05000458/LER-2018-004, Unanalyzed Condition Due to Inadequate Protection from Tornado Generated Missiles

Unanalyzed Condition Due to Inadequate Protection from Tornado Generated Missiles

ML18184A439
Person / Time
Site:	River Bend
Issue date:	07/03/2018
From:	Maguire W Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RBG-47880 LER 2018-004-00
Download: ML18184A439 (5)

LER-2018-004, Unanalyzed Condition Due to Inadequate Protection from Tornado Generated Missiles

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(ix)(A) 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)(8) 10 CFR 50.73(a)(2)(v), Loss of Safety Function
4582018004R00 - NRC Website

text

--- Entergx RBG-47880 July 3,2018 Attn: Document Control Desk U.S. Nuclear Regulatory Commission 11555 Rockville Pike Rockville, MD 20852-2738

Subject:

Dear Sir or Madam:

Licensee Event Report 50-458 I 2018-004-00 River Bend Station, Unit 1 Docket No. 50-458 License No. NPF-47 Entergy Operations, Inc.

River Bend Station 5485 U.S. Highway 61 N St. Francisville, LA 70n5 Tel 225*381-4374 William F. Maguire Site Vice President In accordance with 10 CFR 50.73, enclosed is the subject Licensee Event Report. This document contains no commitments. If you have any questions, please contact Mr. Tim Schenk at 225-381-4177.

Sincerely, WFM/twf Enclosure cc:

(with Enclosure)

U.S. Nuclear Regulatory Commission Attn: Ms. Lisa M. Regner, Project Manager 09-D-14 One White Flint North 11555 Rockville Pike Rockville, MD 20852 U.S. Nuclear Regulatory Commission Region IV 1600 East Lamar Blvd.

Arlington, TX 76011-4511

RBG-47874 Page 2 of 2 NRC Senior Resident Inspector Attn: Mr. Jeff Sowa 5485 U.S. Highway 61, Suite 1 St. Francisville, LA 70775 Public Utility Commission of Texas Attn: PUC Filing Clerk 1701 N. Congress Avenue P. O. Box 13326 Austin, TX 78711 -3326 INPO (via ICES reporting)

RBF1 0140

NRC FORM 366 (04-2018)

U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)

(See Page 2 for required number of digits/characters for each block)

(See NUREG-1022, R.3 for instruction and guidance for completing this form htlp'/Iwww.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1 022/r3/1 APPROVED BY OMS: NO. 3150~104 EXPIRES: 03/31/2020 Est'mated burden per response to comply willi Ih~ mandatolY coIlec:lon request 80 hour9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />..

Reported lessons learned are IncOfporated into the ke1Sing process and 'ed back to IndustlY. Send comments regarding burden esllmale Ie !he Informa:ion SeNices Branch (T-2 F43). U.S. Nuclear RegulatolY Commlss'on, Washington. DC 20555-000t. or by.. mail to Infocolects.Resource@nrc.gov, and 10 the Desk O'fieer, Office of Information and RegulatolY A~aJr., NEOS.l 0202, (J15CJ.<l104), Ofice of Management and Budge~

Washington, DC 20503. If 8 means used to Impose an Information eclection does not display a currendy valid OMS control number, lhe NRC may not conduct or sponsor, and a person Is nol required to respond to the information coIection.

River Bend Station - Unit 1 05000 458

4. Title Unanalyzed Condition due to Inadequate Protection from Tornado Generated Missiles

5. Event Date Month Day Year 05 04 2018

6. LER Number Year 2018 -

I Sequential I Number 004 Rev No.

