LR-N15-0147, License Renewal Commitment Implementation

License Renewal Commitment Implementation

ML15203A072
Person / Time
Site:	Hope Creek
Issue date:	07/22/2015
From:	Davison P Public Service Enterprise Group
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
FOL 2.C.(27), LR-N15-0147
Download: ML15203A072 (8)

Text

PSEG Nuclear LLC P.O. Box 236, Hancocks Bridge, NJ 08038-0236 FOL 2.C. (27)

LR-N15-0147 JUL 2 2 2015 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Hope Creek Generating Station Renewed Facility Operating License No. NPF-57 NRC Docket No. 50-354

Subject:

License Renewal Commitment Implementation

References:

(1) LR-N12-0212, "License Renewal Commitment Implementation,"

dated July 19, 2012 The Renewed Operating License No. NPF-57 for Hope Creek Generating Station (HCGS) was issued on July 20, 2011. The renewed license included several license conditions related to the ASME Section XI, Subsection IWE aging management program and, in particular, to the Hope Creek drywell air gap drains. In accordance with License Condition 2.C. (27) c, this letter transmits a report summarizing the results of the ultrasonic thickness (UT) measurements taken during Refueling Outage 19.

There are no regulatory commitments contained in this letter.

If you have any questions or require additional information, please do not hesitate to contact Mr. Philip J. Duca at 856-339-1640.

Sincerely,

\.CU Paul J. Davison Site Vice President - Hope Creek pj d '

Attachment - Hope Creek Generating Station License Renewal Commitment Implementation 90-Day Report for Refueling Outage 19

NRG Document Control Desk LR-N15 -0147 Page 2 cc: Mr. D. Dorman, Administrator, Region I Nuclear Regulatory Commission Ms. Carlene Parker - Project Manager Hope Creek USNRC Mr. Justin Hawkins - NRG Senior Resident Inspector - Hope Creek (X24)

Mr. Thomas MacEwen - Hope Creek Commitment Coordinator (H02)

Mr. Lee Marabella - Corporate Commitment Coordinator (N21)

Mr. P. Mulligan, Manager IV Bureau of Nuclear Engineering New Jersey Department of Environmental Protection PO Box 420 Trenton, New Jersey 08625

LR-N15-0147 Attachment Hope Creek Generating Station License Renewal Commitment Implementation 90-Day Report for Refueling Outage 19

LR-N15-0147 Attachment Page 1 of 5 Hope Creek Generating Station License Renewal Commitment Implementation 90-Day Report for Refueling Outage 19

Background:

Renewed Operating License No. NPF-57 for Hope Creek Generating Station was issued on July 20, 2011. The renewed license contains several license conditions related to License Renewal and, in particular, to the Hope Creek drywell air gap drains.

Some portions of these License Conditions were included in the Refueling Outage (RF) 17 scope and were worked during the outage that began on April 13, 2012, and ended on May 9, 2012. Continued investigations and changes were included in RF 18 scope and were worked during the outage that began on October 11, 2013, and ended November 10, 2013. Monitoring of air gap leakage and performance of drywell shell UT thickness measurements were included in the RF 19 scope and were worked during the outage that began on April 10, 2015, and ended May 13, 2015.

The relevant license conditions are contained in Section 2.C of the renewed license.

Specifically, Section 2.C.(27) delineates those activities required to be performed following the establishment of drainage capability from the drywell air gap (that is, following completion of license condition 2.C.(26)) and reads as follows:

(27) After drainage has been established from the bottom of the air gap in all four quadrants, the licensee will:

a. Submit a report to the NRG staff in accordance with 10 CFR 50.4 describing the final drain line configuration and summarizing the testing results that demonstrate drainage has been established for all four quadrants.

b. Monitor penetration sleeve J13 daily for water leakage when the reactor cavity is flooded up. In addition, perform a walk-down of the torus room to detect any leakage from other drywell penetrations. These actions shall continue until corrective actions are taken to prevent leakage through J13 or through the four air gap drains.

c. Perform UT measurements of the drywell shell between elevation 86'-11" (floor of the drywell concrete) and elevation 93'-0" (bottom of penetration J13) below penetration J13 area during the next three refueling outages. In addition, UT measurements shall be performed around the full 360 degree circumference of the drywell between elevations 86'-11" and 88'-0" (underside of the torus down comer vent piping penetrations). The results of the UT measurements will be used to identify drywell surfaces requiring augmented inspections in accordance with IWE requirements for the period of extended operation, establish a corrosion rate, and demonstrate that the effects of aging will be adequately managed such that the drywell can perform its intended function until April 11, 2046. Within 90 days of completion of each refueling outage, submit a report to the NRG staff in accordance with 10 CFR

LR-N15-0147 Attachment Page 2 of 5 Hope Creek Generating Station License Renewal Commitment Implementation 90-Day Report for Refueling Outage 19 50.4 summarizing the results from the UT measurements and if appropriate, corrective action.

