DCL-12-057, Supplement to PG&E Letter DCL-12-017, Response to NRC Request for Additional Information: NRC Question 1

Supplement to PG&E Letter DCL-12-017, Response to NRC Request for Additional Information: NRC Question 1

ML12153A343
Person / Time
Site:	Diablo Canyon
Issue date:	05/31/2012
From:	Becker J Pacific Gas & Electric Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
DCL-12-057
Download: ML12153A343 (11)

Text

Pacific Gas and Electric Company James R. Becker Diablo Canyon Power Plant Site Vice President Mail Code 104/6 P. O. Box 56 Avila Beach, CA 93424 805.545.3462 Internal: 691.3462 May 31,2012 Fax: 805.545.6445 PG&E Letter DCL-12-057 u.s. Nuclear Regulatory Commission 10 CFR 50.90 ATTN: Document Control Desk Washington, DC 20555-0001 Docket No. 50-275, OL-DPR-80 Docket No. 50-323, OL-DPR-82 Diablo Canyon Units 1 and 2 Supplement to PG&E Letter DCL-12-017. Response to NRC Request for Additional Information: NRC Question 1

References:

1. PG&E Letter DCL-11-059, "License Amendment Request 11-04, Revision to Technical Specification (TS) 3.6.6, 'Containment Spray and Cooling Systems,' TS 3.7.5, 'Auxiliary Feedwater (AFW)

System,' TS 3.8.1, 'AC Sources - Operating,' TS 3.8.9, 'Distribution Systems - Operating,' and TS Example 1.3-3," dated June 1, 2011

2. PG&E Letter DCL-12-017, Response to NRC Request for Additional Information Regarding PG&E Letter DCL-11-059, "License Amendment Request 11-04, Revision to Technical Specification (TS) 3.6.6, 'Containment Spray and Cooling Systems,' TS 3.7.5, 'Auxiliary Feedwater (AFW) System,' TS 3.8.1,

'AC Sources - Operating,' TS 3.8.9, 'Distribution Systems -

Operating,' and TS Example 1.3-3," dated February 6, 2012 In Reference 1, Pacific Gas and Electric Company (PG&E) submitted a license amendment request to revise Technical Specification (TS) 3.6.6, "Containment Spray and Cooling Systems," TS 3.7.5, "Auxiliary Feedwater (AFW) System," TS 3.8.1, "AC Sources - Operating," TS 3.8.9, "Distribution Systems - Operating," and TS Example 1.3-3.

The NRC staff provided a request for additional information (RAI) via e-mail, dated January 5, 2012. PG&E provided a response to the RAI in Reference 2. The Enclosure to this letter provides a supplement to the Reference 2 response to NRC RAI question 1.

PG&E makes no regulatory commitments (as defined by NEI 99-04) in this letter.

If you have any questions or require additional information, please contact Mr. Tom Baldwin at (805) 545-4720.

A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway. Comanche Peak. Diablo Canyon

• Palo Verde

• San Onofre

• South Texas Project. Wolf Creek

__ Document Control Desk PG&E Letter DCL-12-057

~&~ May 31,2012 I & Page 2 I state under penalty of perjury that the foregoing is true and correct.

Executed on May 31,2012.

Si~CereIY, "

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Jam-e J:<.Becke~ -,.--

Site Vice President Mjrm/4557/50329767 Enclosure cc: Diablo Distribution cc/enc: Elmo E. Collins, NRC Region IV Michael S. Peck, NRC Senior Resident Inspector Joseph M. Sebrosky, NRR Project Manager A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

• Comanche Peak

• Diablo Canyon

• Palo Verde

• San Onofre

• South Texas Project

• Wolf Creek

Enclosure PG&E Letter DCL-12-057 Supplement to PG&E Letter DCL-12-017 Response to NRC Request for Additional Information: NRC Question 1

References:

1. PG&E Letter DCL-11-059, "License Amendment Request 11-04, Revision to Technical Specification (TS) 3.6.6, 'Containment Spray and Cooling Systems,' TS 3.7.5, 'Auxiliary Feedwater (AFW) System,'

TS 3.8.1, 'AC Sources - Operating,' TS 3.8.9, 'Distribution Systems -

Operating,' and TS Example 1.3-3," dated June 1, 2011

2. PG&E Letter DCL-12-017, Response to NRC Request for Additional Information Regarding PG&E Letter DCL-11-059, "License Amendment Request 11-04, Revision to Technical Specification (TS) 3.6.6, 'Containment Spray and Cooling Systems,' TS 3.7.5, 'Auxiliary Feedwater (AFW) System,' TS 3.8.1, 'AC Sources - Operating,' TS 3.8.9, 'Distribution Systems - Operating,' and TS Example 1.3-3,"

dated February 6,2012 In Reference 1, Pacific Gas and Electric Company (PG&E) submitted a license amendment request that proposed changes to several technical specifications (TSs) including changes to TS 3.7.5, "Auxiliary Feedwater (AFW) System." The license amendment request included changes to be consistent with TSTF traveler 412, Revision 3, "Allow 7 Day Completion Time for a Turbine-driven AFW Pump Inoperable."

