ML14176A378
| ML14176A378 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 02/23/1988 |
| From: | Lo R Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8803090350 | |
| Download: ML14176A378 (30) | |
Text
05 UNITED STATES 0
NUCLEAR REGULATORY COMMISSION o
E WASHINGTON, D. C. 20555 Docket No.:
50-261 FEB 2 3 1988 LICENSEE:
Carolina Power & Light Company (CP&L)
FACILITY:
H. B. Robinson 2
SUBJECT:
MEETING
SUMMARY
FOR FEBRUARY 10, 1988 MEETING ON MODIFICATIONS OF THE EMERGENCY ELECTRICAL DISTRIBUTION SYSTEM, H. B. ROBINSON 2 On February 10, 1988, Carolina Power & Light Company (CP&L), the licensee for H. B. Robinson 2 met with NRR and Region II staff to discuss the failure to meet design criteria on single failure of the safety injection (SI) pump emergency electrical distribution system. H. B. Robinson 2 has been shutdown since January 29, 1988, because of this concern. The attendees list and the viewgraphs prepared by CP&L are attached as Enclosures 1 and 2, respectively.
CP&L presented the background of the problem. On January 28, 1988, while review ing plant design for formulating a response to an NRC request regarding the design of the emergency electrical distribution for the.SI system, the licensee found that certain postulated single failures could result in a loss of the capa bility of the SI system to respond adequately to an SI signal.
Failure to meet these single failure scenarios would be a violation of the design criteria under which H. B. Robinson 2 is licensed.
CP&L has tentatively identified a total of seven single failure scenarios under which the SI system could fail to respond adequately to an SI signal.
CP&L has stated that these seven scenarios may require design modifications.
For five of the seven failure scenarios, CP&L has drafted modifications which CP&L believes would remedy the problems (see Enclosure 3, Draft Modifications).
Details of these modifications were discussed with the NRC staff.
For the remaining two scenarios, one of which relates to the original concern that the NRC staff raised on the potential transfer of an electrical fault from one safety train to another, CP&L is evaluating the need for any modifications which will be submitted to the staff if required. CP&L's review identified forty-five other failure scenarios but determined that no modification was necessary. These were not discussed at this meeting.
The meeting concluded with CP&L agreeing to provide the staff its design modifi cation package for review. This package would include the following information related to the emergency electrical distribution to the SI system:
- 1. Results of a detailed review of the design basis, the design basis of the present configuration and the design basis of the modifications to meet the single failure criteria.
- 2. Description of system modifications to meet the design regarding single failure vulnerability.
6803090350 8823 CF ADOCK 05000261 PDR
-2
- 3. Testing program for demonstrating that the modifications would enable the systems to functionally meet the modified design basis.
The NRC staff agreed to review the modification package and witness the testing program to ensure that the modified design bases are met prior to the restart of H. B. Robinson 2.
Ronnie Lo, Project Manager Project Directorate II-1 Division of Reactor Projects I/II
Enclosures:
As stated cc:
The NRC Attendees Sherwood Zimmerman, CP&L DISTRIBUTION:
ee attached sheet PM:PD21:DRPR D:PD21:DRPR RLo EAdensam 2/ /88 2/ /88
Mr. E. E. Utley Carolina Power & Light Company H. B. Robinson 2 cc:
Mr. R. E. Jones, General Counsel Mr. Dayne H. Brown, Chief Carolina Power & Light Company Radiation Protection Branch P. 0. Box 1551 Division of Facility Services Raleigh, North Carolina 27602 Department of Human Resources 701 Barbour Drive Raleigh, North Carolina 27603-2008 Mr. McCuen Morrell, Chairman Darlington County Board of Supervisors Mr. Robert P. Gruber County Courthouse Executive Director Darlington, South Carolina 29535 Public Staff - NCUC P.O. Box 29520 Mr. H. A. Cole Raleigh, North Carolina 27626-0520 Special Deputy Attorney General State of North Carolina P.O. Box 629 Raleigh, North Carolina 27602 Mr. D. E. Hollar Associate General Counsel Carolina Power and Light Company P.O. Box 1551 Raleigh, North Carolina 27602 U.S. Nuclear Regulatory Commission Resident Inspector's Office H. B. Robinson Steam Electric Plant Route 5, Box 413 Hartsville, South Carolina 29550 Regional Administrator, Region II U.S. Nuclear Regulatory Commission Suite 2900 101 Marietta Street Atlanta, Georgia 30303 Mr. R. Morgan General Manager H. B. Robinson Steam Electric Plant Post Office Box 790 Hartsville, South Carolina 29550 Mr. Avery Upchurch, Chairman Triangle J Council of Governments 100 Park Drive Post Office Box 12276 Research Triangle Park, NC 27709
MEETING
SUMMARY
DISTRIBUTION JDocket-50-26-1 NRC PDR Local POR PD21 R/F EAdensam Project Manager Ronnie Lo OGC-B EJordan JPartlow NRC Participants ACRS (10)
NRC PARTICIPANTS Ronnie Lo Don Katze Ken Eccleston Wayne Hodges Ei nor Adensam Dominic Tondi Faust Rosa Peter Kang Paul Fillion Gus Lainas
ENCLOSURE 1 ATTENDEES AT FEBRUARY 10, 1988 MEETING Ronnie Lo NRR/PDII-i Sherwood Zimmerman CP&L-Manager-Nuc.Lic.
Don Katze NRR/DEST/SRXB Ken Eccleston NRR-ADRII-TA Wayne Hodges NRR/DEST/SRXB C. W. Heh?
RII, Dep. Dir. Rr Proj.
E. G. Adensan NRR/DRP/PDII-1 D. Tondi NRR/DEST/SELB Faust Rosa NPR/DEST/SELB Peter J. Kang NRR/DEST/SELB Paul J. Fillion NRC/RII Gus Lainas NRC/NRR/AD RII R. W. Prunty, jr.
CP&L (HBR2 Licensing)
W. J. Flanagan CP&L G. P. Beatty CP&L M. D. Macon CP&L W. W. Price, Jr.
CAROLINA POWER AND LIGHT H. B. ROBINSON SAFEFTY INJECTION PUMP AVAILABILITY WITH A SINGLE RANDOM FAILURE QUESTION
CAROLINA POWER AND LIGHT H.B. ROBINSON TEAM OUTPUT o 5 SCENARIOS CONFIRMED AS SINGLE RANDOM FAILURES AND CORRECTIVE MEASURES IMPLEMENTED
- 1. BREAKER MISALIGNMENT El -
E2 BUS TIE
- 2. TRAIN "A" SAFEGUARDS SEQUENCER INTERLOCK RELAY WITH TRAIN B SAFEGUARD SEQUENCER
- 3. POSTULATED BREAK IN THE INTERNAL WIRING IN THE SAFEGUARDS SEQUENCERS
4*
Carolina Power & Lis Co.
H. B. Robinson Emergency Bus Layout For Safety Injection Pumps offsite offaite power power Bus El Bus E2 Iv)S
)0 1
I I288 178 22_
298 278 29C SIP A SIP C EDG A SIP B EDG B V = Breaker control from Train A battery 0 =Breaker control from Train 8 battery
)
Breaker -- open
- 1)
Breaker - closed EDG - Emergency Diesel Generator SIP -Safety injection Pump
Carolina Power & Lig*Co.
H. B. Robinson Normal Emergency Bus Lineup (Before Jan 28, 1988) offsite offsite power power Bus El Bus E2 Iv 3 I
do 18 288 178 22B 29B 278 tO) )29C SIP A SIP C EDG A SIP B EDG B S=Breaker control from Train A battery O =Breaker control from Train B battery Breaker - open j) Breaker - closed EDG - Emergency Diesel Generator SIP -Safety injection Pump
Carolina Power & Ligh
- o.