Summary of Commitment Implementation:

The action required by License Condition 2.C. (27) a. was completed and the results submitted to the NRC in PSEG Letter No. LR-N12-0212 dated July 19, 2012. In accordance with License Condition 2.C. (27), this report discusses the actions taken by PSEG during Hope Creek Refueling Outage 19 (RF19) to satisfy license condition 2.C.

(27) b. and 2.C. (27) c., above. The specific license conditions addressed and/or resolved during RF19 are as follows:

A Monitoring of J13 Penetration Sleeve (License Condition 2.C. (27) b.)

During RF19, the J13 penetration sleeve was monitored daily for leakage while the reactor cavity was flooded up (April 13, 2015 through April 30, 2015).

Further, the penetrations adjacent to penetration J13 (J19, J14, J29, J24, and J37, specified here as the "J13 penetration group") and the air gap drains were monitored daily for water leakage. In addition, a full walk-down of the torus room was performed to confirm there was no leakage from any other penetrations.

Walk-downs were performed daily while the reactor cavity was flooded by Operations in accordance with Operating Procedure HC.OP-IO. ZZ-0005, COLD SHUTDOWN TO REFUELING, and by Engineering. During the walk-downs following reactor cavity flood-up and continuing until reactor cavity drain down, water was observed at the 225 degree azimuth from the J13 penetration group (specifically the J19 penetration) as well as the excavated access tunnel located at 250 degree azimuth (credited air gap drain).

On April 17, 2015, leakage was identified from penetration sleeve J19 at a leak rate of approximately 42 drops per minute. Note that penetrations J13 and J19 are at the same elevation and are separated by approximately 25 inches. No water was noted leaking from any other areas within the torus room. The leak rate from the J19 penetration remained at or around 42 drops per minute through April 20, 2015. On April 20, 2015 leakage was also observed coming out of the excavated access tunnel at 250 degree azimuth. The leakage from the 250 degree azimuth tunnel was estimated to be approximately 10 drops per minute.

On April 21, 2015 the 250 degree azimuth tunnel leakage remained at approximately 10 drops per minute while the penetration J19 leakage dropped to approximately 20 drops per minute. On April 22, 2015 the leakage from the 250 degree azimuth tunnel ceased and the leakage from the penetration J19 diminished to approximately 2 drops per minute. The leakage form the 250 degree azimuth tunnel never returned and the penetration J19 leakage continued

LR-N15-0147 Attachment Page 3 of 5 Hope Creek Generating Station License Renewal Commitment Implementation 90-Day Report for Refueling Outage 19 to diminish over the next several days. The last leakage was recorded on April 25, 2015 from the penetration J19 at a rate of approximately 1 drop per minute.

It is likely that the leakage observed April 22 through 25, 2015 was residual leakage. Note that the cavity remained flooded through April 30, 2015. The chart below represents a comparison of the RF19 leakage to that of the RF18 leakage where the X-axis represents days following flood up and the Y-axis represents cumulative gallons leaked.

18.00 16.00 14.00 12.00 10.00 too 6.00 RF19 4.00 2.00 0,00 1 2 3 4 s 6 7 8 9 10 11 12 13 14 15 16 17 Note that the time from flood up to first observation of leakage during RF19 was four days versus two days during RF18. In addition, the leakage during RF19 lasted only five days versus fourteen days during RF18. The RF19 total leakage was less than 25% of that collected during RF18. The characteristic deltas between the observed leakage from RF18 to RF19 will be taken into consideration when developing leak investigation efforts for RF20.

From the monitoring conducted during RF19 it can be concluded that the source of the leakage has not degraded from RF18 to RF19. No leakage was observed from any other air gap penetration sleeves and there was no sign of leakage from the end of the other three drywell air gap drains (at 80, 160 and 340 degree azimuths) or from the excavated tunnels at 290, 155 and 115 degree azimuths.

