05000389/LER-2018-001-01, Pressurizer Instrument Nozzle Leak Due to Primary Water Stress Corrosion Cracking
| ML18351A242 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 12/17/2018 |
| From: | Deboer D Florida Power & Light Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-2018-238 LER 2018-001-01 | |
| Download: ML18351A242 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) |
| 3892018001R01 - NRC Website | |
text
U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 Re:
St. Lucie Unit 2 Docket No. 50-389 Reportable Event: 2018-001-01 Date of Event: September 11, 2018 DEC 1 7 2018 Pressurizer Instrument Nozzle Leak Due to Primary Water Stress Corrosion Cracking L-2018-238 10 CFR 50.73 Revision 1 to Licensee Event Report 2018-001 is being submitted pursuant to the requirements of 10 CFR 50.73 to provide notification of the subject event.
Respectfully, Daniel DeBoer Site Director St. Lucie Plant DD/ KWF Attachment cc:
St. Lucie NRC Senior Resident Inspector St. Lucie NRC Program Manager Florida Power & Light Company 6501 S. Ocean Drive, Jensen Beach, FL 34957
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2018)
Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />.
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Reported lessons learned are incorporated into the licensing process and fed back to industry.
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LICENSEE EVENT REPORT (LER)
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- 3. PAGE St. Lucie Unit 2 05000389 1 OF 3
- 4. TITLE Pressurizer Instrument Nozzle Leak Due to Primary Water Stress Corrosion Cracking
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED YEAR I SEQUENTIAL I REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR NUMBER NO.
MONTH DAY YEAR n/a 05000 FACILITY NAME DOCKET NUMBER 9
11 2018 2018 -
001 1
12 17 2018 n/a 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
D 20.2201 (b)
D 20.2203(a)(3)(i)
~ 50.73(a)(2)(ii)(A)
D 50. 73(a)(2)(viii)(A)
D 20.2201 (d)
D 20.2203(a)(3)(ii)
D 50. 73(a)(2)(ii)(B)
D 50. 73(a)(2)(viii)(B) 0 D 20.2203(a)(1)
D 20.2203(a)(4l D 50.73(a)(2)(iii)
D 50. 73(a)(2)(ix)(A)
D 20.2203(a)(2)(i)
D 50.36(c)(1 )(i)(A)
D 50.73(a)(2)(iv)(A)
D 50.73(a)(2)(x)
- 10. POWER LEVEL D 20.2203(a)(2)(ii)
D 50.36(c)(1 )(ii)(A)
D 50.73(a)(2)(v)(A)
D 73.71 (a)(4)
D 20.2203(a)(2)(iii)
D 50.36(c)(2)
D 50.73(a)(2)(v)(B)
D 73.71 (a)(5)
D 20.2203(a)(2)(iv)
D 50.46(a)(3)(ii)
D 50.73(a)(2)(v)(C)
D 73.77(a)(1) 0 D 20.2203(a)(2)(v)
D 50. 73(a)(2)(i)(A)
D 50.73(a)(2)(v)(D)
D 73.77(a)(2)(i)
D 20.2203(a)(2)(vi)
~ 50. 73(a)(2)(i)(B)
D 50.73(a)(2)(vii)
D 73.77(a)(2)(ii)
D 50.73(a)(2)(i)(C)
D OTHER Specify in Abstract below or in
Safety Significance
The discovered flaw had low safety significance for the following reasons:
The leak was small enough that it was not quantifiable in the daily RCS leak rate calculations and had not increased to the point where it was visible through the pressurizer insulation.
The flaw was not circumferential.
The hot leg and pressurizer penetration ISi augmented inspection frequencies provide reasonable assurance that any as-found flaw is detected well before it could develop into a significant condition.
The leak did not adversely impact the ability of the plant to shutdown, maintain shutdown conditions, nor mitigate any postulated accident conditions.
Additionally, all remaining Alloy 600 locations are at lower temperature operating conditions and are managed by the Alloy 600 Management Program and inspected within the augmented ISi inspection program. Therefore, this event had no impact on the health and safety of the public.
Corrective Action
- 1. The flawed pressurizer nozzle attachment weld pad was replaced with material resistant to PWSCC during the St. Lucie Unit 2 refueling outage. This was the last remaining small bore instrument piping on the pressurizer with this Alloy 600 configuration.
Failed Components Identified Pressurizer instrument nozzle 016-02B Alloy 600/82 Weld Pad
Similar Events
There were no other PWSCC related events at St. Lucie during the past three years. Page 3 of 3