00

7. Report Date Month Day Year 07 03 2018 Facility Name NA Facility Name NA

3. Page 1

OF 3

8. Other Facilities Involved Docket Number 05000 Docket Number 05000

9. Operating Mode

11. This Report is Submitted Pursuant to the Requirements of 10 CFR §: (Check all that apply) o 20.2201 (b) o 20.2203(a)(3)(I) o 50.73(a)(2)(II)(A) 0 50.73(a)(2)(vili)(A) 1 Cd 50.73(a)(2)(1I)(8) 0 50.73(a)(2)(vlIl)(8) o 20.2201 (d) o 20.2203(a)(3)(II) o 20.2203(a)(l) o 20.2203(a)(4) o 50.73(a)(2)(lli) 0 50.73(a)(2)(ix)(A) o 20.2203(a)(2)(I) o 50.36(c)(1)(I)(A) o 50.73(a)(2)(iv)(A) 0 50.73(a)(2)(x)

10. Power Level o 20.2203(a)(2)(1I) o 50.36(c)(1)(II)(A) o 50.73(a)(2)(v)(A) 0 73.71(a)(4) o 20.2203(a)(2)(III) o 50.36(c)(2) o 50.73(a)(2)(v)(8) 0 73.71(a)(5) o 20.2203(a)(2)(iv) o 50.46(a)(3)(II)

D 50.73(a)(2)(v)(C)

D 73.77(a)(l) 100 o 20.2203(a)(2)(v) o 50.73(a)(2)(I)(A)

Cd 50.73(a)(2)(v)(D) 0 73.77(a)(2)(I) o 20.2203(a)(2)(vl)

Cd 50.73(a)(2)(I)(8)

Cd 50.73(a)(2)(vll) 0 73.77(a)(2)(il) o 50.73(a)(2)(I)(C) o Other (Specify in Abstract below or in 05000- 1 458 l YE" 12018 1 _ 1 SEQUENTIAL REV NUMBER NO.

004 1-0 term comprehensive compensatory measures were developed and implemented in accordance with DSS-ISG-2016-01 fA,ppendix A. Plans are underway to resolve the non-compliances with modifications or probabilistic analysis and are being tracked in the station's corrective action program.

PREVIOUS OCCURRENCE EVALUATION [There have been no similar events reported by River Bend Station.

SAFETY SIGNIFICANCE

lAs stated in the NRC Enforcement Guidance Memorandum,15-002, the basis for exercising enforcement discretion is a result of a generic risk analysis performed by the Office of Nuclear Reactor Regulation (NRR), Division of Risk Assessment (ORA). The assessment documents a conservative, bounding-type analysis of the risk significance for plant facilities that may not be in compliance with their tornado missile protection licensing basis. The generic nature of this analysis did not afford the staff the capability to assess plant-specific tornado missile protections which likely exist at many reactors in accordance with their Current License Basis, and that would result in lower risk determinations. It also did not consider the plant-specific nature of the non-compliances or the redundancies of SSCs. The generic analysis assumed that core damage would occur if a tornado hit a plant located in the most active tornado region in the country and that it caused a tornado-generated missile to fail all emergency core cooling equipment at the plant with no ability to recover. Given this conservative assumption, the core-damage frequency (CDF) was calculated to be 4E-5 per year, which is more than an order of magnitude below the 1 E-3 per year threshold provided in the NRR Office Instruction LlC-504, Integrated Risk-Informed Decision-Making Process for Emergent Issues. Per LlC-504, 1 E-03 per year provides a guideline that can be used to determine whether additional regulatory actions should be considered to place a plant in a safe condition.

Consequently, the staffs study established that the CDF associated with tornado missile related non-compliances are well below CDFs requiring immediate regulatory action.

As a result of the NRR ORA (ref. EGM 15-002) generic bounding risk analysis, it was concluded that this issue is of low risk significance. This event was of minimal significance to the health and safety of the public.

!Tornados are not postulated to occur during or initiate any of the design basis accidents described in UFSAR Chapter 6 or

15. As a result although the issue is being reported as a condition which had the potential for causing the loss of a safety function, no safety function was lost due to this event.

(NOTE: Energy Industry Identification System component function identifier and system name of each component or system referred to in the LER are annotated as (**XX**) and [XX), respectively. Page 3

of 3