TSTF-07-21, Response to NRC Request for Additional Information Regarding TSTF-431, Revision 1, Change in Technical Specifications End States (BAW-2441), Dated May 3, 2007

Response to NRC Request for Additional Information Regarding TSTF-431, Revision 1, Change in Technical Specifications End States (BAW-2441), Dated May 3, 2007

ML071910061
Person / Time
Site:	Technical Specifications Task Force
Issue date:	07/09/2007
From:	Gambrell R, Joseph Messina, Millar D, Yates B Babcock & Wilcox, BWR Owners Group, Combustion Engineering, PWR Owners Group, Technical Specifications Task Force
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
BAW-2441, TSTF-07-21
Download: ML071910061 (6)

Text

TECHNICAL SPECIFICATIONS TASK FORCE TSTF A JOINT OWNERS GROUP ACTIVITY July 9, 2007 TSTF-07-21 PROJ0753 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001

SUBJECT:

Response to NRC Request for Additional Information Regarding TSTF-431, Revision 1, "Change in Technical Specifications End States (BAW-2441)," dated May 3, 2007.

REFERENCE:

Letter from Timothy Kobetz (NRC) to the Technical Specifications Task Force, "Request for Additional Information Regarding TSTF-431, Revision 1,

'Change in Technical Specifications End States (BAW-2441)'," dated May 3, 2007.

Dear Sir or Madam:

In the referenced letter, the NRC provided a Request for Additional Information (RAI) regarding TSTF-431, Revision 1, "Change in Technical Specifications End States (BAW-2441)." This letter responds to the NRC's referenced request.

The NRC granted a fee exemption for the review of TSTF-431 as documented in the letter from Timothy Kobetz (NRC) to the TSTF dated December 5, 2006.

The TSTF requests that the Traveler be made available under the Consolidated Line Item Improvement Process.

11921 Rockville Pike, Suite 100, Rockville, MD 20852 Phone: 301-984-4400, Fax: 301-984-7600 Email: tstf@excelservices.com Administered by EXCEL Services Corporation

TSTF 07-21 July 9, 2007 Page 2 Should you have any questions, please do not hesitate to contact us.

Bert Yates (PWROG/W) John Messina (BWROG)

Dana Millar (PWROG/CE) Reene' Gambrell (PWROG/B&W)

Enclosure cc: Tim Kobetz, Technical Specifications Branch, NRC Ross Telson, Technical Specifications Branch, NRC Matthew Hamm, Technical Specifications Branch, NRC

Technical Specification Task Force (TSTF) Response to NRC Request for Additional Information Regarding TSTF-431, Revision 1, "Change in Technical Specifications End States (BAW-2441)," dated May 3, 2007 The following is the Technical Specification Task Force (TSTF) response to NRCs May 3, 2007, letter requesting the following information to complete the review of TSTF-431.

1. Question:

Discuss how TSTF-431 implements the condition of approved topical report for LCO 3.4.15 regarding the availability and use of alternative RCS leakage detection capabilities.

Background:

In Section 4.4.4 of the approved topical report BAW-2441-A Rev. 2, the basis for the proposed change affecting Technical Specification (TS) Limiting Condition of Operation (LCO) 3.4.15 Reactor Coolant System (RCS) Leakage Detection, identifies the availability of additional instruments to provide secondary indication of a loss of coolant accident. TSTF-431, Rev. 1 does not address this requirement. LCO 3.4.15 currently includes action requirements (A.1, B.1.1, and B.1.2) to use alternative leakage detection instrumentation and containment sampling until the LCO action is exited, either by restoration of the inoperable leakage detection instruments or by exiting the mode of applicability of the LCO. The proposed change in BAW-2441-A Rev. 2 to establish a Mode 4 endstate identified the availability of the alternative instrumentation as a basis for acceptability. This requirement of the topical report should be implemented in TSTF-431 by revising the TS actions to include a requirement to continue implementing alternative RCS leakage detection actions while the plant remains in Mode 4.

Response

TSTF-431, Rev. 1, modifies Condition C, which states "Required Action and associated Completion Time not met," to require the plant to be in Mode 4 instead of Mode 5. Condition C is only entered when the Required Actions and associated Completion Times of Conditions A or B are not met. As discussed in the "Background" section of the RAI, Required Actions A.1, B.1.1, and B.1.2 require the use of alternate leakage detection instrumentation and containment sampling as discussed in the Topical Report.

When Condition C is entered, the Required Actions of Condition A or B continue to be applicable and must be followed. As a result, the alternate leakage detection instrumentation and containment sampling required by Required Actions A.1, B.1.1, or B.1.2 must be continued while remaining in Mode 4 under the revised Required Action C.2. Therefore, the assumption in the Topical Report is implemented in TSTF-431, Rev. 1.

