ML20216G834

Application for Amend to TS 4.5.2.b & Associated Bases to Licenses NPF-37,NPF-66,NPF-72 & NPF-77,respectively,to Bring Byron Unit 1 & Braidwood Unit 1 Requirement in Conformance W/Unit 2 Requirements Approved by NRC in

ML20216G834
Person / Time
Site:	Byron, Braidwood
Issue date:	09/08/1997
From:	Graesser K COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20216G841	List: ML20216G834 ML20216G854
References
BYRON-97-0202, BYRON-97-202, NUDOCS 9709160061
Download: ML20216G834 (8)

Text

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'ItlHi% D iSeit September 8,1997 LTR: ilYRON 97-0202 FILE: 2.01.0301 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washin;' ton D C. 20555 0001

Subject:

Application for Amendment to Appendix A, Technical Specifications, to Facility Operating Licenses:

Ilyron Nuclear Power Station, Units 1 & 2 Facility Operating Licenses NPF 37 and NPF 66 NRClhicket Nos 50-454 and 50-415 Braidwood Nuclear Power Station, Units I & 2 Facility Operating Licenses NPF 72 and NPF 77 NRClktsketNos_50 456 and 50-452

" Emergency Core Cooling System Venting"

References:

See Attached in Reference 1, Commonwealth Edison (Comed) requested an exigent amendment for Ilyron Units I and 2 and Braidwood Unit 2. The proposed change affected Technical Specification 4.5.2 b with respect to venting of Emergency Core Cooling System (ECCS) pump casings and discharge piping high points outside of containment. In Reference 2, Comed requested that the exigent amendment request in Reference I be approved as an emergency change for Byron Unit I because an emergency situation arose that would have prevented stattup of Unit 1, The emergency change was approved in Reference 3. In Reference 4, the NRC transmitted a request for additional information (RAl) concerning the exigent request for Byron Unit 2 and Braidwood Unit 2. ComlL! responded to the Reference 4 questions in Reference 5 Comed revised the exigent Technical Specification submittal for Byron Unit 2 and Braidwood Unit 2 (Reference 6) based on discussions with the NRC staff and Comed's RAI response (Reference 5). This revised submittal was approved in Reference 7.

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1 IlYRON 97 0202 September 8,1997 Page 2 Comed is requesting a change to Technical Specification 4.5 2.b and associated bases to bring the flyton Unit I and Braidwood Unit I requirement in conformance with the Unit 2 requirements approved by NRC in Reference 7. The proposed changes are described in detailin Attachment A. The revised Technical Specification changes are provided in Attachments B 1 and 112 for Byron and Braidwood, respectively. Attachment C provides the Evaluation of Significant llazards Consideration and Attachment D provides the Environmental Assessment.

Please direct any questions to Marcia Lesniak, Nuclear Licensing Administrator, at (630) 663-6484.

I aflirm that the content of this transmittal is true and correct to the best of my knowledge, information and belief.

Sincerely, 4

M K. L. Graesser Site Vice President 11yron Nuclear Power Station KLF/L71rp Attachments cc:

A.II. lleach, Regional Administrator - kill S.D. Burgess, Senior Resident inspecte - Byron C F. Phillips, Senior Resident Inspector - Braidwood G.F Dick, Jr., Project Manager - NRR Oflice of Nuclear Safety - IDNS Signed bgfore me this IO

day, of

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.1997, L ^ =Q^g,, - ~ ^ -R by Pc a w l of gg Notary Pubhc 1 u,c

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l llYRON 97-0202 Sept' mber 8,1997 e

Page 3 RtfrLt0In 1.

T.J. Tulon (Comed) letter to the United States Nuclear Regulatory Commission (NRC) Document Control Desk," Application for Exigent Amendment to Appendix A, Technical Specifications, for Facility Operating License NPF 37, NPF 66, and NPF-77," dated hiay 24,1997.

2.

