ML19210E534
| ML19210E534 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 10/29/1979 |
| From: | Schwencer A Office of Nuclear Reactor Regulation |
| To: | Burstein S WISCONSIN ELECTRIC POWER CO. |
| References | |
| TAC-12663, TAC-12664, NUDOCS 7912050193 | |
| Download: ML19210E534 (7) | |
Text
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[ t ) v' g NUCLEAR REGULATORY COMMifdlON 3 E WASHINGTON, D. C. 20555 Ci-{o OCTOBER 2 9 1979 Docket Nos. 50'-266 and 50-301 Mr. Sol Burstein Executive Vice President Wisconsin Electric Power Company 231 West Michigan Street Milwaukee, Wisconsin 53201
Dear Mr. Burstein:
The staff has recently completed a review of the LER',s and Technical Specification requirements related to the Control Rod Position Indication Systems (RPI) at Westinghouse PWRs. We have detemined that a wide vcria-tion exists in the number of LERS received and the technical specification requirements and have, therefore, decided to clarify our requirement::. At the time of development of the Standard Technical Specifications, a systematic attempt was made to clarify potentially ambiguous specifications. One such specification was the control rod misalignment specification for Westinghouse-designed reactors. Westinghou'se has perfomed safety analyses for control rod misalignment up to 15 inches or 24 steps (one step equals 5/8 inch). Since analysis of misalignments in excess of this arrount have not been submitted, we have imposed an LCO restricting continued operation with a misalignment in excess of 15 inches. Because the analog control rod position indication system has an uncertainty of 7.5 inches (12 steps), when an indicated deviation of 12 steps exists, the actual misalignment may be 15 inches. This is because one of the coils, spaced at 3.75 inches, may be failed without the operator knowing about it. The Standard Technical Specifications were written to eliminate any confusion about this, and allow a deviati.on of up to 12 indicated steps. Surveillance requirements, on the indication accuracy of 12 steps were also prepared to ensure that the 15 inch LCO is met. There is no difference intended in requirements issued for any Westinghouse reactor. Westinghouw has infomed the NRC that all of their customers have been informed of this and that all the licensees should be following the same procedures regardless of the language of their Technical Specification. That is, plants with Technical Specifications written in tems of 15 inch misalign-ment should be considering the 12 step instrument inaccuracy when menitering rod position. A related problem is that the installed analog control rod position indicating syster$ equipment may not, in some areas, be adequate to maintain the control rod misalignment specification requirement because of drift problems in the calibration curves. This is evidenced by numerous LER's concerning rod position indication accuracy. In these cases, the uncertainty may be more than 12 steps. 1498 292 83[3 5
Mr. Sol Burstein OCTOBER 2 9 1979 Wisco~nsin Electric Power Company The present Westinghouse Standard Technical Specifications (Tindicated p W-STS) require all full length control reds to be positioned within i 12 steps of their group step counter demand position. Since numerous problems have developed in signal conditioning circuits for display indication of control rod position, the staff has determined that the '.! indicated position" requirement may be fulfilled by voltage measurements obtained from the position indication mechanism (and therefore no LER need be submitted) provided a sufficient data base has oeen established to ensure a correlation between voltage and position. A copy of the current, applicable W-STS Specifications (3/4.1.3.1 and 3/4.1.3.2) tre attached for your information and consideration. It is requested that you review your present technical specifications to ensure that the control rods are required to be maintained within i 12 steps indicated and that the rod position indication system is verified to be accurate to within 12 steps. If your review indicates that this is not the case, you should so inform the Commission within 30 days of your receipt of this letter together with your plans to correct the deficiencies. Any needed corrective actions may take several foms; such as (1) revising your technical specifications to limit control rod misalignment to no more than + 12 steps indicated position, (2) seeking relief by perfoming analyses justifying (with penalties if needed) greater misalignments, or (3) proposing alternate or supplemental monitoring specifications to demonstrate compliance with the i 12 step indicated alignment equirement. If you have any questions on this matter, please contact us. Sincerely, /Jdue6 A. Schwencer, Chief Operating Reactors Branch #1 Division of Operating Reactors
Enclosure:
W-STS Specifications _ 3/4.1.3.1 ana 3/4.1.3.2 cc: w/ enclosure See next page e 1498 293
= "r. ' Sol Eurstein CCTOBEn 2 e R19 Wisconsin Electric Power Company cc: Mr. Bruce Churchill, Esquire Shaw, Pittman, Potts and Trowbridge 1800.M Street, N.W. Washington, D. C. 20036 Document Department University of Wisconsin Stevens Point Library Stevens Point, Wisconsin 54481 Mr. Glenn A. Reed, Manager Nuclear. Operations Wisconsin Electric Power Company Point Beach Nuclear Plant 6610 Nuclear Road Two Rivers, Wisconsin 54241 i -p p 6 4 o Q 0 9 O 1498 294