The Improved Standard Technical Specifications require multiple condition entry which means that all Conditions that apply are entered simultaneously. LCO 3.0.2 states, "Upon discovery of a failure to meet an LCO, the Required Actions of the associated Conditions shall be met, except as provided in LCO 3.0.5 and LCO 3.0.6. If the LCO is met or is no longer applicable prior to expiration of the specified Completion Time(s), completion of the Required Action(s) is not required, unless otherwise stated." Note that the word "Conditions" is plural. All applicable Conditions are entered and may not be exited unless the LCO is met or is no longer applicable. As long as the plant is within the Applicability of the LCO (i.e., Modes 1 - 4), the Required Actions of all the applicable Conditions must be followed.

Technical Specification Task Force (TSTF) Response to NRC Request for Additional Information Regarding TSTF-431, Revision 1, "Change in Technical Specifications End States (BAW-2441)," dated May 3, 2007

2. Question:

Discuss how TSTF-431 implements the conditions of approved topical report for LCO 3.6.1 regarding the availability of the equipment hatch, air locks, and isolation capability.

Background:

In Section 4.4.6 of BAW-2441-A Rev. 2, for TS LCO 3.6.1 Containment, an "assumed limitation" is identified, which requires that the containment equipment hatch remains closed while remaining in Mode 4. TSTF-431 Rev. 1, does not include this restriction.

Further, in Section 4.4.6 of the topical report, part of the basis for the proposed change is the availability of isolation capability for each containment process line, including the containment air locks. The staff review of the LCO requirements for these components determined that the proposed changes of TSTF-431 do not assure availability of isolation capability for all process lines and the airlocks, while LCO 3.6.1 Action B.2 is in effect in Mode 4, which is inconsistent with the stated basis for the proposed change.

The staff notes that similar changes were proposed and approved in CE-NPSD-1186-A Rev. 0, applicable to Combustion Engineering designed nuclear steam supply systems. The implementation of these changes were per approved TSTF-422-A Rev. 1, which did not apply a Mode 4 end state to LCO 3.6.1. This implementation conservatively assured that the topical report assumptions regarding the equipment hatch, air locks, and isolation capability were met while operating in Mode 4. As noted in the TSTF, this implementation approach "retains the topical and safety evaluation restrictions on large leakage while providing the approved flexibility for smaller containment leaks." It is unclear to the staff why the same approach should not apply to TSTF-431.

Response

This RAI addresses three issues:

• Implementation of the assumed limitation on the containment equipment hatch,

• Availability of isolation for all process lines and airlocks, and

• Differences between TSTF-431 and TSTF-422-A.

Implementation of the assumed limitation on containment equipment hatch BAW-2441, Section 4.4.6, the section entitled, "Current and Proposed End State," "Assumed Limitation," states that the proposed end state assumes the equipment hatch will remain closed while in Mode 4. This is a reasonable assumption because licensees would not remove the containment equipment hatch in Mode 4 while relying on the proposed action.

As stated in BAW-2441 and the NRC's Safety Evaluation for BAW-2441, "The primary purpose of entering the end state is to correct the initiating condition and return to power as soon as is practical," and "These assumptions are consistent with typical entries into Mode 4 for short duration repairs, which is the intended use of the TS end state changes." Removal of the Reactor Building equipment hatch is a convoluted, time-consuming process that would not be part of any anticipated short duration repairs necessary to repair the containment and return to power as soon as possible.

Technical Specification Task Force (TSTF) Response to NRC Request for Additional Information Regarding TSTF-431, Revision 1, "Change in Technical Specifications End States (BAW-2441)," dated May 3, 2007 The TSTF-431 Bases of Required Actions B.1 and B.2 state, "The release of stored energy to the Reactor Building in the event of an accident in MODE 4 is substantially less than the energy release assumed due to an accident at power. Therefore, the challenge to containment systems is substantially reduced. The analysis in Reference 4 assumed that the equipment hatch remains closed in MODE 4. Because of the reduction in RCS pressure and temperature in MODE 4, the likelihood of an event is also reduced." The inclusion of this information in the Bases will alert the operator to this assumption in the analysis. Note that these types of assumptions were included in the Bases in TSTF-422-A (See the TSTF-422-A Bases for Specifications 3.5.4 and 3.7.7).