H. B. Robinson Normal Emergency Bus Lineup (After Jan 28, 1988) offsite offite power power Bus El Bus E2 I8 288 17B 22V 299 278 I00 29C SIP A SIP C EDG A SIP 8 EDG 8 V =Breaker control from Train A battery O = Breaker control from Train B battery Breaker - open Breaker - closed EDG - Emergency Diesel Generator SIP -Safety Ielction Pump
CAROUNA POWER AND UGHT H. B. ROBINSON comeC AcOs
- HAW
- TRAINING
- SAFETYA
H. B. ROBINSON UNIT 2 ELECTRICAL DISTRIBUTION SYSTEM OVERVIEW HISTORY TRANSITION TO INHOUSE CAPABILITY SIGNIFICANT MODIFICATIONS FUTURE CONTROL RooM HABITABILITY AC SYSTEM EVALUATION CAPACITY HARDWARE DB-50 FUSE UPGRADE (W)
OTHER ALTERNATIVES
DB-50 BREAKER WHY 1991 ISSUES O
DESIGN BASIS o
W APPLICATION ISSUES o
EVALUATION OF OTHER ALTERNATIVES O
AC SYSTEM EVALUATION INFLUENCES SCHEDULE BASIS JCO BASIS ALL NON-LOCA/NoN-EDG PARALLEL ALL LOCA/NON-EDG PARALLEL o
<54KA; W LETTER 60KA o
CABLE REDUCES SC AMPS o
30 BOLTED FAULT EDG TEST CASES o
PROBABILITY Low O
CABLE REDUCES SC AMPs o
30 BOLTED FAULT o
DS SYSTEM LEVEL BACKUP EDG LOCA Loop o
EXTREMELY Low PROBABILITY EXPOSURE TIME, <1-2 MIN.
ROBINSON NUCLEAR PROJECT UNIT NO. 2 PLANT MODIFICATION M-947 ATTACHMENT 2 "SAFETY EVALUATION" List of Effective Pages PACE 1 2 3 4 5 6 7 8 9 10'11 12 13 14 REV X 0 0 0 0 0 0 0 0 0 0 0 0 0 M-947 Rev. 0 Cognizant Engineer Date MIS: 88-0623a
M-947-2 Page 2, Rev. 0 SAFETY EVALUATION FOR M-947 "SI PUMP AVAILABILITY UPGRADE" The purpose of this safety evaluation is to evaluate the subject plant modification in accordance with RNP POM, Section MOD-005 to meet the requirements of 10CFR50.59.
This will provide assurance that the proposed changes will not cause the plant to be operated outside of the boundaries of analyses performed to ensure that plant systems, structures, and components important to safety can perform their design functions during normal operation and analyzed accident conditions.
This safety evaluation does not take the place of design verifications and/or technical reviews of the subject plant modification.
I.
DESCRIPTION A.
Problem Definition In the process of reviewing plant documents for formulating a response to NRC letter NRC-88-017, it was discovered that at least one postulated single failure event existed which could result in the loss of the ability to automatically start two SI Pumps.
The plant was brought to cold shutdown and a team was mobilized to further investigate this concern. The team identified a total of five potential single failure scenarios that could cause the failure of two SI Pumps to automatically start on an SI signal.
Following are the scenarios identified:
MIS:88-0 6 23a
M-947-2 Page 3, Rev. 0 Scenario 1 Refer to Figure II-1; Safeguards Schematic CP-380, 5379-3238 (Rev. 11); and CWD Sheet 954 (Rev. 0).
With the present Emergency Switchgear breaker aLignment, E-1 tie breaker 228 normally closed, E-2 tie breaker 29B normally open and SI Pump B breaker 29C normally open, a failure of Train B dc power during an SI could result in only one SI Pump being available.
Under these conditions, the E-1/E-2 tie bus would be energized from E-1 (via bkr. 22B); however, no control power would be available to shut the breakers to SI Pump B and SI Pump C. On the other hand, if Train A DC power failed during an SI coincident with loss of offsite power, SI Pump A would not be available for two reasons as follows:
a)
The SI Pump A breaker cannot be closed since control power is unavailable, and b)
EDG A will be inoperable since the "Kl" relay (See CWD sh 954) will short the exciter field upon loss of control power.
Also, since Train A control power has failed, the tie breaker transfer will be defeated (no control power to trip '22B), thus SI Pump B would also be unavailable.
If either dc power system failed, it is possible to have two SI Pumps unavailable.
NOTE This problem has been corrected via Engineering Evaluation 88-013.
See I.B. "Proposed Changes for Scenario 1."
Therefore, the remaining scenarios are based upon the new alignment which is both tie breakers normally open and the SI Pump B Breaker normally closed.
MIS:88-0623a
M-947-2 Page 4, Rev. 0 Scenario 2 Reference safeguards schematic CP-380, 5379-3238 (Rev. 11).
Relay EIVP could fail (e.g., open coil), thus breaker 22B (E-1 tie bkr) would not close during SI sequencing. Since relay E1VP-1 would be energized, this would block relay 2SIB2 from closing backup breaker 29B (E-2 tie bkr.).
Additionally, the failure of relay EIVP will prevent the automatic sequencing of SI Pump A, thus making two SI Pumps unavailable. There is no "equivalent relay" to EIVP-l on Train B; thus, this problem only exists on Train A.
Scenario 3 Reference safeguards schematic CP-380, 5379-3238 (Rev. 11) and CWD sheets 891 (Rev. 11) and 896 (Rev. 11).
In the Train A Safeguards Logic, loss of voltage on line AIP (due to wire breaking, etc.)
would cause relay 52/22BX, which provides the "close" signal to E-1 tie breaker 228, to be inoperable. Since relay 2SIB1 (which is fed from line AP and, therefore, is still energized) "thinks" that tie breaker 228 closed, it will disable the Train B logic (relay 2SIB2) from transferring to the E2 tie breaker (298).
In addition, SI Pump A will not be "sequenced on" since its controlling relay (2SIA) is also powered from line AIP, which is deenergized.
Thus a single failure (loss of line AIP) could cause the loss of two SI Pumps (A & B).
Although less likely to occur (due to the El preferred bus logic), this problem also exists in the Train B logic. This scenario is only applicable to the first five seconds of SI sequencing since there are annunciation and indication for loss of AIP or BIP voltage. If this power failure occurred during normal plant operating modes, it would be corrected in accordance with Plant Operating Procedures. Therefore, the power loss should not be a pre-existing condition to the SI.
MIS:88-0623a
M-947-2 Page 5, Rev. 3 Scenario 4 Refer to drawings CP-380, 5379-3238 (Rev. 11) and CWD sheet nos.
954 (Rev. 0), 891 (Rev. 11) and 896 (Rev. 11).
Upon initiation of a safety injection coincident with loss of offsite power, the Emergency Buses will strip and the EDG wiLl start and connect to the buses. The buses will then sequentially load.
This will result in tie breaker 22B being closed such that SI Pump B is fed from E-1 (the "preferred" bus).
If, after a successful sequencing operation, Train A dc power fails, EDG A will be made inoperable due to relay K1 shorting the exciter field.
Also, all breaker operations will fail since there will not be any control power available. Therefore, there will be no power available to. bus E-1 (SI Pump A unavailable) and the tie breaker transfer will be disabled (SI Pump B unavailable) since breaker 228 cannot trip. Again, this will result in the unavailability of two SI Pumps due to a single failure. Although less likely to occur (due to the El preferred bus logic), this problem also exists on Train B.
Scenario 5 If, during the first five seconds of safety injection sequencing, the dc control power to the E-1 switchgear is lost (i.e., not a total loss of Train A control power), the ability to close the SI Pump A breaker and E-1 tie breaker 22B (for SI Pump B) is lost.
However, the Train A safeguards logic "thinks" that the E-1 breakers closed since the sequencer logic dc control power is still available. Therefore automatic transfer of the tie breakers will not occur. This scenario is less likely but possible on bus E-2 also.
Again, two SI Pumps will be unavailable due to a single failure. If the dc control power to E-1 fails after five seconds into the sequence, SI Pump A would have started and will continue to run along with SI Pump C.
B.
Description of Proposed Changes The proposed changes listed below are numbered in the same order as:
the "scenarios" discussed above' MIS:88-0623a
M-947-2 Page 6, Rev. 0 Proposed Changes for Scenario I The following changes have already been implemented via Engineering Evaluation 88-013.
They are discussed in this modification package and Safety Evaluation only for the purpose of completeness and traceability.