K. L. Graesser (Comed) letter to the NRC Document Control Desk," Supplement to Application for Exigent Amendment to Facility Operating License NPF-37,"

dated May 31,1997.

3.

R. A. Capra (NRC letter to 1. hi. Johnson (Comed), " Issuance of Emergency Amendment (TAC NO. h198781)," dated June 1,1997.

4.

G. F. Dick, Jr. (NRC) letter to I. M. Johnson (Comed), " Request for additional Information Regarding Emergency Core Cooling System Venting - 11raidwood Station, Unit 2 and Ilyron Station, Unit 2 (TAC Nos. hi98780 and hi98782),"

dated June 6,1997.

5.

J. Ilosmer (Comed) letter to NRC Document Contr01 Desk," Request for Additional Information Response for Emergency Core Cooling System Venting Surveillance," dated June 20,1997.

6.

K L. Graesser (Comed) letter to NRC Document Control Desk," Supplement to the Application for Exigent Amendment Request for Appendix A, Technical Specifications, to Facility Operating Licenses NPF-66 and NPF-77," dated June 24,1997.

7.

R. R. Assa, (NRC) letter to 1. M. Johnson, " Issuance of Amendments (TAC Nos.

M98782 and M98780)," dated August 13,1997.

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ATTACllMENT A DESCRIPTION AND SAFETY ANALYSIS OF PROPOSED CilANGES TO APPENDIX A, TECilNICAL SPECIFICATIONS, OF FACILITY OPERATING LICENSES NPF 37, NPF 66, NPF 72, and NPF.77 A.

DESCRIPTION OF Tile PROPOSED CilANGE Commonwealth Edison (Comed) proposes to revise Byron and Braidwood Technical Specification (TS) 4.5 2 b an<l associated bases as they relate to the requirement to vent the Emergency Core Cooling System (ECCS) pump casings and discharge piping high points outside containment. The change will revise the Unit I requirement for ultrasonic examinations every 31 days to also include ultrasonic examination of the piping at the ICV 206 valve for Byron (ICV 207 for Braidwood)if the IB Chemical Volume and Control (CV) pump is idle. These changes are required to align the surveillance requirements for Unit I with those of Unit 2. In 4

~

addition, the condition that the Unit I requirements will be applicable only until the end of the a

current cycle is deleted consistent with the Unit 2 requirements.

These proposed changes are discussed in detail in Section E of this attachment The afTected TS and bases pages showing the proposed revisions are included in Attachments B-1 and B 2 of this request, for Byron and Braidwood, respectively.

1 H.

DESCRIPTION OF Tile CURRENT REQUIREMENT TS 4.5.2.b.1 requires venting of the idle Residual lleat Removal (Ril) and Safety injection (SI) pump casings and discharge piping high point vent valves outside of containment once per 31 days In addition, TS 4.5.2.b.3 requires that the Unit 1 Chemical Volume and Control (CV)

System be veri 0ed full of water every 31 days by ultrasonic (UT) examination of the discharge portion of the idle CV pump up to the discharge check valve and the stagnant portion of the piping upstream of the IS18801 A and B valves at the IS1045 valve. The Unit 2 CV System is verined full of water every 31 days by the same UT examinations as Unit I with the addition of UT examination of the piping at the 2CV206 valve if the 2B CV pump is idle.

n:\\byrbwd\\newvent. doc Page 1 of 5 Attachment A

4 C,

,HASES FOR Tile CURRENT REQUIREMENT The bases for the current requirement are to provide confidence that the ECCS piping is filled with water to preclude voiding that could result in unacceptable dynamic loading from water hammer. This helps ensure that the ECCS systems are capable of performing their design function.

l D.

NEED FOR REVISION OF Tile REQUIREMENT Comed reviewed the CV system piping as required by a Request for Additional Information (RAI) dated June 6,1997 associated with the Unit 2 TS change and discussed the results with the NRC StafT. An intermediate high point location with vent valve CV206 (CV207 for Braidwood Unit 1)is located in a section of the CV discharge piping which, dependent upon system operation, could be stagnant. This occurs when the B train of the CV system is idle. A requirement to UT the piping at this location when the B CV pump is idle provides additional confidence that the CV discharge piping is full of water. The wording of the current Unit i TS does not include the UT examination of this segment of piping, although these examinations are currently being performed. Therefore, a change to the Unit 1 TS is needed to incorporate this additional UT examination requirement, consistent with the Unit 2 requirement.

The current Unit i TS limits applicability of TS Surveillance Requirement 4.5.2.b only through the current cycle for Byron and Braidwood, cycle 8 and cycle 7, respectively. Based on communication with the NRC Staff, it has been determined that there is no time dependency that requires a cycle restriction associated with this surveillance. Therefore, a change to the Unit 1 TS is needed to remove the cycle restriction.

E, DESCRIPTION OF Tile REVISED REQUIREMENT Unit 1 TS 4.5.2.b will be revised to remove the cycle-specific limitation. Unit 1 TS 4.5.2.b.3 will be revised to add the requirement for UT examination of the piping at the CV206 valve (CV207 for Braidivood Unit 1) for an idle B CV pump every 31 days. Eh these changes, the need for reparate Unit I and Unit 2 Surveillance Requirements will be eliminated. Deletion of unit designators on vslve and pump numbers will allow bo:h Units to be covered by the same requirement. Therefore, the 3/4 5-4a and 3/4 5-4b pages will be deleted and only a single page V4 5-4, encompassing both units, will reinain.

The Unit i bases discussion will be cieleted and the Unit 2 discussion revised to encompass both units.

nnbyrbwd\\newvent. doc Page 2 of 5 Attachment A j

,F,

,HASES FOR Tile REVISED REQUIREMENT The bases for the revised requirement are unchanged from that of the current reqairement. The purpose of venting the non-operating Si and Ril systems is to ensure that the piping is full of water and to provide confidence that water hammer which could result from voiding would not result in unacceptable dynarnic loads Those systems which will not be manually vented are in communication with an operating system and subject to system flow. For the CV system, the non-active portion of piping upstream of the injection line isolation valves is subjected to CV pump discharge pressure of approximately 2500 psia. The pumps are designed and installed to be virtually self-venting, and are not provided with casing vent valves. The design of the pump places the suction and discharge piping at the top of the pump casing The CV suction piping is in communication with either the Refueling Water Storagc Tank (RWST) or the Volume Control Tank (VCT). Both of these sources provide a net positive suction pressure for the pumps.

For the RH system it. operation during shutdown cooling, the piping that is excluded from manual venting is subjected to a pressure of approximately 360 psia and flows that vary from approximately 1000 gpm to 3000 gpm. The operating RH pump and piping are not subject to gas accumulation under these conditions.

UT examination of portions of the CV piping will be subject to a "go-no go" acceptance criterion. If the line is determined to be water solid, the Surveillance Requirement will be met.

If the UT examination reveals that the line is not water solid, the appropriate systems, structures, or components will be declared inoperable and associated actions taken.

The design of the CV pumps is such that significant air does not collect in the pumps, whether they are running or not. The suction and ducharge lines are on the top of the CV pumps and the internal cavities in the pump are small enough that significant air accumulation in the pump casings would not occur. In addition, there is a mini-flow recirculation line on the discharge side of each CV pump. For the running CV pump, any air in the discharge piping is expected to either recirculate to the VCT suction or stay in solution and pass through the CV injection lines to the reactor vessel.