During a public meeting on May 8, 2012, TSTF traveler 412 was discussed, including the NRC staff's issues associated with the portion of the TSTF traveler associated with a provision for 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> completion time for an inoperable motor-driven AFW pump coincident with one inoperable steam supply to the steam-driven AFW pump. The NRC staff's issues are documented in an April 12, 2012, memorandum from Greg Casto to Robert Elliot (ADAMS Accession No. ML121030032).

Because of the issues with TSTF traveler 412 identified during the May 8, 2012, meeting and in the April 12, 2012, letter, PG&E is proposing to amend the response provided to NRC question number 1 in Reference 2.

NRC Question 1:

On page 8 of the application letter dated June 1, 2011, the licensee, PG&E, states, "under the scenario with one steam supply for the turbine-driven auxiliary feedwater pump (TDAFWP) inoperable and one motor-driven auxiliary feedwater pump (MDAFWP) inoperable, a feed line or steam line rupture could challenge the capability of the auxiliary feedwater (AFW) system to provide feedwater." The staff is evaluating conditions of the plant during scenarios such as a feedwater line break (FWLB) or a main steamline break (MSLB) on steam generator (SG) 3 occurs when the MDAFWP 1-2 for SG1 and SG2 is inoperable and the steam supply from SG2 to the TDAFWP is inoperable. This scenario would leave only SG4 supplied by MDAFWP 1-3 available. In final safety analysis report (FSAR) Table 6.5-2, the licensee requires a minimum of 390 gpm auxiliary feedwater (AFW) flow to 2 of the 4 intact SGs to mitigate a main feed line 1

Enclosure PG&E Letter DCL-12-057 break. Therefore, in such scenarios the licensee would not meet the design requirement as stipulated in their design basis to mitigate an accident. Hence, the request to continue operations for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> with one steam supply inoperable coincident with an inoperable motor driven pump may result in such postulated scenario that is beyond the current analyzed design basis.

In its draft safety evaluation reporl (SER) for TSTF-412, dated April 14, 2006, the staff considered the possible credit for operators having the ability to remotely feed other SGs from the control room using the operable MDAFWP. Figure 1 in the letter dated June 1, 2011, does show a possible cross tie line between the discharge headers of MDAFWP's. However, in their application the licensee does not mention using the cross tie line to mitigate accidents when the plant is in a degraded condition.

The staff requests the licensee to justify their proposed TS that allows for continued operations for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> in conditions that result in an unanalyzed condition. Note: the licensee can limit the proposed condition, where the inoperable steam supply could only exist on the SG that can be fed by the operable MDAFWP.

PG&E Revised Response:

The NRC staff had included the following note in question 1:

"the licensee can limit the proposed condition, where the inoperable steam supply could only exist on the SG that can be fed by the operable MDAFWP."

PG&E is proposing to remove the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> limiting condition for operation (LCO) in accordance with the above note and replace it with a 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> LCO when the conditions in the above note are met.

PG&E included the following in Reference 1.

INSERT 3 D. Turbine driven AFW tra in D.1 Restore the steam 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> inoperable due to one supply to the turbine inoperable steam supply. driven train to OPERABLE status.

AND OR One motor driven AFW 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> train inoperable. 0.2 Restore the motor driven AFW train to OPERABLE status.

PG&E is proposing the following revision to Reference 1 INSERT 3 as follows:

2

Enclosure PG&E Letter OCL-12-057 O. --------------~()lrE------------- 0.1 Restore the steam 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> supply to the turbine

()nly applicable when the driven train to remaining ()PERABLE

()PERABLE status.

motor driven AFW train provides feedwater to the steam generator with the 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> inoperable steam supply.

0.2 Restore the motor driven AFW train to ()PERABLE lrurbine driven AFW train status.

inoperable due to one inoperable steam supply.

()ne motor driven AFW train inoperable. to the enclosure provides retyped lrS pages (Condition E moved to page 3.7-11). Attachment 2 to the enclosure provides a revised markup to the lrS bases (included for information only).

lrhe revised lrS bases markup includes the following:

With one of the required motor-driven AFW trains (pump or flow path) inoperable and the turbine-driven AFW train inoperable due to one inoperable steam supply, action must be taken to restore the affected equipment to

()PERABLE status within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. Assuming no single active failures when in this condition, the accident (a FWLB or MSLB) could result in the loss of the remaining steam supply to the turbine-driven AFW pump due to the faulted SG.

A note in Condition 0 limits applicability to only when the remaining ()PERABLE motor-driven AFW train provides feedwater to the SG with the inoperable steam supply. lrhis Condition will only apply during the following two scenarios:

1) Motor-driven AFW pump 2 ()PERABLE, motor-driven AFW pump 3 inoperable, and steam supply from SG 2 inoperable, or

2) Motor-driven AFW pump 2 inoperable, motor-driven AFW pump 3

()PERABLE, and steam supply from SG 3 inoperable.

lrhis ensures that if a FWLB were to occur affecting the ()PERABLE motor driven AFW pump, the turbine-driven AFW pump would still be capable of providing AFW to two intact SGs. If a MSLB were to occur on the SG feeding the remaining ()PERABLE steam supply to the turbine-driven AFW pump, the 3

Enclosure PG&E Letter DCL-12-057 OPERABLE motor-driven AFW pump would still be capable of providing AFW to two intact SGs.