The Reactor Cavity to Drywell Seal Rupture Drain Alarm (HC.OP-AR.ZZ-0024, Alarm point 03837) did not actuate. All leakage stopped before draining of the reactor cavity.

LR-N15-0147 Attachment Page 4 of 5 Hope Creek Generating Station License Renewal Commitment Implementation 90-Day Report for Refueling Outage 19 B. UT Measurements (License Condition 2.C. (27) c. )

The Ultrasonic Thickness (UT) measurements prescribed by license condition 2.C. (27) c. were performed during RF19. Based on the consistency of the UT measurements with those taken in previous outages, PSEG has concluded that no corrosion is occurring on the drywell shell.

UT measurements were performed on the drywell shell at the 225 degree azimuth between 86'-11" and 93'-0" elevation (below the J13 penetration group).

The lowest UT measurements occurred on a plate below the J13 penetration group and measured 1.475" in RF16, 1.470" in RF17, 1.477" in RF18, and, 1.490" in RF19. Note that these readings were not at the same measurement point but were the lowest of all recorded readings taken during the respective outages.

Comparing the lowest reading of 1.470" (from RF17) to the analysis limit of 1.4375" proves that at least 32.5 mils thickness margin remains. Further, the consistency of the thickness measurements proves that no corrosion to the drywell shell is occurring below the J13 penetration group. It should be noted that during development of the Hope Creek license renewal application, PSEG concluded that the cause of the lower readings on this plate were due to the plate's construction tolerances being at the lower end, but acceptable for use.

UT measurements were also performed for the full circumference of the drywell shell between elevations 86'-11" and 88'-0". The bottom of the drywell air gap is on the outside of the drywell shell between these elevations. The lowest UT measurements at the bottom of the drywell were 1.480" in RF16, 1. 477" in RF17, 1.471" in RF18, and 1.475" in RF19. Note that these readings were not at the same measurement point but were the lowest of all recorded readings taken during the respective outages. Comparing the lowest reading of 1.471" (from RF18) to the analysis limit of 1.4375" shows that 33.5 mils thickness margin remains. Based on the consistency of these UT measurements, PSEG has concluded that no corrosion is occurring in the drywell shell at the bottom of the drywell air gap. Nevertheless, even if a very conservative corrosion rate of 6 mils per cycle were to be assumed, the analysis limit of 1.4375 would not be reached for at least 5 cycles. The UT measurements will be taken again during the RF20 outage to confirm that no corrosion is occurring in the drywell shell.

The UT measurement activities required to be completed during RF19 by license condition 2.C. (27) c. were completed as described above. License condition 2.C. (27) c. requires these UT measurement activities for the three refueling outages following establishment of drainage capability from the bottom of the drywell air gap. RF19 is the second of these outages. Therefore, these UT measurement activities will be performed during the next outage. The results of

LR-N15-0147 Attachment Page 5 of 5 Hope Creek Generating Station License Renewal Commitment Implementation 90-Day Report for Refueling Outage 19 the RF20 UT measurement activities will be compared to the previous UT measurement results to determine if any corrosion is occurring and to determine a corrosion rate if corrosion is identified. Should a significant corrosion rate be detected, the condition will be entered into the corrective action process for resolution.

C. Corrective Actions The reactor cavity leakage is currently an ongoing investigation. Additional investigatory actions will be defined for RF20 since the leakage only occurs while the reactor cavity is flooded. While the reactor cavity leakage continues to exist, the actions prescribed by License Condition 2.C. (27) and UFSAR Section A.5, Commitment No 28; Sub-commitment 10 (Pages A-70 & 71) will be performed.

There were no additional corrective actions as a result of the activities in RF19.

==

Conclusion:==

Activities associated with the Hope Creek renewed operating license condition 2.C. (27) that were required to be completed during the RF19 refueling outage were completed.

License Condition 2.C. (27) a. was satisfied through submittal of PSEG Letter No. LR N12-0212 on July 19, 2012. License conditions 2.C. (27) b. and 2.C. (27) c were satisfied during RF18 as documented in LR-N14-0029, and for RF19 as discussed above. This report satisfies the reporting requirements of 2.C. (27) c. The results of the UT measurements demonstrate there are currently no drywell surfaces requiring augmented inspections in accordance with IWE requirements.