Even though Comed considers it highly unlikely that significant air bubbles would exist anywhere in the CV system piping, there is some potential that small amounts of air could accumulate on the upstream side of check valves that protect the standby CV pump from charging header backpressure. However, as documented in the requests for Operating License Amendments 47 for Byron and 36 for Braidwood, Comed previously evaluated the consequences of air in the ECCS system piping. Amendments 47 (Byron) and 36 (Braidwood) were approved by NRC in a letter June 22,1992. The associated Safety Evaluation Report (SER) did not provide specific approval of the water hammer analysis submitted by Comed and i~licated that " calculations and analytical methods used in determining the effects of water hammer are uncertain in nature due to computer code limitations."

nAbyrbwd\\newvent. doc Page 3 of 5 Attachment A

4 Comed recently reviewed related calculations. A review of the potentially affected piping was

'perforrhed Th VCT rp ovides the net positive suction head for the CV pumps. The VCT is e

located at elevation 426 feet. The VCT level is typically maintained between 37% level (approximate elevation 431 feet) and 55% (approximate elevation 433 feet). In addition, the VCT is maintained at a minimum of 15 psig for reactor coolant pump seal backpressure. This is equivalent to 34 fee of water at standard temperature and pressure.

The elevation of the CV pump discharge check valves is at approximately elevation 370 feet.

Tue elevation of the highest point of the discharge piping outside containment is approximately 397 feet. Thus, based on static pressures on the suction side of the CV pumps, air bubbles in the discharge piping of the CV system are unlikely. However, if an air bubble became entrapped in the discharge piping, the discharge piping woud be subjected to transient loads during system operation. The air bubble would act as a cusW,, traveling along the piping. The air water inte face would impart an impact load in the piping at each change in direction The affected piping is safety related and is seismically supported.

A review of the Ril and SI systems was previously performed in support of Amendments 47 (Byron) and 36 (Braidwood) to address the potential formation of air bubbles in ECCS piping.

Although a static evaluation concluded that the analyzed piping would be water solid, a study was performed to evaluate air bubbles in 2-inch and 8-inch diameter Ril piping. The study concluded that the fluid transient loads, isociated with a water-solid condition in the 2-inch line were small. Reevaluating this line with an air bubble did not increase the Guid transient loads t

significantly. The 8-inch diameter line experienced considerably larger fluid transient loads.

Thus, the 8 inch line was considered the limiting case in this study. An evaluation of the 8-inch line with a 77-foot long air bubble (approx.19.5 ft') concluded that the fluid transient loads were less than the capacities of the supports. An evaluation for a totally voided RH discharge line aise yielded fluid transient loads less than the support capacities. The study concluded that the presence of an air bubble would not create a design concern.

The subject CV piping is comprised of 4-inch diameter schedule 160 stainless steel piping. A typical length of piping between the CV pu,mp discharge and the containment isolation valves (S18801 valves) is 160 feet (approx,10.5 fl ). The effects of a bubble in the CV discharge piping are expected to be enveloped by the evaluation of the 8-inch line. The integrity of the 4-inch schedule 160 piping would not be challenged by these loads.

Finally, Byron and Braidwood have performed Ultrasonic Testing (UT) inspections of the CV piping system. Specifically, the piping on the discharge side of the standby CV pump up to the downstream check valves for both units was UT inspected along with the stagnant piping around the S1045 valves and the piping at the CV206 (CV207 for Braidwood Unit 1) valve when the B CV pump was idle. No air voids were identified in these sections of piping.

n:\\byrbwd\\newvent. doc Page 4 of 5 Attachment A

,G.

-,lMPACT OF THE PROPOSED CHANGE

-The changes proposed in this request will provide continued confidence that unacceptable accumulations of gases will not occur, and will align the surveillance requirements with the design configuration of the ECCS piping. Additionally, the changes provide common requirements for Unit I and Unit 2.

II.

SCllEDULE REQUIREMENTS The current Byron Unit I requirement expires at the end of cycle 8, which is currently scheduled for November 1997.1 The current Braidwood Unit I requirement expires at the end of cycle 7

" which is currently scheduled for September 1998. Therefore, Comed requests that these proposed changes be approved prior to December 19,1997 in order to support cycle 9 startup of Byron Unit I following the next refueling outage (BIR08).

n:\\byrbwd\\newvent. doc Page 5 of 5 Attachment A I

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