Furthermore, all licensees are committed to implementing actions to reduce shutdown risk consistent with NRC Regulatory Guide 1.182, "Assessing and Managing Risk Before Maintenance Activities at Nuclear Power Plants," which endorses the guidance of NUMARC 93-01, "Industry Guideline for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants," Section 11, as revised in February 2000, as an acceptable approach to meet 10 CFR 50.65(a)(4). Section 11 of NUMARC 93-01 addresses assessing and managing risk in both the operating Modes and during shutdown conditions. The risk assessments described by NUMARC 93-01 for shutdown conditions reference the guidance in NUMARC 91-06, "Guidelines for Industry Actions to Assess Shutdown Management." Section 4.1.1 of NUMARC 91-06, item 3, states, " Containment hatches (equipment and personnel) and other penetrations that communicate with the containment atmosphere (primary or secondary, as appropriate) should either be closed or capable of being closed prior to core boiling following a loss of DHR and should be addressed in procedures." The time to boil in the subject condition (i.e., Mode 4 for short duration repairs) following a loss of DHR is too short to allow reinstallation of the equipment hatch. Therefore, the equipment hatch could not be removed in Mode 4.

Based on these considerations and the inclusion of the Topical Report assumption in the Bases, no changes to TSTF-431 are required.

Availability of isolation for all process lines and airlocks BAW-2441, Section 4.4.6, the section entitled "Basis for Proposed End State," states, "Relative to containment isolation, each process line has redundant isolation that can be implemented manually from the MCR." This assumption will be valid while in the proposed Mode 4 end state with no change to the existing Technical Specifications or to the changes proposed in TSTF-431.

Requirements on the containment penetrations (process lines) and the containment airlock are in Specification 3.6.3, "Containment Isolation Valves, " and Specification 3.6.2, "Containment Air Locks," respectively. If the containment is inoperable for reasons not associated with containment penetrations or the containment airlock, those systems will be Operable and capable of performing their containment isolation function as assumed in the Topical Report.

Technical Specification Task Force (TSTF) Response to NRC Request for Additional Information Regarding TSTF-431, Revision 1, "Change in Technical Specifications End States (BAW-2441)," dated May 3, 2007 If the containment is inoperable due to leakage through a containment airlock greater than La, Specification 3.6.2, Required Action C.2, requires a door to be closed in the affected airlock.

This provides the maximum available isolation capable with the degraded airlock as assumed in the Topical Report.

If the containment is inoperable due to leakage through a containment penetration greater than La, Specification 3.6.3, Required Actions B.1, C.1, and D.1, require the affected penetration flow path to be isolated by use of at least one closed and de-activated automatic valve, closed manual valve, or blind flange. This is consistent with the assumption in the Topical Report.

Therefore, the existing and proposed Technical Specifications will assure availability of isolation capability for all process lines and the airlocks, while LCO 3.6.1 Action B.2 is in effect in Mode 4.

Differences between TSTF-431 and TSTF-422-A BAW-2441, Section 4.4.6, the section entitled "Basis for Proposed End State," states, "Because the energy that can be released to the RB [Reactor Building] when operating in Mode 4 is only a fraction of that associated with a DBA, RB pressure will be only slightly higher should a LOCA occur when operating in Mode 4 as compared to when operating in Mode 5. Also, assuming a RB breach that would cause La at DBA conditions exists (triggering plant shutdown in accordance with this LCO), it would produce RB leakage flow rates considerably less than La when operating in Mode 4 with occurrence of a LOCA" (emphasis added). Note that the BAW-2441 justification explicitly assumes that the containment leakage was greater than La.

The Topical Report for Combustion Engineering plants, CE-NPSD-1186, utilized a different assumption. CE-NPSD-1186, in Sections 5.5.11 (Containment Air Locks) and 5.5.12 (Containment Isolation Valves), assumed that containment leakage was less than La. The NRC's Safety Evaluation for CE-NPSD-1186 stated "only small changes in containment integrity are considered." TSTF-422-A, Attachment 1, "Comparison of CEOG-152, CE-NSPD-1186, and the NRC's July 17, 2001 Safety Evaluation," stated, "These restrictions are inconsistent with LCO 3.6.1, which requires that leakage be less than 1.0 La. Therefore, if the ACTIONS of LCO 3.6.1 are entered, containment leakage must be large (e.g., > 1.0 La). In order to remain consistent with the current application of the specifications, the changes to LCO 3.6.1 are not adopted. If leakage is "large," MODE 5 must be entered in accordance with LCO 3.6.1." Therefore, CE-NPSD-1186 did not assume that containment leakage was greater than La.

Because of this difference in assumptions, it is consistent with the NRC's approval of BAW-2441 to implement the Mode 4 end state for Specification 3.6.1.