If motor-driven AFW pump 2 and the steam supply from SG 3 are inoperable, or if motor-driven AFW pump 3 and the steam supply from SG 2 are inoperable, then Condition E for two inoperable AFW pumps applies.

The 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> Completion Time is reasonable based on the fact that the remaining motor-driven AFW train is capable of providing 100 percent of the AFW flow requirements, and the low probability of an event occurring that would challenge the AFW system.

The proposed changes do not affect the basis for or conclusions of the no significant hazards consideration determination of Reference 1.

4

Enclosure Attachment 1 PG&E Letter DCL-12-057 Revised TS Retype Pages (replace pages 3.7-1 Oa and 3.7-11 previously submitted in DCL-11-059) 1

AFW System 3.7.5 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME B. One or more motor driven B.1 -----------NOTE-------------

AFW trains with automatic No change in valve control of one motor driven demand is required if AFW level control valve per AFW is being relied train inoperable. upon for SG level control.

Place affected AFW Immediately level control valve(s) in manual control with valve demand full open.

OR B.2 Declare the associated Immediately AFW train inoperable.

C. One AFW train inoperable C.1 Restore AFW train to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> I in MODE 1, 2 or 3 for OPERABLE status.

reasons other than

-1 Condition A.

D. --------------NOTE-------------- 0.1 Restore the steam 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> Only applicable when the supply to the turbine remaining OPERABLE driven train to motor driven AFW train OPERABLE status.

provides feedwater to the OR steam generator with the inoperable steam supply. 0.2 Restore the motor driven 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />

---

AFW train to Turbine driven AFW train OPERABLE status.

inoperable due to one inoperable steam supply.

AND One motor driven AFW train inoperable.

(continued)

DIABLO CANYON - UNITS 1 & 2 3.7-10a Unit 1 - Amendment No. ~,4a9, Unit 2 - Amendment No. ~,4+Q,

AFW System 3.7.5 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME E. Required Action and E.1 Be in MODE 3. 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> associated Completion AND Time of Condition A, C, or D not met. 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> E.2 Be in MODE 4.

OR Two AFW trains inoperable in MODE 1, 2 or 3 for reasons other than Condition D.

F. Three AFW trains F.1 -----------NOTE ---------------

inoperable in MODE 1, 2, or LCO 3.0.3 and all other

3. LCO Required Actions requiring MODE changes are suspended until one AFW train is restored to OPERABLE status.

Initiate action to restore Immediately one AFW train to OPERABLE status G. Required AFW train G.1 Initiate action to restore Immediately inoperable in MODE 4. AFW train to OPERABLE status.

DIABLO CANYON - UNITS 1 & 2 3.7-11 Unit 1 - Amendment No. ~,

Unit 2 - Amendment No. ~,

Enclosure Attachment 2 PG&E Letter DCL-12-057 Revised TS Bases Markup Page (for information only) 1

AFW System B 3.7.5 the more restrictive must be met.

0.1 and 0.2 With one of the required motor driven AFW trains (pump or flow path) inoperable and the turbine driven AFW train inoperable due to one inoperable steam supply, action must be taken to restore the affected equipment to OPERABLE status within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. Assuming no single active failures when in this condition, the accident (a FLB or MSLB) could result in the loss of the remaining steam supply to the turbine driven AFW pump due to the faulted SG.

A note in Condition 0 limits applicability to only when the remaining OPERABLE motor driven AFW train provides feedwater to the steam generator with the inoperable steam supply. This Condition will only apply during the following two scenarios:

1) Motor driven AFW pump 2 OPERABLE, motor driven AFW pump 3 inoperable, and steam supply from SG 2 inoperable, or

2) Motor driven AFW pump 2 inoperable, motor driven AFW pump 3 OPERABLE, and steam supply from SG 3 inoperable.

This ensures that if a FLB were to occur affecting the OPERABLE motor driven AFW pump, the turbine driven AFW pump would still be capable of providing AFW to two intact steam generators. If a MSLB were to occur on the SG feeding the remaining OPERABLE steam supply to the turbine driven AFW pump, the OPERABLE motor driven AFW pump would still be capable of providing AFW to two intact steam generators.

If motor driven AFW pump 2 and the steam supply from SG 2 are inoperable, or if motor driven AFW pump 3 and the steam supply from SG 3 are inoperable, then Condition E for two inoperable AFW pumps applies.

The 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> Completion Time is reasonable based on the fact that the remaining motor driven AFW train is capable of providing 100 % of the AFW flow requirements, and the low probability of an event occurring that would challenge the AFW system.

In MODE 4 with two AFW trains inoperable, operation is allowed to continue because only one motor driven pump AFW train is required in accordance with the Note that modifies the LCO. Although not required, the unit may continue to cool down and initiate RHR.

(continued)

DIABLO CANYON - UNITS 1 & 2 Revision 6