GO2-19-121, Supplemental Information Related to Exigent License Amendment Request for Change to Technical Specification 3.8.7 Distribution Systems-Operating

Supplemental Information Related to Exigent License Amendment Request for Change to Technical Specification 3.8.7 Distribution Systems-Operating

ML19228A291
Person / Time
Site:	Columbia
Issue date:	08/16/2019
From:	Schuetz R Energy Northwest
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
GO2-19-121
Download: ML19228A291 (5)

Text

R. E. Schuetz ENERGY Columbia Generating Station P.O. Box 968, PE23 Richland, WA 99352-0968 NORTHWEST Ph. 509.377.2425 l F. 509.377.4150 reschuetz@energy-northwest.com August 16, 2019 GO2-19-121 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Subject:

COLUMBIA GENERATING STATION, DOCKET NO. 50-397 SUPPLEMENTAL INFORMATION RELATED TO EXIGENT LICENSE AMENDMENT REQUEST FOR CHANGE TO TECHNICAL SPECIFICATION 3.8.7 DISTRIBUTION SYSTEMS-OPERATING

Reference:

Letter from R.E. Schuetz, Energy Northwest to NRC, dated August 15, 2019 (ADAMS Accession Number ML19227A370)

Dear Sir or Madam:

By the referenced letter Energy Northwest submitted exigent License Amendment Request (LAR) to revise the Columbia Generating Station (Columbia) Technical Specification (TS) 3.8.7 Distribution Systems - Operating. This amendment requested to add a one-time extension of the Completion Time of TS Action 3.8.7.A associated with Division 1 Alternating Current (AC) electrical power distribution inoperability.

Following a phone discussion with Mr. J Kloss of your staff on August 16, 2019, a determination was made to supplement the referenced letter. The enclosure to this letter contains the supplemental information.

The No Significant Hazards Consideration Determination (NSHCD) provided in the original submittal is not altered by this submittal.

No new commitments are being made by this letter or the enclosure.

If there are any questions or if additional information is needed, please contact Mr. D.W. Gregoire, Regulatory Affairs Manager, at 509-377-8616.

G02-19-121 Page 2 of 2 I declare under penalty of perjury that the foregoing is true and correct.

,+~

Executed this _ / i?_ _ day of August 2019.

Enclosure:

As stated cc: NRC RIV Regional Administrato r NRC Senior Resident lnspector/988C NRC NRR Project Manager CD Sonoda - BPA/1399 (email)

EFSECutc.wa.gov - EFSEC (email)

E Fordham - WDOH (email)

R Brice-WDO H (email)

WA Horin - Winston & Strawn

GO2-19-121 Page 1 of 3 SUPPLEMENTAL INFORMATION The following supplemental information is provided to assist in the review of Energy Northwests exigent license amendment request (LAR) on August 15, 2019.

The exigent LAR is considered a one-time exigent request based on a deterministic evaluation that is further supported with risk insights described in the letter sent on August 15, 2019. The basis for asking for an exigent change relates to the need to replace the power transformer (E-TR-7A/2) that provides power to 120/240V AC power panel E-PP-7AF. Power panel E-PP-7AF is a required electrical distribution panel to satisfy division 1 AC subsystem operability. The time to replace the transformer exceeds the allowed completion times described in Technical Specifications (TS) 3.8.7 Condition A.

The following deterministic evaluation for this one-time exigent LAR was considered:

1. Main Control Room During the time Power panel E-PP-7AF is de-energized, the Main Control Room will remain available to provide sufficient controls and indications for normal operation and to safely shutdown the reactor and maintain it shutdown should it be necessary.

2. Remote Shutdown System (RSS)

Power panel E-PP-7AF provides a small subset of indications and controls on the remote shutdown panels. Other electrical panels that provide power to indications and controls on the remote shutdown panel include 120V AC panel E-PP-8AF and 125V DC Panels E-DP-S1/1D, E-DP-S1/2D. These power panels will be maintained in service and operable to support remote shutdown panel capabilities while work is being conducted on supply transformer E-TR-7A/2.

Even though the PRA evaluation provided in the August 15, 2019 supports an extremely low probability of a fire requiring an evacuation of the Main Control Room, a detailed evaluation of the loss of each of the impacted loads from power panel E-PP-7AF, which are primarily associated with the remote shutdown panel, was conducted.

The loss of loads were evaluated to determine the impact on the RSS ability for:

• prompt hot shutdown of the reactor including necessary instrumentation and controls to maintain the unit in a safe condition during hot shutdown, and

• the capability for subsequent cold shutdown of the reactor through the use of suitable procedures

GO2-19-121 Page 2 of 3 Specific loads energized from E-PP-7AF that were identified as having the potential to impact the ability to accomplish the RSS functions listed above are addressed below:

• RHR-V-6A, Suction Valve to Residual Heat Removal (RHR) Pump 2A Loss of power to E-PP-7AF would result in the loss of the both the ability to remotely control and verify the valve position for RHR-V-6A. The main control room evacuation procedure contains steps to verify RHR-V-6A is shut; its normal position. RHR Loop A is still available for suppression pool cooling through test return valve and alternate shutdown cooling through the low pressure core injection valve. All necessary valves (RHR-V-4A, RHR-V-24A and RHR-V-42A) receive motive and control power from a separate unaffected electrical panel, E-MC-7BA. (Reference FSAR Figure 5.4-15.1)

• RHR-V-53B Loop B RHR Shutdown Cooling Return Isolation Loss of power to E-PP-7AF would result in the loss of the both the ability to remotely control and verify the valve position for RHR-V-53B. The main control room evacuation procedure contains steps to use alternate shutdown cooling in the event that RHR-V-53B is not operable. In this case the injection path for RHR-B to the reactor pressure vessel is through the division 2 powered normal low pressure core injection valve RHR-V-42B which receives motive and control power from unaffected power panel E-MC-8A. (Reference FSAR Figure 5.4-15.2)

In addition, a loss of power panel E-PP-7AF was simulated in the plant control room and remote shutdown panel simulators along with use of the control room evacuation procedures to validate the evaluation conclusions regarding the impact on the RSS functions.

In summary, the evaluation concluded that there was sufficient redundancy in the plant design or acceptable alternatives described in procedural guidance to support the conclusion that the loss of loads powered from E-PP-7AF would not impact the ability of the RSS to safely support its required functions.

3. FLEX In addition to the RSS capabilities, further defense in depth is provided outside the main control room by implementation of FLEX mitigating strategies at Columbia consistent with NEI 12-06 which can be used to address extended loss of all AC power which bounds the loss of power panel E-PP-7AF.

In conclusion, through a deterministic evaluation which includes an assessment of defense-in-depth, and based on the risk considerations provided in the August 15, 2019 letter:

1. There is a reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner;

GO2-19-121 Page 3 of 3

2. Such activities will be conducted in compliance with the Commission's regulations; and

3. Issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

Energy Northwest has determined that the proposed changes do not require any exemptions or relief from regulatory requirements other than the TS. The changes do not affect conformance with the intent of any GDC differently than described in the Updated Final Safety Analysis Report.