Procedurally, leave both tie breakers open (22B and 29B) and leave SI Pump B breaker (29C) closed (See Figure II-1).
Then even if Train B control power is lost, only SI Pump C would be unavailable (i.e., 22B would close powering SI Pump B from E-1).
If Train A control power is lost during an SI coincident with loss of offsite power, only SI Pump A would be unavailable (i.e., 29B would close powering SI Pump B from E-2).
Proposed Changes for Scenario 2 Eliminate relay ElVP-l thus preventing conflicting information due to failure of one of the two parallel relays (i.e., E1VP and E1VP-1).
This will be accomplished by changing out the existing ElVP relay to a Westinghouse type NBFD 84S which has eight normally open and four normally closed contacts. A normally closed contact of new E1VP would then be used in place of the existing E1VP-1 normally closed contact in the Train B 2SIB2 relay coil circuit.
Field verification has confirmed that only one contact of relay ElVP-1 is being used. See Figure 11-2.
Proposed Changes for Scenario 3 The wire supplying power to the 52/22BX and 52/29BX circuits (wire number AIP or BIP as applicable) will be relocated to take power directly off the main fuse of the safeguards cabinet such that a break in wire AIP will not affect the circuit. Field verification has shown that these circuits are presently fed directly from the fuse and thus further modifications are not required.
MIS:88-0623a
M-947-2 Page 7, Rev. 0 Proposed Changes for Scenario 4 See Figure.II-3.
Two type NBFD 22S relays (DCI/E-1 and DC2/E-1 for Bus E-1 and DC1/E-2 and DC2/E-2 for Bus E-2) will be installed in each Emergency Bus to provide redundant monitoring of DC control power.
A second shunt trip coil will be installed on each tie breaker (22B and 29B) which will receive a trip signal from a simultaneous contact closure from both of the new dc power monitoring relays upon loss of normal dc control power to the breaker.
The control power to this new trip coil will be from the opposite train via dedicated fuses.
Proposed Changes for Scenario 5 See Figures 11-2 and 11-3. In the Train A Safeguards logic, add parallel normally open contacts of new relays DC1/E-1 and DC2/E-1 in series with the present parallel contacts of 271X5/E-1 and 272X5/E-1.. This will disable the safeguards sequencing logic upon loss of E-1 control power since the breakers cannot be closed anyway without control power. It will also drop out safeguards relays E1VP and 2SIB1 thus removing the "blocking signal" in the Train B safeguards logic.
Similar changes will be made in the Train B Safeguards logic.
II.
SAFETY ANALYSIS A.
FSAR Review In order to determine if changes in the facility or procedures as described in the Safety Analyses Report (SAR) or testing not described in the SAR would be made by implementation of the subject modification, the Updated FSAR chapters/sections listed in the "Reference" section (V.A.4) of this safety evaluation were reviewed in detail.
The Table of Contents of the Updated FSAR was reviewed for applicability.
MIS:88-0623a
M-947-2 Page 8, Rev. 0 This review has shown that the proposed changes would be a change in the facility as described in the FSAR. In particular, Chapter 8.0 of the FSAR is devoted to a discussion of the Electrical Distribution System. This chapter provides details of the tie breaker transfer scheme of the emergency switchgear and discusses the availability of SI Pump 8 during an SI event because of the automatic transfer capabilities.
Additionally, Section 6.3 discusses the Safety Injection System, and Section 7.3 discusses instrumentation associated with the Engineered Safety Feature Systems (including the Safety Injection System).
This review has shown that the proposed changes would require a change in procedures as described in the FSAR. In particular, The RNP Plant Operating Manual (POM) would require changes (such as, OP-603 and Surveillance Test Procedures).
The proposed changes do not constitute a test or experiment not described in the FSAR.
Since implementation of the subject modification would involve a change to the facility and procedures as described in the FSAR, the proposed changes may be implemented without prior approval of the NRC only if there are no changes to the Technical Specifications and an unreviewed safety question (USQ) does not exist.
MIS:88-0623a
M-947-2 Page 9. Rev. 0 B.
Technical Specifications Review In order to determine if the proposed plant modification includes a change in the RNP Operating License Technical Specifications, the Technical Specifications sections listed in the "References" section (V.A.5) of this safety evaluation were reviewed in detail.
The Table of Contents of the Technical Specification was reviewed for applicability.
The review indicates that changes to the RNP Technical Specifications will not be required as a result of implementing the subject modification.
C.
Basis for Unreviewed Safety Question Determination The following discussion will serve as the basis for determining if an unreviewed safety question.(USQ) exists (i.e., it will provide the basis for answering "yes" or "no" to the safety evaluation questions in Section III).
- 1.
The proposed changes were reviewed to determine if they alter the design, function, or method of performing the function of any component, system, or structure which could initiate or which is required to.mitigate any accident.previously evaluated in the FSAR. The review has concluded that systems associated with accident mitigation would be altered since the design of the Safeguards logic and tie breaker tripping logic would be changed. The basic functioning and method of performing the function of the Safeguards logic has not changed.
The logic still, upon initiation, sequentially loads the same equipment onto the same Emergency Buses with the same timing sequence as before. The design change is in the initiation circuit.
Previously, sequencing was started upon receipt of an SI signal as long as voltage was present on the s itchgear.- The changes proposed byl this modification no require dc control power to be present also.
MIS:88-0623a
M-947-2 Page 10, Rev. 0 This is a "logical" change to the Safeguards Logic since if dc control power was not available at the switchgear, the sequencing would be useless because there would be no control power to close the breakers. The consequences of certain accidents previously analyzed in the FSAR have been reduced since the proposed changes correct several "single-failure" scenarios which could leave the plant with only one SI Pump after Safeguards sequencing. The probability of occurrence of an accident previously evaluated in the FSAR is not increased since no changes were made to equipment which could initiate an analyzed accident (i.e., Safeguards logic is only required for accident mitigation as is SIP B).
Note -
the tie breakers are only required for the selection of power to SIP B. The probability of occurrence or the consequences of a malfunction of equipment important to safety has been decreased by this modification since several single-failure scenarios have been corrected. For instance, after the proposed changes, the failure of either Battery A or Battery B will not prevent the automatic sequencing of two SI pumps, whereas without the proposed changes, it could have. This same reasoning also applies to the changes associated with the other scenarios, such as failure of relay E1UP. No changes have been made to the safety functions of any equipment important to safety. Design margins have not been changed, since the timing of the Safeguards logic has not been altered. In fact, if anything, the design margin has been increased (over that which is existing, not over that which has been analyzed), since the modification increases the availability of the second SI Pump.
MIS: 88-0623a
M-947-2 Page 11, Rev. 0
- 2.
The equipment added to the Safeguards logic has been selected based on its reliability and RNP's operating
- experience with similar equipment already in use in safety-related applications throughout the plant (including Safeguards). The design of the added equipment (in the Safeguards logic) is redundant so that the failure of one dc monitoring relay will not prevent the actuation of the sequencing operation upon receipt of an Si signal.
The redundancy of the dc monitoring circuit and its associated interlocks is similar to the existing Emergency Bus undervoltage monitoring scheme.
.The normal failure mode of a breaker trip coil is an "open circuit."
If this were to occur, the "loss of dc control power" tripping capability of the tie breaker would be disabled. Since the trip coil is normally not energized, this failure is very unlikely, but would be picked up during Surveillance Testing. This "open circuit" failure would not affect the normal operation of the tie breakers (i.e., they would still operate as they have in the past).
In the extremely unlikely event of a short circuit or overload in this new trip coil circuit, the current would be interrupted by redundant fuses located at the source of power (opposite train switchgear). Redundancy in fuses is incorporated by virtue of having fuses in both legs of the dc power supplies to the new trip coils (the dc distribution system is ungrounded). Separation of the opposite train dc power within the switchgear has been considered. The wiring is run in nonconductive "liquid-tight" type flexible conduit to protect the circuit as much as possible from potential hazards and failures within the switchgear. Again,ithe trip coil circuits are fused to MIS:88-0623a
M-947-2 Page 12, Rev. O isolate this opposite train circuit should a failure within the switchgear create a fault on this opposite train circuit. All raceway and equipment have been mounted taking seismic qualifications into consideration. The modifications to the tie breakers themselves have been evaluated by Westinghouse to ensure that equipment qualification is maintained. Based upon the above discussion, the proposed changes do not introduce any common-mode failure potentials or reduce the level of redundancy for equipment important to safety; nor do they change potential single-failures to common-mode failures or cause events previously considered incredible to become credible.
- 3.
There are no Technical Specification margins of safety affected by the proposed changes since no changes are being made in the timing sequence. The proposed changes are actually ensuring that the present margins of safety associated with Safety Injection are maintained by increasing the availability of a second SI Pump.
B.
Additional Considerations Westinghouse engineers have reviewed, onsite, all of the single-failure scenarios and proposed changes discussed in this Safety Evaluation. They have documented in a letter that they agree with the scenarios and concur with the proposed changes. Their review included both technical and nuclear safety considerations.
MIS:88-0623a
M-947-2 Page 13, Rev.
III.
SAFETY EVALUATION A.
Unreviewed Safety Question Determination In order to determine if the proposed changes involve an unreviewed safety question (USQ) the RNP interpretation of the three questions listed in 10CFR50.59 will be addressed. The RNP interpretation of the 10CFR50.59 questions is outlined in RNP POM Section MOD-005 and consists of answering the following questions:
- 1.
Is the probability of occurrence or the consequences of an accident or malfunction of equipment important to safety previously evaluated in the safety analysis report increased?
No, based on "Safety Analysis,"Section II.C.1.
- 2.
Is a possibility for an accident or malfunction of a different type than any evaluated previously in the safety analysis report created?
No, based on "Safety Analysis,"Section II.C.2.
- 3.
Is the margin of safety as defined in the basis for any Technical Specification reduced?
No, based on "Safety Analysis,"Section II.C.3.
IV.
SUMMARY
The proposed changes are a change in the facility and procedures as described in the FSAR. However, the proposed changes do not include changes in the Technical Specification..0d-h-a an unreviewed safety question Therefore, in accordance with IOCFR50.59, the proposed chan es may be implemented without prio approval from the NRC.
MIS:88-0623a
M-947-2 Page 14, Rev. C V.
MISCELLANEOUS A.
References L.
POM Sections
- a.
MOD-005, Revision 10, "Modification/Package Development and Revision"
- b.
OP-603, Revision 20, "Electrical Distribution"
- c.
EPP-1, Revision 3, "Loss of All AC Power"
- d.
EPP-3, Revision 3, "Loss of All AC Power with SI Required"
- e.
SD-16, Revision 27, "Electrical System"
- 2.
Letter NRC-88-017
- 3.
10CFR50.59, "Changes, Tests, and Experiments"
- 4.
FSAR Chapters/Sections
- a.
Chapter 1, Section 1.8, "Conformance to NRC Regulatory Guides"
- b.
Chapter 6, Section 6.3, "Emergency Core Cooling System"
- c.
Chapter 7, Section 7.3, "Engineered Safety Features Systems"
- d.
Chapter 8, "Electric Power"
- e.
Chapter 15, "Accident Analysis"
- 5.
Technical Specification Sections (including bases)
- a.
3.3, "Emergency Core Cooling Systems, etc.
- b.
3.5, "Instrumentation Systems"
- c.
3.7, "Auxiliary Electric Systems"
- d.
4.5, "Emergency Core Cooling, etc., Systems Tests"
- e.
4.6, "Emergency Power System Periodic Test" 6.,
Engineering Evaluation 88-013 7..
Drawing B-190628 Sheets
- a.
954 (Rev. 0)
- b.
891 (Rev. 11)
- c.
896 (Rev. 11)
- 8.
Drawing CP-380, 5379-1238 (Rev. 11)
MIS:88-0623a
Page 11. R.
FIGURE II-1 BREAKER ALIGNMENT CHANCES *
/ V..L A<
MIS:88-0623a
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MIS:88-0623a
Pate.3.
Re;.0 FIGURE 11-3 El AND E2 SWITCHCEAR CHANGES
-A1 77-/
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