ML16070A027

NRR E-mail Capture - Preliminary Additional RAIs Related to the Request for Exemption Regarding MSIV Bypass Valves

ML16070A027
Person / Time
Site:	Byron, Braidwood
Issue date:	03/02/2016
From:	Joel Wiebe Plant Licensing Branch III
To:	Bauer J Exelon Corp
References
Download: ML16070A027 (3)

Text

NRR-PMDAPEm Resource From: Wiebe, Joel Sent: Wednesday, March 02, 2016 9:31 AM To: Joseph Bauer

Subject:

Preliminary Additional RAIs related to the Request for Exemption Regarding MSIV Bypass valves The purpose of preliminary RAIs is to ensure the questions are clear and understandable. Let me know within 1 week of receipt of this e-mail if a clarification call is necessary.

In reviewing the Exelon Generation Company, LLC (Exelons) submittal dated April 6, 2015 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15097A123), related to the request for exemption from Title 10 of the Code Of Federal Regulations (10 CFR), Section 50.55a, Paragraph (h)(2),

Codes and Standards, for the Braidwood Station, Units 1 and 2, and Byron Station, Unit Nos. 1 and 2, the U.S. Nuclear Regulatory Commission (NRC) staff has determined that the following information is needed in order to complete its review:

1. By e-mail from Russell Haskell dated May 11, 2015 (ADAMS Accession No. ML15131A424), the NRC staff accepted Exelons April 6, 2015, submittal. After further consideration, the NRC staff has determined that an exemption to the regulations is not warranted because 10 CFR Part 50.55a (z) allows the NRC staff to authorize the use of alternatives to requirements in 10 CFR Section 50.55a (h).

Based on the above, the NRC staff will not further consider issuance of an exemption to 10 CFR Section 50.55a (h)(2).

To continue the NRC staff review of the request for use of an alternative, provide a clear statement of the alternative requested and demonstrate that: (1) the alternative provides an acceptable level of quality and safety, or (2) hardship without a compensating increase in quality and safety as required by 10 CFR Section 55a (z). Examples of hardship or unusual difficulty are identified in the NRC staff Office Instruction, LIC-102, Relief Request Reviews, Revision 2, dated August 24, 2009 (ADAMS Accession No. ML091380595). If portions of this information is already available on the docket, you may provide specific reference to the information. You should also clearly state that you are no longer requesting an exemption to 10 CFR Section 50.55a (h)(2).

2. The submittal dated April 16, 2015, states that each accident scenario that requires a main steam line isolation has been reviewed. The submittal, in the evaluation of the Steam Generator Tube Rupture event, states that Emergency Operating Procedure, B(w)EP-3, Steam Generator Tube Rupture, directs the operator to isolate the MSIV and bypass valve on the ruptured steam generator. The NRC staff is aware of other Emergency Operating Procedures that contain direction to operators to isolate MSIVs and bypass valves.

Provide the following:

a. Identify all emergency operating procedures (EOPs) that direct the operator to isolate one or more MSIVs and bypass valves.

b. Evaluate the related event(s) in the above identified EOPs to determine if it is impacted by the absence of a system level closure of the MSIV bypass valves.

c. Provide a discussion of these events and provide summaries of the impacts

3. In the response to the request for additional information (RAI) 1.b.ii, in letter dated January 29, 2016 (ADAMS Accession No. ML16029A408), Exelon has now provided two independent methods to manually close the MSIV bypass valves.

1

Provide clarification whether or not the single-failure aspect in Section 4.17 of Institute of Electrical and Electronic Engineers Std. 279 is satisfied by the two manual means of closing the valves.

4. In the response to RAI 1.c, in letter dated January 29, 2016, Exelon stated These position controllers receive power from 125V AC power and are independent from the manual single valve control switches and have a different power source than the automatic MSL [main steamline] isolation signals.

Provide clarification whether or not the term different power sources can be applied to the two means of closing the valves and if they are both safety-related.

