ML20246C185
| ML20246C185 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 05/02/1989 |
| From: | Wang A Office of Nuclear Reactor Regulation |
| To: | Mroczka E NORTHEAST NUCLEAR ENERGY CO. |
| References | |
| GL-88-17, TAC-69746, NUDOCS 8905090282 | |
| Download: ML20246C185 (5) | |
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,p May 2, 1989 Docket-No. 50-213 Mr. E. J. Mroczka Senior Vice President Northeast Nuclear Energy Company Connecticut Yankee Atomic Power Company P. O. Box 270 Hartford, Connecticut 06141-0270
Dear Mr. Mroczka:
SUBJECT:
COMMENTS ON THE NORTHEAST NUCLEAR ENERGY COMPANY RESPONSE TO GENERIC LETTER 88-17 WITH RESPECT TO EXPEDITIOUS ACTIONS FOR LOSS OF DECAY HEAT REMOVAL FOR HADDAM NECK (TAC NO. 69746)
Generic Letter (GL) 88-17 was issued on October 17, 1988 to address the potential loss of decay heat removal (DHR) during nonpower operation.
In the GL, we requested (1) a description of your efforts to implement the eight recommended expeditious actions of the GL, and (2) e description of the enhancements, specific plans and a schedule for implementation of the six recommended program enhancements. By letter dated December 23, 1988, CYAPC0 described the expeditious actions taken which are an interim measure to achieve an immediate reduction in risk associated with reduced inventory operation. These actions will be supplemented and in some cases replaced by programmed enhancements.
The NRC staff has reviewed your December 23, 1988 response to GL 88-17 on expeditious actions and concludes that your response meets the intent of the GL.
However, while your. responses in general were complete, for some items your responses were brief and lacked some of the details provided in of GL 88-17. Because some of your responses were brief, the NRC staff has provided several observations regarding the expeditious actions CYAPCO has taken. These observations are provided so that CYAPC0 can assure itself the expeditious actions as described in the response to the GL are
. consistent with the NRC staff's interpretation cf those actions. While no response is required to the following observations, we do intend to audit both your responses to the expeditious actions and your programmed enhancecnt program:
1.
You have provided an extensive list of training related to reduced RCS inventory operation, where lowered loop operations are anticipated, with licensed and unlicensed personnel of your staff.
In the GL this item was intended to include all personnel who can affect reduced inventory operation, including maintenance personnel. Although you state that maintenance personnel do not receive NSSS classroom system training, you have indicated that avoidance of maintenance-related NSSS perturbation is achieved by supervisory control of maintenance activities. You have further stated that during plant outages, daily meetings are conducted among the various maintenance and operations activities. At these tvb 8905090282 890502 PDR ADOCK 05000213 V'
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meetings the supervisor should inform the maintenance personnel of their possible harmful interaction with mid-loop operation. Precautions for avoidance should be explained, including a background of past problems experienced at other plants and for Haddam Neck, if any.
2.
You state that a "new general operating procedure on mid-loop operations will provide instructions and administrative controls to assure that for reduced inventory operations, containment isolation will be able to be set within a certain time frame that will assure containment closure will be achieved prior to the time at which a core uncovery could result from
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a loss of residual heat removal (RHR) coupled with an inability to l
initiate alternate cooling or addition of water to the reactor coolant system (RCS) inventory."
It is not stated if you have completed the
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necessary analysis yet.
In the meantime, you have not presented any times for closure. GL 88-17 states that " containment penetrations including the equipment hatch, may remain open provided closure is reasonably assured within 2.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> of initial loss of DHR." This time will be less if there are vent areas totaling greater than one sq)uare inch in the cold leg (see Enclosure 2, Section 2.2.2 of GL 88-17.
In some plants, the quick closure of the equipment hatch is achieved by the installation of a reduced number of bolts.
If you plan to use less than the full complement of bolts for sealing the equipment hatch, then you should first verify that you can make a proper seal of the periphery mating surfaces to meet the closure criteria.
3.
For level measurement you state that two temporary pressure transducers will be installed at the drain header to provide independent level indication and alarm in the control room. These are only to be used during a reduced inventory condition and therefore will be disconnected following the outage. You have not provided information on the range of the level reading and its relationship to the mid-loop range of concern.
Also, the accuracy of the readings has not been stated. When two instruments are in place, care should be taken to resolve any discrepancy between the two measurement systems. Also, the pressure of the reference leg should approximate the pressure in the void in the hot leg or be compensated to obtain a correct value.
4.