REACTIVITY CONTROL SYSTEMS 3/4.1.3 MOVABLE C0NTROL ASSEMBLIES GROUP HEIGHT LIMITING CONDITION FOR OPERATION 3.'1. 3.1 All full length (shutdown and control) rods, and all part length rods which are inserted in' the core, shall be OPERABLE and positioned within ! 12 stcps (indicated position) LT.their group step counter demand position. APPLICABILITY: MODES 1* and 2* ACTION: With one or more full length rods inoperable due to being immovable a. as a result of excessive friction nr mechanical interference or known to be untrippable, determine that the SHUTDOWN MARGIN require-ment of Specification 3.1.1.1 is satisfied within 1 hour and be in HOT STANDBY within 6 hours. b. With more than one full or part length rod inoperable or misaligned fro,the group step counter demand position by more than 12 steps (indicated position), be in HOT STANDBY within 6 hours. I c. With one full or part length rod inoperable due to causes other than addressed by ACTION a, above, or misaligned from its group step counter demand height by more than 1 12 steps (indicated position), POWER OPERATION may continue provided that within one hour either: 1. The rod is restored 'to OPERABLE status within the above alignment requirements, or 2. The rad is declared inoperable and the SHUTDOWN MARGIN requirement of Specification 3.1.1.1 is satisfied. POWER OPERATIGT. may then continue provided that: a) A reevaluation of.each accident analysis of Table 3.1-1 is performed within 5 days; this reevaluation shall confirm that the previously analyzed results of these accidents remain valid for the duration of operation under these conditions. b) The SHUTDOWN MARGIN requirement of Specification 3.1.1.1 is determined at least once per 12 hours. "See Special Test Exceptions 3.10.2 and 3.10.3. l498 295 ~ W-STS 3/4 1-14 007 1 E76
REACTIVITY CONTROL SYSTEMS LIMITING CONDITION FOR' OPERATION (Continued) c) A power distribution map is obtajned from the movable incore detectors and F (Z) and F are verified to be within their limits wikhin 72 hobHrs. d) [ither the THERMAL POWER level is reduced to less than or equal to 75% of RATED THERMAL POWER within one hour and within tne next 4 hours the high neutron flux trip setpoint is reduced to less than or equal to 85% of RATED THERMAL POWER, or ~) The remainder of the rods in the group with the inoperable e re-are aligned to wit; 'n 112 steps of the inoperable rod within one hour while maintaining the rod sequence and insertion limits of Figures (3.1-1) and (3.1-2); the THERMAL POWER level shall be restricted pursuant to Speci-fication (3.1.3.6) during subsequent operation. SURVEILLANCE RE0VIREMENTS 4.1.3.1.1 The position of each full and part length rod shall be determined to be within the group demand limit by verifying the individual rod positions at least once per 12 hours except during time intervals when the Rod Position Deviation Monitor is inoperable, then verify the group positions at least once per 4 hours. 4.1.3.1.2 Each full length rod not fully inserted and each part length rod which is inserted in the core shall be determined to be OPERABLE by movement of at least 10 steps in any one direction at least once per 31 days. 1498 296 W-STS 3/4 1-15 MAR 1 5 13' 7 7
TABLE 3.1-1 ACCIDENT ANALYSES REQUIRING REEVALUATION IN THE EVENT OF AN INOPERABLE FULL OR PART LENGTH ROD Rod Cluster Control Assembly insertion Characteristics Rod Cluster Control Assembly Misalignment Loss Of Reactor Coolant From Small Ruptured '>ipes Or From Cracks In large Pipes Which Actuates The Emergency Core Cooling System ~ Single Rod Cluster Control Assembly Withdrawal At Full Power Major Reactor Coolant System Pipe Ruptures (Loss Of Coolant Accident) Major Secondary System Pipe Rupture Rupture of a Control Roc Drive Mechanism Housing (Rod Cluster Control Assembly Ejection) 1498 297 W-STS 3/4 1-16 0CT 1 1976
REACTIVITY CONTROL SYSTEMS POSITION INDICATION SYSTEMS-OPERATING LIMITING CONDITION FOR OPERATION 3.1.3.2 The shutdown, control and part length control rod position indication system and the demand position indication system shall be OPERABLE and capable of determining the control rod positions within 12 steps. APPLICABILITY: MODES 1 and 2. ACTION: a. With 'a maximum of one rod position indicator per bank inoperable either. 1. Datermine the position of the non-indicating rod (s) indirectly by the inovable incore detectors at least once per 8 hours and immediately after any motion of the non-indicating rod which exceeds 24 steps in one direction since the last determination of the rod's position, or 2. ' Reduce THERMAL POWER TO less than 50% of RATED THERMAL POWER within 8 hours. b. With a maximum of one demand position indicator per bank inoperable either: 1. Verify that all rod position indicators for the affected bank are OPERABLE and that the most withdrawn red and the least withdrawn rod of the bank are within a maximum of 12 steps of each other at least once per 8 hours, or 2. Reduce THERMAL POWER to less than 50% of RATED THERMAL POWER within 8 hours. SURVEILLANCE REQUIREMENTS 4.1.3.2 Each rod position indicator shall be determined to be OPERABLE by . verifying that the demand position indication system and the rod position indication system agree within 12 steps at least once per 12 hours except during time intervals when the Rod Position Deviation Monitor is inoperable, then compare the demand position indication system and the rod position indica' tion system at least once per 4 hours. JUL 151979 -W-STS 3/4 1-17 1498 298 _ _.}}