B12648, Proposed Tech Specs,Changing Limiting Condition for Operation 3.4.6.2(c) on Page 3/4 4-9 from 0.5 Gpm to 0.15 Gpm for Any One Steam Generator
| ML20238E995 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 09/30/1987 |
| From: | NORTHEAST NUCLEAR ENERGY CO. |
| To: | |
| Shared Package | |
| ML20238E981 | List: |
| References | |
| B12648, TAC-65852, TAC-66116, NUDOCS 8709150329 | |
| Download: ML20238E995 (6) | |
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4 Docket No. 50-336 B12648 Attachment 1 Millstone Nuclear Power Station, Unit No. 2 Proposed Changes to Technical Specifications 1
1 September 1987 0709150329 070904 PDR ADOCK 05000336 p PDR
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I i REACTOR COOLANT SYSTEM REACTOR COOLANT SYSTEM LEAKAGE LIMITING CONDITION FOR OPER ATION 3.4.6.2 Reactor Coolant System leakage shall be limited to:
- a. No PRESSURE BOUNDARY LEAKAGE,
- b. 1 GPM UNIDENTIFIED LEAKAGE,
- c. I GPM total primary-to-secondary leakage through both steam generators and 0.15 GPM through any one steam generator, and
- d. 10 GPM IDENTIFIED LEAKAGE from the Reactor Coolant System.
APPLICABILITY: MODES 1, 2,3 and 4.
ACTION:
- a. With any PRESSURE BOUNDARY LEAKAGE, be in COLD SHUTDOWN within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.
- b. With any Reactor Coolant System leakage greater than any one of the above limits, excluding PRESSURE BOUNDARY LEAKAGE, reduce the leakage rate to within limits within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or be in COLD SHUTDOWN within the next 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.
SURVEILLANCE REQUIREMENTS l l
4.4.6.2 Reactor Coolant System leakages shall be demonstrated to be within each of the above limits by:
- a. Monitoring the containment atmosphere particulate radioactivity at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
- b. Monitoring the containment sump inventory at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, ,
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- c. Performance of a Reactor Coolant System water inventory balance j at least once per 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> during steady state operation except when i operating in the shutdown cooling mode. l I
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i REACTOR COOLANT SYSTEM BASES i
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evidence of mechanical damage or progressive degradation due to design, manufacturing errors, or inservice conditions that lead to corrosion. Inservice inspection of steam generator tubing also provides a means of characterizing the nature and cause of any tube degradation so that corrective measures can be taken.
The plant is expected to be operated in a manner such that the secondary l coolant will be maintained within those chemistry limits found to result in negligible corrosion of the steam generator tubes. If the secondary coolant chemistry is not maintained within these limits, localized corrosion may likely result in stress corrosion cracking.
The extent of cracking during plant operation would be limited by the limitation of steam generator tube leakage between the primary coolant system and the. secondary coolant system (primary-to-secondary leakage = 0.15 GPM, l per steam generator). Cracks having a primary-to-secondary leakage less than this limit during operation will have an adequate margin of safety to withstand the loads imposed during normal operation and by postulated accidents.
Operating plants have demonstrated that primary-to-secondary leakage of 0.15 gallon per minute can readily be detected by radiation monitors of steam l generator blowdown. Leakage in excess of this limit will require plant shutdown and an unscheduled inspection, during which the leaking tubes will be located and plugged.
Wastage-type defects are unlikely with proper chemistry treatment of the secondary coolant. However, even if a defect should develop in service, it will be found during scheduled inservice steam generator tube examinations.
Plugging or sleeving will be required for all tubes with imperfections exceeding the plugging limit of 40% of the tube nominal wall thickness. Sleeving repair will be limited to those steam generator tubes with a defect between the tube sheet and the first eggcrate support. Tubes containing sleeves with imperfections exceeding the plugging limit will be plugged. Steam generator tube inspections of operating plants have demonstrated the capability to reliably detect degradation that has penetrated 20% of the original tube wall thickness.
Whenever the results of any steam generator tubing inservice inspection fall into Category C-3, these results will be promptly reported to the Commission pursuant to Specification 6.9.1 prior to resumption of plant operation. Such cases will be considered by the Commission on a case-by-case basis and may result in a requirement for analysis, laboratory examinations, tests, additional eddy-current inspection, and revision of the Technical Specifications,if necessary.
I MILLSTONE - UNIT 2 B 3/4 4-2a
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REACTOR COOLANT SYSTEM BASES-l 3/4.4.6 REACTOR COOLANT SYSTEM LEAKAGE 3/4.4.6.1 LEAKAGE DETECTION SYSTEMS The RCS leakage detection systems required by this specification are provided to monitor and detect leakage from the Reactor Coolant Pressure Boundary. These detection systems are consistent with the recommendations of Regulatory Guide 1.45, " Reactor Coolant Pressure Boundary Leakage Detection Systems."
3/4.4.6.2 REACTOR COOLANT SYSTEM LEAKAGE Industry experience has shown that while a limited amount of leakage is expected from ~the RCS, the unidentified portion of this leakage can be reduced to a threshold value of less than 1 GPM. This threshold value is sufficiently low to ensure early detection of additional leakage.
The 10 GPM IDENTIFIED LEAKAGE limitation provides allowance for a limited amount of leakage from known sources whose presence will not interfere with the detection of UNIDENTIFIED LEAKAGE by the leakage detection systems.
The . total steam generator tube leakage limit of 1 GPM for all steam generators ensures that the desage contribution from the tube leakage will be limited to a small fraction of Part 100 limits in the event of either a steam generator tube rupture or steam line break. The 1 GPM limit is consistent with the assumptions used in the analysis of these accidents. l PRESSURE BOUNDARY LEAKAGE of any magnitude is unacceptable since it may be indicative of an impending gross failure of the pressure boundary. !
Therefore, the presence of any PRESSURE BOUNDARY LEAKAGE requires the unit to be promptly placed in COLD SHUTDOWN.
The 0.15 GPM Primary to Secondary leakage limitation assures structural integrity. A tube with a through-wall circumferential crack which leaks at 0.15 GPM under normal operating conditions retains the structural margins recommended in Regulatory Guide 1.121. In addition, the total leakage under accident conditions would remain below the 1 GPM limit.
l MILLSTONE - UNIT 2 B 3/4 4-3 i
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Docket No.' 50-336 '
B12648 Attachment 2 Millstone Nuclear Power Station, Unit No. 2 Evaluation Results i
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TABLE 1 n MILLSTONE UNIT NO,2 ), 'd PRIMARY-TO-SECONDARY LEAKAGE LIMIT '
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e, y* i Inspection Result: Indication Over a 2000 Arc and Maximum ;.o;j c 1 Metal Loss Over a 400 Arc
- 4 Equivalent Analyzed Defect: 15% Through Wall Over a 3600 Arc and 100% Through Wall Over a 1300 Arc Analysis Result: Estimated Burst Pressure of 4455 psi Actual Loads: Normal Operating Pressure of 1365 psi; Maximum Accident Equivalent Pressure (steady plus allowance for dynamic effects) of 3150 psi Safety Factors: Safety Factor Against Normal Operating Conditions of 3.3; Safety Factor Against Accident Conditions of 1.4 Regulatory Guide 1.121 Safety Factor Against Norrnal Operating Recommended Safety Factors: Conditions of 3.0; Accident Conditions of 1.4 l'
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