For the expeditious action regarding provision of at least two available or operable means of adding inventory to the RCS that are in addition to pumps that are a part of the normal DHR systems, you have provided i
information on three means. Two of these means involve pumps, a charging pump and a purification pump, both taking suction from the refueling water storage tank (RWST). The third means is gravity feed from the RWST.
For the charging pump you indicate that it can be lined up to discharge to the loop 2 cold leg or through one of the fill headers on an operable loop. As alluded to in Enclosure 2, Section 2.2.2 of GL 88-17, if openings totaling greater than one square inch exist in the cold legs, reactor coolant pumps and crossover piping of the RCS, the core can uncover quickly when pressurized under loss of RHR conditions.
If this
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situation should arise, it is generally more effective to inject makeup water into the hot leg rather than the cold leg. When using gravity drain from the RWST a proper means for venting must be in place and verified by calculations (see next item).
5.
You indicate that gravity feed from the refueling water storage tank (RWST) is a possible source for makeup to the RCS. You have not stated any specific opening to relieve pressure. The removal of a pressurizer manway or steam generator manway for example, is a means to provide RCS venting. Calculations need to be performed to verify the effectiveness of RCS openings, however, because even for relatively large hot side openings in the RCS, pressurization to several psi can still result. For example, with removal of a pressurizer manway large steam flows in combination with flow restrictions in the surge line and lower pressurizer hardware may still lead to pressurization.
This closes out the staff review of your responses to the expeditious actions listed in the GL. The area of programmed enhancements will be addressed in a separate letter.
If you have any questions please call me at (301) 492-1313.
Sincerely, n
OM Alan B. Wang, Projec ! anager M
Project Directorate I-4 Division of Reactor Projects I/II Office of Nuclear Reactor Regulatien cc: See next page
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- 4. g Mr. Edward Ji Mboczka Connecticut Yankee Atomic Power ' Company Haddam Neck Plant cc:
- Gerald Garfield, Esquire R. M. Kacich, Manager
- Day, Berry and Howard Generation Facilities Licensing Counselors at, Law.
Northeast Utilities Service Company City Place.
Post Office Box 270
- Hartford, Connecticut- ' 06103-3499 Hartford, Connecticut 06141-0270
- W. D. Romberg, Vice President D. 0. Nordquist Nuclear Operations Director of Quality Services Northeast Utilities Service Company Northeast Nuclear Energy Company
- Post Office Box 270 Post Office Box 270
. Hartford, Connecticut 06141-0270 Hartford, Connecticut 06141-0270 Kevin McCarthy, Director Regional Administrator i
Radiation Control Unit _
Region I i
Department of. Environmental Protection U. S. Nuclear Regulatory Commission State: Office Building 475 Allendale Road Hartford, Connecticut '06106 King of Prussia, Pennsylvania 19406 Bradford S. Chase, Under Secretary Board of Selectmen Energy Division Town Hall Office of Policy and Management Haddam, Connecticut 06103 80 Washington Street Hartford, Connecticut 06106 J. T. Shediosky, Resident Inspector Haddam Neck Plant
. D. B.LMiller, Station Superintendent c/o U. S. Nuclear Regulatory Commission Haddam Neck Plant.
Post Office Box.116 Connecticut Yankee Atomic Power Company '
East Haddam, Connecticut 06423 East Haddam Post Office RFD.1, Post Office Box 127E East Hampton, Connecticut 06424 G. H. Bouchard, Unit Superintendent Haddam Neck Plant
.RFD #1 Post Office Box 127E East Hampton, Connecticut 06424 f
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4 Mr. Mroczka.
situation should arise, it is generally more effective to inject makeup water into the hot leg rather than the cold leg. When using gravity drain from the RWST a proper means for venting must be in place and verified by calculations (see next item).
5.
You indicate that gravity feed from the refueling water storage tank (RWST) is a possible source for makeup to the RCS. You have not stated any specific opening to relieve pressure. The removal of a pressurizer manway or steam generator manway for example, is a means to provide RCS venting. Calculations need to be performed to verify the effectiveness of RCS openings, however, because even for relatively large hot side openings in the RCS, pressurization to several psi can still result. For example, with removal of a pressurizer manway large steam flows in combination with flow restrictions in the surge line and lower pressurizer hardware may still lead to pressurizati0n.
This closes out the staff review of your responses to the expeditious actions listed in the GL. The area of programmed enhancements will be addressed in a separate letter.
If you have any questions please call me at (301) 492-1313.
Sincerely, c
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Alan B. Wang, Project Manager Project Directorate I-4 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation cc: See next page DISTRIBUTION
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