2

Hearing Identifier: NRR_PMDA Email Number: 2700 Mail Envelope Properties (c51ea18965cc4b868c288006ad6fae90)

Subject:

Preliminary Additional RAIs related to the Request for Exemption Regarding MSIV Bypass valves Sent Date: 3/2/2016 9:31:03 AM Received Date: 3/2/2016 9:31:00 AM From: Wiebe, Joel Created By: Joel.Wiebe@nrc.gov Recipients:

"Joseph Bauer" <Joseph.Bauer@exeloncorp.com>

Tracking Status: None Post Office: HQPWMSMRS07.nrc.gov Files Size Date & Time MESSAGE 3851 3/2/2016 9:31:00 AM Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received:

NRR-PMDAPEm Resource From: Wiebe, Joel Sent: Wednesday, March 02, 2016 9:31 AM To: Joseph Bauer

Subject:

Preliminary Additional RAIs related to the Request for Exemption Regarding MSIV Bypass valves The purpose of preliminary RAIs is to ensure the questions are clear and understandable. Let me know within 1 week of receipt of this e-mail if a clarification call is necessary.

In reviewing the Exelon Generation Company, LLC (Exelons) submittal dated April 6, 2015 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15097A123), related to the request for exemption from Title 10 of the Code Of Federal Regulations (10 CFR), Section 50.55a, Paragraph (h)(2),

Codes and Standards, for the Braidwood Station, Units 1 and 2, and Byron Station, Unit Nos. 1 and 2, the U.S. Nuclear Regulatory Commission (NRC) staff has determined that the following information is needed in order to complete its review:

1. By e-mail from Russell Haskell dated May 11, 2015 (ADAMS Accession No. ML15131A424), the NRC staff accepted Exelons April 6, 2015, submittal. After further consideration, the NRC staff has determined that an exemption to the regulations is not warranted because 10 CFR Part 50.55a (z) allows the NRC staff to authorize the use of alternatives to requirements in 10 CFR Section 50.55a (h).

Based on the above, the NRC staff will not further consider issuance of an exemption to 10 CFR Section 50.55a (h)(2).

To continue the NRC staff review of the request for use of an alternative, provide a clear statement of the alternative requested and demonstrate that: (1) the alternative provides an acceptable level of quality and safety, or (2) hardship without a compensating increase in quality and safety as required by 10 CFR Section 55a (z). Examples of hardship or unusual difficulty are identified in the NRC staff Office Instruction, LIC-102, Relief Request Reviews, Revision 2, dated August 24, 2009 (ADAMS Accession No. ML091380595). If portions of this information is already available on the docket, you may provide specific reference to the information. You should also clearly state that you are no longer requesting an exemption to 10 CFR Section 50.55a (h)(2).

2. The submittal dated April 16, 2015, states that each accident scenario that requires a main steam line isolation has been reviewed. The submittal, in the evaluation of the Steam Generator Tube Rupture event, states that Emergency Operating Procedure, B(w)EP-3, Steam Generator Tube Rupture, directs the operator to isolate the MSIV and bypass valve on the ruptured steam generator. The NRC staff is aware of other Emergency Operating Procedures that contain direction to operators to isolate MSIVs and bypass valves.

Provide the following:

a. Identify all emergency operating procedures (EOPs) that direct the operator to isolate one or more MSIVs and bypass valves.

b. Evaluate the related event(s) in the above identified EOPs to determine if it is impacted by the absence of a system level closure of the MSIV bypass valves.

c. Provide a discussion of these events and provide summaries of the impacts

3. In the response to the request for additional information (RAI) 1.b.ii, in letter dated January 29, 2016 (ADAMS Accession No. ML16029A408), Exelon has now provided two independent methods to manually close the MSIV bypass valves.

1

Provide clarification whether or not the single-failure aspect in Section 4.17 of Institute of Electrical and Electronic Engineers Std. 279 is satisfied by the two manual means of closing the valves.

4. In the response to RAI 1.c, in letter dated January 29, 2016, Exelon stated These position controllers receive power from 125V AC power and are independent from the manual single valve control switches and have a different power source than the automatic MSL [main steamline] isolation signals.

Provide clarification whether or not the term different power sources can be applied to the two means of closing the valves and if they are both safety-related.

2

Hearing Identifier: NRR_PMDA Email Number: 2700 Mail Envelope Properties (c51ea18965cc4b868c288006ad6fae90)

Subject:

Preliminary Additional RAIs related to the Request for Exemption Regarding MSIV Bypass valves Sent Date: 3/2/2016 9:31:03 AM Received Date: 3/2/2016 9:31:00 AM From: Wiebe, Joel Created By: Joel.Wiebe@nrc.gov Recipients:

"Joseph Bauer" <Joseph.Bauer@exeloncorp.com>

Tracking Status: None Post Office: HQPWMSMRS07.nrc.gov Files Size Date & Time MESSAGE 3851 3/2/2016 9:31:00 AM Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received: