ML18038A899
| ML18038A899 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 09/08/1994 |
| From: | Salas P TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-94-02, GL-94-2, NUDOCS 9409160200 | |
| Download: ML18038A899 (19) | |
Text
PR.ICBM.I EY' CCELERATED RIDS PROCESSING)
REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
A'CCESSION NBR:9409160200 DOC.DATE: 94/09/08 NOTARIZED: YES FACIL:50-259 Browns Ferry Nuclear Power Station, Unit 1, Tennessee 50-260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee 50-296 Browns Ferry Nuclear Power Station, Unit 3, Tennessee
'AUTH.NAME AUTHOR AFFILIATION SALAS,P.
Tennessee Valley Authority RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
SUBJECT:
Responds to GL 94-02, "Long-Term Solutions
& Upgrade of Interim Operating Recommendations for Thermal-Hydraulic Instabilities in BWRs."
DISTRIBUTION CODE:
A001D COPIES RECEIVED:LTR ENCL SIZE:
TITLE: OR Submittal:
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0 RECIPIENT ID CODE/NAME PD2-4 WILLIAMS,J.
INTERNAL: ACRS NRR/DRCH/HICB NRR/DSSA/SPLB
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t NOTE TO ALL"RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE iVASTE!CONTACTTIIE DOCUMENTCONTROL DESK, ROOM PI-37 (EXT. 504-2083 ) TO ELIAff. JATE YOUR NAME FROif DISTRIBUTIONLISTS I'OR DOCL'MENTS YOU DON"I'LED!
TOTAL NUMBER OF COPIES REQUIRED:
LTTR 21 ENCL 19
Tennessee Valley Authority, Post Office Box 2000, Oecatur, Alabama 36609 Sept:ember 8,
1994 U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555 Gentlemen:
In the Matter Of Tennessee Valley Authority Docket Nos.
50-259 50-260 50-296 BROWNS FERRY NUCLEAR PLANT (BFN) - UNITS 1q 2i AND 3
RESPONSE
TO NRC GENERIC LETTER (GL) 94 LONG-TERM SOLUTIONS AND UPGRADE OF INTERIM OPERATING RECOMMENDATIONS FOR THERMAL-HYDRAULICINSTABILITZES IN BOILING WATER REACTORS This letter provides TVA's response to the requested actions of NRC GL 94-02.
In Action 1, NRC requested that TVA review BFN operating procedures and operator training programs, and modify them as appropriate, to strengthen administrative provisions intended to avoid power oscillations or to detect and suppress the oscillations if they occur.
In Action 2, NRC requested that TVA develop and submit. a plan for implementing a long-term solution for stability.
In summary, TVA plans to modify, where necessary, BFN operating procedures and training programs to make them consistent with or more conservative than the Boiling Water Reactor Owners Group (BWROG) Guide'lines for Stability Interim Corrective Action (transmitted to NRC by BWROG letter dated June 6,
1994).
TVA expects to complete any procedural or training program upgrades, and conduct necessary
- training, by December 9,
1994.
9409ib0200 940908 F'DR AD~CK 0~0 p
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~ U.S. Nuclear Regulatory Commission Page 2
September 8,
1994 TVA has also elected to proceed with a long-term solution designated as Option III in NEDO-31960 and NED0-31960, Supplement 1,
"BWR Owners'roup Long-Term Stability Solutions Licensing Methodology."
TVA will implement the Option III methodology as an integrated part of an advanced digital power range neutron monitoring (PRNM) upgrade using General Electric's (GE) Nuclear Measurement,
- Analysis, and Control (NUMAC) equipment.
P At this time, TVA intends to have the PRNM upgrade with the Option IIItrip in the "indicate only" mode installed in Unit 2 during the Cycle 8 refueling outage, currently scheduled for April 1996.
Pending one cycle of operation for testing, TVA intends to enable the stability trip prior to startup from the Cycle 9 refueling outage.
- However, TVA's implementation schedule is contingent upon NRC acceptance of the planned BWROG submittal on methodology and the GE generic submittal on the implementing hardware and software design.
The basis for this 'implementation schedule is two fold.
First, installation of the PRNM upgrade on Unit 2 should not interfere with Unit 3 restart activities.
