ML20211M391
| ML20211M391 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 11/28/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20211M389 | List: |
| References | |
| NUDOCS 8612170197 | |
| Download: ML20211M391 (11) | |
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'/ 'g UNITED STATES 8 o NUCLEAR REGULATORY COMMISSION W I wash:NGTON, D. C. 20665
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SAFETY EVAt.UATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATING TO THE DEFERMENT OF NRC REQUIRED MODIFICATIONS FROM THE CYCLE 11R OUTAGE GPU NUCLEAR CORPORATION JERSEY CENTRAL POWER AND LIGHT COMPANY OYSTER CREEK NUCLEAR GENERATING STATION DOCKET NO. 50-219
1.0 INTRODUCTION
By letter dated July 26, 1985, GPU Nuclear (the licensee) requested the staff to consider the deferment of eight NRC required modifications from the Cycle 11 Refueling (Cycle 11R) outage for Oyster Creek Nuclear GeneratingStation(0ysterCreek). These modifications are the following:
(1) safety parameter display system (SPDS) implementation (2) isolation condenser makeup pump, wall modifications, (5)(3) intake torus canalpiping attached levelsupports instrumentation, (4)require that do not masonry a plant shutdown, (6) torus bulk water temperature indication (7) thermal overload protection for motors for motor-operated valves and [8) airborne particulate and gaseous radioactivity monitors.
The staff, in its letter dated October 6,1986, approved the defement from the Cycle 11R outage of the following modifications listed above:
SPDS, masonry wall, torus attached piping supports, torus bulk water temperature indication and airborne radioactivity monitors. These are items (1),(4),(5),(6)and(8)listedabove. Item (7), deferral of the ,
thermal overload protection modifications, was withdrawn by the licensee.
Items (2) and (3), isolation condenser makeup pump and intake canal level instrumentation, respectively, are the subject of this evaluation.
2.0 DISCUSSION The licensee explained, in its letter dated July 26, 1985, that the intent of the deferments was for the licensee to complete the important safety work in the Cycle 11R outage with the resources available, to manage the outage as best as possible and to restart Oyster Creek within a reasonable time. The licensee explained that the development of the outage plan shows large blocks of work which are of high priority. This includes completion of all Appendix R Fire Protection modifications, which is the largest single plant modification project; a series of activities to enhance the ability of the plant to be less susceptible to intergranular stress corrosion cracking (IGSCC); substantial work in the Control Room Y b b $ PDR P
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including computer hardware installation; and a number of other modifica-tions throughout the plant. The licensee stated that, as the planning developed for the refueling outage, it became apparent that the proposed work scope was exceeding prudent manageability guidelines and would extend the planned outage duration.
The licensee concluded, for a number of reasons identified below, that the work scope must be restrained. In considering restraint of work scope, the licensee explained that it has generally placed highest priority on issues providing maximum safety and operability return, providing maximum assurance of minimizing future IGSCC pipe cracking, and reducing worker radiation exposure on a number of other major activities. Even so, the preliminary outage plan contemplates an outage length from potentially six to nine months long, a peak craft work force of 550 personnel, a total contractor work force of approximately 800 and a projected total ~
man rem exposure estimate of about 850. The planned work still consists of 30 total modification projects and a maintenance effort of over 3,000 individual items, including 110 major activities. Even with the proposed restraint in work scope, the Cycle 11R outage for Oyster Creek is the second longest outage planned for the station. It is exceeded only by the Cycle 10 refueling outage.
The licensee stated that the proposed Cycle 11R work scope limitation will enhance its ability to manage the planned work through improved ,iob super-vision, minimize what might otherwise be unsafe congestion in the Control Poom Drywell and 480V Switchgear Room and allow it to better control radiation exposure. There still remains an inherent risk of work scope growth during the outage because of a large number of inspections to be undertaken (recirculation loop piping, isolation condenser piping, reactor internals, reactor feedwater nozzles, etc.) which have the poten-tial for requiring corrective action.
To contain the work scope and improve outage manageability, the licensee has requested deferment of the eight modifications listed above in that these modifications be completed in the following operating cycle or refueling outage. The licensee's assessment of these eight items is that no significant safety risk is involved.
3.0 EVALUATION 3.1 Introduction _
The plant Oyster Creek was reviewed in the staff's Systematic Evaluation program (SEP). This program was initiated by NRC to review the designs of older operating nuclear reactor plants, as Oyster Creek, to reconfinn and document their safety against current review criteria in 137 different areas defined as " topics." The intearated Plant Safety Assessment Report (IPSAR) for Oyster Creek NUREG-0822, was the first report on the staff review of the plant against this criteria.
NUREG-0822 was issued January 1983.
Section 4.1 of the IPSAR is concerned with the SEP Topic II-3.B. Flooding Potential and Protection Requirements; Topic II-3.B.1, Capability of Operating Plants to Cope with Design Pasis Flooding Conditions, and Topic II-3.C In Section 4.1(1), Safety-Related Water the staff stated that twoSupply (Ultimate condensate pumpsHeat Sink). essential considered to add water to the two emergency Isolation Condensers with cooling water during a hurricane-induced flood are powered from the same engineered-safety-features bus and, thus, a single failure would disable both pumps.
This issue is related to SEP Topic III-4.A, Tornado Missiles, for which in Section 4.6(4) of the IPSAR, the staff stated that redundancy of un-protected pumps is not acceptable protection against tornado missiles.
The service and emergency service water pumps are located adjacent to each other at the intake structure, are located outside and are vulnerable to tornado missiles. This applies also to the Condensate Storage Tank which supplies water to the Isolation Condensers. -
To answer the staff's concerns in Sections 4.1(1) and 4.6.(4), the licen-see comitted to provide a portable pump which could be used to supply makeup water to the Isolation Condensers from a protected water supply.
This would provide the water for reactor cooling in the event of a loss of the cooling resulting from tornado missile damage to the pumps and tanks discussed above. The staff concluded that this portable pump and pro-tected water supply was sufficient (1) to alleviate the need for redundant power for the condensate transfer pumps and (2) to compensate for the outdoor unprotected tanks and pumps.
In Section 4.1(3), the staff concluded that the water level instrumentation in the intake canal was inadequate. To answer the staff's concern, the licensee comitted to install an automatic water level gauge in the intake canal with a remote readout in the control room. In section 4.1(5), it was also discussed that this guage and remote readout in the control room provided information to the control room operators which would enable an operator to respond in a timely manner to low water level in the intake canal. This would be water levels near or below the service water pump suction elevation.
The licensee committed to install both the portable pump and the automatic water level gauge in the Cycle 11R outage.
By letter dated July 26, 1985, the licensee requested deferment of these two modifications related to SEP Topics 11-30. II-3C and III-4.A from Cycle 11R outage to operating Cycle 11 which is scheduled to begin in the fall of 1986. These modifications are:
- 1) To provide an isolation condenser make-up pump which is protected from design basis flooding conditions and tornado missiles.
M To provide an automatic water level recording instrument in the intake canal with remote readout.
In its letter dated April 21, 1986, the licensee changed its request to-defer modification 2 above to a request to revise the scope of the :
modification. The licensee requested that the instrumentation '
modification be replaced by administrative centrols to monitor the level ..
of water in the intake canal and to shut down the reactor at a level exceeding 4.5 ft above MSL.
In its letters dated July 26, 1985, and April 21, 1986, the licensee stated that makeup to the isolation condensers is provided by the Conden- s sate Storage Tank through the condensate transfer pumps. The deferment and scope change were discussed in the April and May 1986 *rogfess Review Meeting held on June 16 and 17, 1986 at the plant site. The meeting suninary is dated August 1,1986. .
3.2 Isolation Condenser Makeup Pump -
The licensee has stated that the makeup to the Isolation Condensers is '
from the Condensate Storage Tank (C*T), and the Fire Water Storage Tank (FWST). The latter tank had not been constructed at the time of the review of SEP Topics II-3.B. II-3.C and 111-4./ and, therefore, was 'not included in this review. In addition, the licensee added that the water in the small Demineralized Water Tank (DW1) is available through a tem-porary hose connection. The makeup to the Isolation Concensers from the FWST and DWT is through the CST and the condensate transfer pamps. The '
CST, FWST and DWT are shown in Figure 1 and are outside tanks unprotected from tornado missiles. The pumps are also located outside and the con-densate transfer pumps are on only emergency diesel and can not be loaded on the other diesel. ,
The licensee explained that its emergency procedures require the Isolation Condensers and the CST to be filled whenever high wind conditions exist.
