel coolant inventory decrease c ue to an inadvertent opening of a Safety Relief Valve is an abnormal operating transient event. This event can be a precursor to fuel failure due to gradual loss of coolant, and the mitigation is similar to the small break LOCA. Under the proposed change, it is expected that the probability of SRV leakage 5.0 decrease, thus the probability of occurrences of a inadvertent SRV actuation is reduced, therefore reducing the probability or consequences of an accident previously evaluated.

2. The proposed TS chanaes do not create the possibility of a new or different kind . '

of accident from any accident previousiv evaluated.

The SRVs will not be operated or tested in a manner contrary to their design. As a result, no new mode of operation is introduced. Therefore, the revised testing will not create a new failure mode of the SRVs which could create the possibility of a new or different kind of accident from any previously evaluated. Since other tests, taken together, confirm the entire SRV assembly functions adequately, this proposed change is justified. The proposed change to delete the SRV functional test at power will not impact the ability of the SRV to open and provide their intended safety function.

3. The orooosed TS chanaes do not involve a significant reduction in a marain of-safety.

By removing the Technical Specification requirements to perform the in-situ functional testing during startup, the probability of inadvertently opening of a SRV should be reduced through the elimination of a potential initiator of SRV second stage disc leakage and subsequent erosion. This Technical Specification change will aid in decreasing SRV leakage and improve SRV reliability at power operations. Eliminating the SRV in-situ functional test during startup will increase the margin of safety during operations, transients, or accidents.

Remaining surveillance testing and inspections assure each component j necessary for successful opening of the SRV function properly as designed.  !

Removal of the functional test will not negatively impact the Technical Specifications lift setpoints of the SRVs necessary for the function of the safety mode. The functional test does not completely test the safety mode of the SRV '

which is based on the Technical Specifications lift setpoints.  ;

I ' Offsite testing at operating steam pressure ensures the operability of the SRV pilot, second stage, and main valve function. The valves are refurbished and post maintenance testing is performed at a steam pressure of 1040 psig. Upon successful test completion, the valve receives written certification from the lab and is returned to PBAPS for reinstallation. To receive certification, the valve must have zero main seat leakage and meet the acceptance criteria for setpoint pressure. These tests satisfy the requirements of the PBAPS IST Program and TS. The tests contained in the proposed TS SR 3.4.3.2 and 3.5.1.12 will verify the operation of the solenoid and second stage disc movement of all 11 SRVs in the depressurization mode.  !

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Docket Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 the remaining segments of the SRV tests verify the ability of the SRV logic. In summary, this change will not involve a significant reduction in the margin of safety, because of the reduction in SRV degradation, and the remaining tests confirm the valves will function properly when required.

l Information Supportina an Environmental Assessment An environmental assessment is not required for the proposed changes since the proposed changes conform to the criteria for " actions eligible for catepacal exclusion" as specified in 10 CFR 51.22(c)(9). The proposed changes will have no impact on the environment. The proposed changes do not involve a significant hazards consideration as discussed in the preceding section. The proposed changes do not involve a significant change in the types or significant increase in the amounts of any effluents that may be released offsite. In addition, the proposed changes do not involve a significant increase in individual or cumulative occupational radiation exposure.

Conclusios We have concluded that the proposed changes to the PBAPS, Units 2 and 3 TS do not involve a Significant Hazards Consideration.

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