Text

NRR E-mail Capture - (CAC Nos. MF6079 - MF6082) Request for Additional Information Byron/Braidwood MSIV Bypass Valve Exemption Request
	ML16005A007
Person / Time
Site:	Byron, Braidwood
Issue date:	12/31/2015
From:	Haskell R; Plant Licensing Branch III
To:	Bauer J; Exelon Corp
References
	MF6079, MF6080, MF6081, MF6082
	Download: ML16005A007 (6)
	v • d • e

NRR-PMDAPEm Resource From: Haskell, Russell Sent: Thursday, December 31, 2015 12:25 PM To: Bauer, Joseph A.:(GenCo-Nuc)

Cc: Oesterle, Eric; Borromeo, Joshua; Beacom, Royce; Poole, Justin; Wiebe, Joel

Subject:

(CAC Nos. MF6079 - MF6082) Request for Additional Information Re: Byron/Braidwood MSIV Bypass Valve Exemption Request Attachments: MF6079_MF6082 - Byron_Braidwood_MSIV Bypass_RAIs_final.docx Importance: High

Joe, By letter dated April 6, 2015 (Agencywide Documents Access and Management System Accession No. ML15097A123), Exelon Generation Corporation (EGC, the licensee) submitted a request pursuant to Title 10 of the Code of Federal Regulations (10 CFR) Part 50.12(a)(2)(ii) for exemption from 10 CFR 50.55a, Codes and standards, paragraph (h)(2), Protection Systems, regarding Braidwood Station, Units 1 and 2, and Byron Station, Unit Nos. 1 and 2, Facilities Operating Licenses. The proposed exemption would eliminate the requirement for manual system level initiation of the main steam line bypass valves isolation per the criteria stated in Institute of Electrical & Electronics Engineers (IEEE) [Standard] Std. 279, Section 4.17, Manual Initiation.

The purpose of this message is to summarize the staffs position regarding RAIs for the Byron/Braidwood MSIV Bypass Proposed Exemption Request:

For the record, you and I had a phone conversation on December 23, 2015 to essentially compare notes regarding the clarification call between NRC/Exelon, held back on November 23, 2015.

As a result of our discussion, including my discussions with NRC staff, the NRC intends to formalized these RAIs on the BY/BW dockets (as attached). Please note this final set reflects; minor edits, a deletion of RAI #3a, and preservation of RAI # 7 a-c. This version supersedes any previous RAIs distributed as draft. Furthermore, please be advised, to support the staffs Safety Evaluation, the NRC is requesting EGCs response to these RAIs NLT January 29, 2016.

I will return to the office on Thursday January 7, 2016 should you have any questions/comments regarding this request.

Thank you.

Russell S. Haskell II United States Nuclear Regulatory Commission (NRC)

Reactor Systems Engineer NRR/DORL/LPL 3-2 P.O.C.:Dresden Nuclear Power Station, Units 2 and 3

+ Russell.Haskell@NRC.Gov; ( (301) 415-1129; Office: O-7D21; Mail-Stop O-8G9A 1

Hearing Identifier: NRR_PMDA Email Number: 2569 Mail Envelope Properties (db9b1793973a48f38b8d7cce1b882d80)

Subject:

(CAC Nos. MF6079 - MF6082) Request for Additional Information Re:

Byron/Braidwood MSIV Bypass Valve Exemption Request Sent Date: 12/31/2015 12:25:22 PM Received Date: 12/31/2015 12:25:23 PM From: Haskell, Russell Created By: Russell.Haskell@nrc.gov Recipients:

"Oesterle, Eric" <Eric.Oesterle@nrc.gov>

Tracking Status: None "Borromeo, Joshua" <Joshua.Borromeo@nrc.gov>

Tracking Status: None "Beacom, Royce" <Royce.Beacom@nrc.gov>

Tracking Status: None "Poole, Justin" <Justin.Poole@nrc.gov>

Tracking Status: None "Wiebe, Joel" <Joel.Wiebe@nrc.gov>

Tracking Status: None "Bauer, Joseph A.:(GenCo-Nuc)" <joseph.bauer@exeloncorp.com>