Since Unit 3 restart may require use of the simulator with the existing average power range monitor (APRM) configuration, Unit 2 cannot be upgraded until Unit 3 has restarted.
- Second, TVA currently plans to implement future modifications first on BFN Unit 2, followed by Unit 3, and finally by Unit 1.
This sequence is consistent with the Unit 1 and 3 restart sequences from their extended outages.
This sequence will also allow TVA to implement the neutron monitoring system upgrade in a consistent, controlled,
'and logical manner.
Following NRC issuance of a safety evaluation report (SER) approving the generic NUMAC/PRNM topical report, TVA will confirm its implementation schedule for the stability long-term solution for BFN Units 1, 2, and 3.
TVA expects to confirm its implementation schedule within 30 days of NRC issuance of the SER.
i l
U.S. Nuclear Regulatory Commission Page 3
September 8,
1994 Enclosure 1 contains additional information on TVA's actions in response to GL 94-02.
Enclosure 2 provides a schedule for the generic design and licensing activities for the Option III methodology and PRNM upgrade.
Enclosure 3 provides a
schedule of BFN-unique activities for implementation of Option III with the PRNM upgrade.
Enclosure 4 lists the commitments made in this response.
If you have any questions regarding this submittal, please contact me at (205) 729-2636.
Sincerely, Pe q Salas Manager of Site Licensing Subscribe/
and sworn t be ore me this $44 day of 1994.
Notary Public
<+i.W~~@R) ~o3 1M'y Commission Expires Enclosures cc:
See page 4
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U.S. Nuclear Regulatory Commission Page 4
September 8,
1994 Enclosure cc (Enclosure):
Mr. Mark S. Lesser, Section Chief U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 NRC Resident Inspector Browns Ferry Nuclear Plant Route 12, Box 637
- Athens, Alabama 35611 Mr. J.
F. Williams, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852
l I
ENCLOSURE 1
TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNITS 1, 2, and 3
NRC GENERIC LETTER (GL) 94-02
RESPONSE
TO REQUESTED ACTIONS 1 AND 2 X ~
RESPONSE
TO RE UESTED ACTXON 1 INTERIM CORRECTXVE ACTIONS TVA has implemented and incorporated into BFN Units 1,
2, and 3 Technical Specifications (TS) the Interim Corrective Actions (ICAs) specified in NRC Bulletin 88-07, Supplement 1.
In addition, TVA has been a
part of the Boiling Water Reactor Owners Group (BWROG) effort to develop improved guidelines for the ICAs to better address startup and low power maneuvering conditions.
A copy of the Improved BWROG Guidelines for Stability Interim Corrective Action was provided to NRC in Reference 1.
The Improved BWROG Guidelines are consistent with, but more restrictive than, the ICAs specified in NRC Bulletin 88-07, Supplement 1.
The original ICAs specified regions based on stability tests and events known at, the time.
Subsequent work identified a sensitivity to reactor power shape and/or feedwater temperature conditions.
To respond to this new information, the Improved BWROG Guidelines incorporate an expanded stability region and power distribution control definition to strengthen the oscillation prevention feature.
This, in conjunction with the detection and suppression provisions of the Improved BWROG Guidelines, provides a higher degree of protection against unacceptable power oscillations.
It is TVA's understanding that the NRC will, based on a review of an advanced copy of the interim BWROG guidelines (Reference 2), accept the interim BWROG guidelines as an adequate response to Requested Actions 1.a and 1.b.
B.
Action Planned - Interim Corrective Actions TVA plans to modify, where necessary, BFN operating procedures and training programs to make them consistent with, or more conservative than, the
J
interim BWROG guidelines.
TVA expects to complete any procedural or training program upgrades, and conduct necessary
- training, by December 9,
1994.
TVA will notify NRC within 30 days of completion of these actions.
TVA has modified the BFN power/flow map to add a
Region III, Controlled Entry Region, with appropriate controls to conservatively prohibit any intentional entry into this region.
Should this region be
- entered, BFN procedures require taking immediate action to exit this region.
Additionally, since BFN Units 1, 2, and 3 are not currently licensed to operate at the maximum extended load line, TVA will not include the zone above the 1084 rod line in the Exit Region discussed in the interim BWROG guidelines.
TVA currently has TS requirements which specify a
manual scram if Region I is entered, and immediate action to exit Region II if Region II is entered.
TVA does not plan to modify the BFN TS because the operating procedure and training program modifications necessary to implement the ICAs are intended for use only until the stability long-term solution is implemented, and can be accommodated within the currently applicable TS.
II.
RESPONSE
TO RE UESTED ACTION 2 LONG-TERM SOLUTION The NRC requirement for stability long-term corrective actions to ensure compliance with General Design Criteria 10 and 12 of 10 CFR 50 was originally presented in NRC Bulletin 88-07, Supplement 1.
The Bulletin acknowledged that NRC was working with the BWROG to develop generic approaches for resolving this issue.
The resulting BWROG effort led to the solution concepts and supporting methodology described in NEDO-31960 and NED0-31960, Supplement 1,
"BWR Owners'roup Long-Term Stability Solutions Licensing Methodology."
In Reference 3,
NRC documented its acceptance of the BWROG solution concepts and supporting methodology.
B.
Action Planned - Lon -Term Solution Based on the technical progress that has been made on the BWROG stability program, and the degree of NRC acceptance of various solution concepts, TVA has formulated plans to implement a stability long-term solution.
TVA has elected to proceed with the
solution designated as Option III, which introduces new plant hardware/software to provide early detection of coupled neutronic/thermal-hydraulic instabilities and to initiate an appropriate mitigating action.
To complete this activity, TVA is participating with other utilities under a
BWROG program to finalize the supporting Option III methodology.
TVA plans to contract with General Electric (GE) to develop the hardware/software design and deliver the final product.
Recommendations for associated TS changes will be provided as part of the BWROG methodology program.
TVA will incorporate these TS changes as appropriate.
Any proposed changes to the BFN TS will also require deletion of the existing TS requirements for stability (TS 3.5.M).
The new hardware will implement the Option III methodology as an integrated part of an advanced digital power range neutron monitoring (PRNM) upgrade using GE Nuclear Measurement,
- Analysis, and Control (NUMAC) equipment.
This integrated implementation approach will improve overall PRNM performance and will provide a better overall solution for the stability trip function since it will improve LPRM signal processing and minimize the risk of creating new problems at the stability trip hardware/PRNM interface.
Implementation of the stability long-term solution is contingent upon NRC acceptance of the planned BWROG submittal on methodology and the TVA/GE generic submittal on the implementing hardware and software design.
The schedule for the generic design and licensing activities is provided in Enclosure 2.
Assuming the joint development activities and NRC acceptance are completed as scheduled, TVA intends to install the PRNM upgrade, with the Option IIItrip in the "indicate only" mode, in Unit 2 during the Cycle 8 refueling outage, currently scheduled for April 1996 TVA will be developing specific plans to monitor and evaluate the Option III trip performance in Unit 2 for one operating cycle prior to activation of the automatic trip.
Subject to successful identification and implementation of any required modifications, TVA intends to have the automatic stability trip
'Unit 2 will be TVA's lead plant for installation and testing of the PRNM upgrade with the Option III trip.
operational for Unit 2 prior to startup following the Cycle 9 refueling outage.
TVA will confirm this installation schedule following issuance of the NRC safety evaluation report (SER) for the generic topical reports.
For Unit 3, TVA currently plans to install the Unit 3 NUMAC PRNM upgrade following installation of the Unit 2
NUMAC PRNM upgrade.
TVA currently has no firm installation schedule for the Unit 1 NUMAC PRNM upgrade with the stability trip.
TVA will confirm its plans for Units 1 and 3 following issuance of the NRC SER.
IXI REFERENCES 1.
BWROG letter to NRC dated June 6,
- 1994, "BWR Owners'roup Guidelines for Stability Interim Corrective Action" 2.
BWROG letter to NRC dated April 4,
- 1994, "BWR Owners'roup Improved Guidelines for Stability Interim Corrective Actions" 3.
NRC letter to BWROG dated July 12,
- 1993, "Acceptance for Referencing of Topical Reports NEDO-31960 and NEDO 31960 Supplement 1,
'BWR Owners Group Long-Term Stability Solutions Licensing Methodology'TAC No.
M75928)
E1-4
ENCLOSURE 2
TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNITS 1, 2, and 3
RESPONSE
TO NRC GENERIC LETTER 94-02 GENERIC DESIGN
& LICENSING ACTIVITIES (OPTION ZZZ PLUS PRNM UPGRADE)
Date
~Activit 1993 NRC Approval of BWROG Long Term Stability Solution Licensing Methodology, NEDO-31960 and NEDO-31960, Supplement 1 (Complete) 1993 Initiate NUMAC PRNM Equipment Design Work (GE)
(Complete) 2Q94 2Q94 Deliver first NUMAC PRNM (without stability option) to non-US BWR (GE)
(Complete)
Initiate Design Work to Incorporate Option III Into NUMAC PRNM Architecture (GE)
(Complete) 3Q94 Select Lead Plant for NUMAC PRNM with Option III (Complete) 9/94 4Q94 1Q95 Meet With NRC to Review Overall Licensing Plan and Review Key Issues (GE and Utilities) (Scheduled)
Meet With NRC to Review Technical Issues and Resolution Status Submit NUMAC PRNM with Option III & 2 out of 4 Trip Logic Generic Topical Report (Hardware/Software Implementation and Generic Issues)
(GE)
. 1Q95 Submit Detect and Suppress Topical Report (BWROG) 2Q95 Lead Plant System Design Complete 2Q95 Lead Plant Hardware Fabrication Complete 3Q95 NRC Approval (SER) of Generic NUMAC PRNM Topical Report 4Q95 NRC Approval (SER) of BWROG Detect
& Suppress Topical Report 4Q95 Option III Ready for Installation at Lead Plant
ENCLOSURE 3
TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNITS 1, 2, and 3
RESPONSE
TO NRC GENERIC LETTER 94-02 BFN UNIQUE ACTIVITIES (OPT10N ZZZ PLUS PRNM UPGRADE)
Date
~Activit 3Q95 Confirm Schedule for Implementation of NUMAC PRNM Upgrade with Option III Stability Monitor (OPRM) Following NRC Approval (SER) of Generic NUMAC PRNM Topical Report 3Q95 Submit Units 1, 2, and 3 Proposed Technical Specification (TS)
Amendment for NUMAC PRNM Upgrade 4/96 NRC SER for Units 1, 2, and 3
TS Amendment for NUMAC PRNM Upgrade (Prior to Cycle 8 Refueling Outage Scheduled to Start 4/96) 4/96 Install Unit, 2 NUMAC PRNM Upgrade with OPRM in Alarm Mode (Stability Trip Disabled) 6/96 Submit Units 1, 2,
and 3
OPRM Proposed TS Amendment 9/97 NRC SER for Units 1, 2, and 3
OPRM TS Amendment (Prior to Unit 2 Cycle 9 Refueling Outage Scheduled to Start 10/97) 4Q97 Activate Unit 2 OPRM RPS Trip Function Prior to Startup From Cycle 9 Refueling Outage 4Q97 Install Unit 3 NUMAC PRNM Upgrade With OPRM RPS Trip Function TBD Install Unit 1 NUMAC PRNM Upgrade With OPRM RPS Trip Function
ENCLOSURE 4
TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNITS 1, 2, and 3
RESPONSE
TO NRC GENERIC LETTER (GL) 94-02 LIST OF COMMITMENTS 2 ~
3 ~
4 ~
5.
6.
7.
TVA will modify, where necessary, BFN operating procedures and BFN training programs to make them consistent. with, or more conservative than, the interim Boiling Water Reactor Owners Group (BWROG) guidelines.
These guidelines were transmitted to NRC by a BWROG letter dated June 6,
1994.
TVA expects to complete any procedure changes and training program upgrades, and conduct necessary
- training, by December 9,
1994.
TVA will notify NRC within 30 days of completion of the procedural and training actions discussed above.
TVA will implement the BWROG Option III methodology for the stability long-term solution at BFN Units 1, 2, and 3.
TVA will notify the NRC within 30 days of implementation of the stability long-term solution for Unit 1.
TVA will notify the NRC within 30 days of implementation of the stability long-term solution for Unit 2.
TVA will notify the NRC within 30 days of implementation of the stability long-term solution for Unit 3.
Following NRC issuance of a safety evaluation report (SER) approving the generic NUMAC/PRNM topical report, TVA will confirm its installation schedule for the stability long-term solution for BFN Units 1, 2, and 3.
TVA expects to confirm its installation schedule within 30 days of NRC issuance of the SER.
0
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