Tracking Status: None Post Office: HQPWMSMRS05.nrc.gov Files Size Date & Time MESSAGE 1997 12/31/2015 12:25:23 PM MF6079_MF6082 - Byron_Braidwood_MSIV Bypass_RAIs_final.docx 36799 Options Priority: High Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received:

REQUEST FOR ADDITIONAL INFORMATION REQUEST FOR EXEMPTION FROM 10 CFR 50.55a, CODES AND STANDARDS, PARAGRAPH (h)(2), PROTECTION SYSTEMS.

BRAIDWOOD UNITS 1 AND 2, AND BYRON UNIT NOS. 1 AND 2 (TAC NOS. MF6079, MF6080, MF6081, AND MF6082)

By letter dated April 6, 2015 (Agencywide Documents Access and Management System Accession No. ML15097A123), Exelon Generation Corporation (the licensee) submitted a request pursuant to Title 10 of the Code of Federal Regulations (10 CFR) Part 50.12(a)(2)(ii) for exemption from 10 CFR 50.55a, Codes and standards, paragraph (h)(2), Protection Systems, regarding Braidwood Station, Units 1 and 2, and Byron Station, Unit Nos. 1 and 2, Facilities Operating Licenses. The proposed exemption would eliminate the requirement for manual system level initiation of the main steam line bypass valves isolation per the criteria stated in Institute of Electrical & Electronics Engineers (IEEE) [Standard] Std. 279, Section 4.17, Manual Initiation. The technical review branch for instrumentation and control has identified the need for additional information to complete the review of the exemption request:

1. As the request states, the exemption would eliminate the requirement to meet the criteria stated in IEEE Std. 279, Section 4.17, "Manual Initiation," only for the Main Steam Isolation Valve (MSIV) bypass valves manual isolation function. However, the criterion of Section 4.17 consists of three statements. The first one concerns the system level initiation; the second concerns single failure; and the third concerns the manual initiation function depending on a minimum of equipment. The questions below will address these three sections by addressing the regulatory positions of the staff in RG 1.62, Manual Initiation of Protective Actions (October 1973).

a. Regulatory position C.2, states: Manual initiation of a protective action at the system level should perform all actions performed by the automatic initiation and provides examples of those types of actions.

Provide a list of all actions that are done at the automatic initiation, how they are done, and how they are confirmed, at the manual level initiation of the MSIV and MSIV bypass valves.

b. P.5 of the exemption request states the existing individual MSIV bypass valves manual control switches are single train switches such that a single failure of a switch could prevent the manual initiation of the protective action (i.e., prevent closure of the MSIV bypass valve).

Provide justification for the current configuration not meeting the single failure criterion, 4.2, of IEEE 279.

i. Has there been an analysis done to determine the effects of one or more MSIV bypass valves failed open?

ii. Explain how the containment isolation function is single failure proof and the current configuration is acceptable.

c. Regulatory position C.4 also states: The amount of equipment common to both manual and automatic initiation should be kept to a minimum.

Describe the equipment and circuitry, or portions thereof, which are common to automatic and manual initiation, whether it be component or system level initiation.

2. Consistent with RG 1.62; Manual Initiation of Protective Actions, (dated October 1973),

Regulatory Position 6 states, Manual initiation of protective action at the system level should be so designed that once initiated, it will go to completion as required in Section 4.16 of IEEE Std. 279-1971.

a. Explain the additional actions involved with the MSIV bypass valve that would be necessary to be equivalent to the automatic initiation described above to insure it has gone to completion.

b. Describe the type of switch, the positions available, any spring-return actions, and what is required to manipulate it. Also include necessary indications that confirm the actions have taken place.

3. Review by the NRC staff of manual controls as required by IEEE Std. 279-1971, Clause 4.17, includes confirmation that the characteristics of the controls allow plant operators to take appropriate manual actions during plant conditions under which they would be necessary.

Is there a time limitation to manipulate both sets of switches? Is this identified by procedure and part of a drill or exercise?

4. Page 3 of the Request for Exemption states that the MSIV bypass valves are also containment isolation valves.

a. Since the main steam line manual isolation switches do not operate the bypass valves, do the group-level Containment Isolation switches operate the bypass valves?

b. Was the original intent of the MSIV bypass valve manual control switches to be used for testing only?

5. Regulatory position C.3 of RG 1.62 includes: The switches for manual initiation of protective actions at the system level should be located in the control room and be easily accessible to the operator so that action can be taken in an expeditious manner.

Explain, or illustrate by figure preferably, the relative physical location of switches and indicators used for the system level main steam line manual isolation and the same for individual MSIV bypass valves switches and indicators.

6. The exemption request states that the description of the modification to eliminate the non-conformance with the requirements of IEEE Std. 279 is that it will be costly.

Describe the major modifications to the systems, structures and components (SCCs) as well as the impacts on the schedule and operation of the Byron/Braidwood Station units.

7. Per discussion in the Background Section of the LAR, the conclusion is made that the TS are consistent with actual plant configuration from inspection of Table 3.3.2-1, Function 4 of the TS and the bases. However the staff noted three inconsistencies between the TS and actual plant configuration, as described below.

a. Based on a review of the current TS Table 3.3.2-1, Function 4.a, Manual Initiation, Mode 2 and Mode 3 have an associated Note C which states Except when all Main Steam Isolation Valves (MSIVs) are closed. While the MSIV bypass valves are unmentioned in the note, it does not preclude them from this TS since the main steam isolation function is accomplished by closure of the MSIVs and their associated bypass valves as discussed in Section II.3 of the LAR. Further, when the bypass valves are open and the MSIVs are closed during startup, you need to have manual initiation capability of the bypass valves. Therefore, actual plant configuration is not consistent with the TS.

b. Related to RAI-1a, Note C for Function 4.a, Manual Initiation applies to Mode 2 and Mode 3. It does not apply to Mode 1. Since the main steam isolation function is accomplished by closure of the MSIVs and their associated bypass valves as discussed in Section II.3 of the LAR, manual initiation of the bypass valves are required in Mode 1.

Therefore, actual plant configuration is not consistent with the TS.

c. As discussed in RAI-1a and RAI-1b, Function 4.a applies to the bypass valves.

Function 4.a. requires two channels to be operable to meet the LCO. However, as discussed in the LAR, the manual initiation of the bypass valves are single train; therefore, actual plant configuration is not consistent with the TS.

Explain why additional TS revisions are not necessary given the actual plant configuration.

8. Per Section II.3 of the amendment, it is noted that individual MSIV bypass valve switches are single train switches. Per 10 CFR Appendix A, General Design Criterion (GDC) 21, Protection system reliability and testability, (1): no single failure results in the loss of a protection function.

Since the MSIV bypass valves are included in protection systems, discuss how GDC 21 is met since the manual switches are single train.

9. Per Section II.2 of the amendment, it is noted that the MSIV bypass valves are also containment isolation valves. TS Table 3.3.2-1, Function 3 governs the containment isolation function. From a review of this TS, there is no indication that manual initiation only applies to the MSIVs and not their associated bypass valves.

Provide justification why it is not necessary to update the TSs to reflect the lack of a system level MSIV bypass valve switch.

10. When determining the limiting single failure for the safety analyses; Was it assumed that the MSIV bypass valves had a manual system level switch in addition to the manual single operation switch? If this was assumed, provide additional justification of the limiting single failure determination.

11. Is there a single failure that would cause all four MSIV bypass valves manual initiation function to fail? If so, provide justification this is an acceptable condition with respect to the applicable safety analyses.

12. Elaborate on what components are credited during the Steam Generator Tube Rupture (SGTR) event if a MSIV bypass valve fails to close on the faulted steam generator. Are the credited components safety related or non-safety related?