In the meeting on June 16 and 17, 1986, (Ref. 4), the licensee further explained that procedures require a minimum of 20 feet or 250,000 gallons in the CST. The intake tour sheet requires a minimum of 350,000 gallons in the FWST. The high wind conditions for emergency procedure 7000-ABN-3200.31 II) tornado watch or warning, (2) hurricane watch or warning, (3are tornado the following):
funnel cloud in the area and (4) sustained wind speeds greater than 74 mph. This procedure requires the CST to be filled to 43 feet or 537,500 callons and the Isolation Condensers to be filled (50,000 gallons). The licensee stated that it could if needed bring in a fire truck and pump water into the Isolation Condensers using an alternate connection from the fira water main.
However, the staff concludes it is possible that a fire truck, even if readily obtainable, may *:e delayed from reaching the site due to conditions during and after a hurricane. There are no technical specifications on the FWST and the demineralized water tank.
The NRC Project Manager toured the areas surrounding the CST, FWST and DWT. These tanks are outside buildings near the western side of the Turbine Building or near the intake canal. See Figure 1, Site Plan, from the Updated Final Safety Analysis Report. The tanks and pumps to the Isolation Condenser are at plant grade, 23 feet 6 inches MSL. The pumps are in steel frame, metal siding buildings on a concrete mat.
The tanks and their pumps are at plant grade. This is above the probable maximum hurricane flooding level (PMHFL) of 22 feet MSL. Plant grade is 23 feet 6 inches MSL. The pumps are above the PMHFL and should not be flooded out and a fire truck should not be prevented by flooding from being brought onsite.
All the makeup to the Isolation Condenser can supply a volume of water of .
nearly 1 million gallons. This volume is sufficient, by the licensee's calculations, to maintain the reactor in hot shutdown for greater than 10 days. Over half this volume is in the CST itself. Each Isolation Con-denser, when filled, provides sufficient water capacity to condense
. reactor steam for approximately 50 minutes when one condenser is operated or 100 minutes when both are operated, before makeup water to the condensers is reouired (Ref. 3). This time is sufficient for the licensee to take corrective actions to restore submerged or wind damaged components and refill the tanks with temporary pumps and hoses if necessary.
The problems are that the tanks listed above and their pumps including the condensate transfer pump are outside and considered unprotected from tornado missiles. This is for P.he pumps also, although they are in steel frame, metal siding buildings on concrete mats. The walls are only metal siding. The condensate transfer pump are also on only one diesel and a single failure following loss of offsite power could result in no power to these pumps.
The licensee has stated that if it was needed a fire truck could be brought onsite and water could be pumped into the Isolation Condensers.
As discussed above, there is 50 to,100 minutes available from the water in the two Isolation Condensers which should provide sufficient time for the licensee to bring on or have brought on a fire truck to pump water into the Isolation Condensers. If the fire trucks are not available or cannot reach the site, there is an d ternate, safety grade method, to the Isola-tion Condensers, for the licensee to achieve and maintain hot shutdown.
This second method is described in Section 6.3.1.2, Emergency Core Cooling System, of the licensee's Updated Final Safety Analysis Report (FSAR) and also in Section 2.3, Systems Used To Provide Shutdown Capability, in Appendix A to the licensee's Fire Protection Plan submitted August 25, 1986. This alternate method is the use of the electromatic relief valves (EPPN) in the Automatic Depressurization System (ADS). This capability would be used if the Isolation Condensers were not available.
The EMRV are used to reduce pressure in the reactor vessel to a value where the core spray system can be used to cool the core. The core spray system draws water from the torus suppression pool. This pool is located in the basement of the Reactor Building within concrete walls and is considered protected from tornado missiles.
Therefore, based on the above, the staff concludes that operation of Oyster Creek in operating Cycle 11 without the isolation condenser makeup pump is safe. The staff concludes that loss of all the tanks and pumps discussed will not present an undue risk because the licensee has an alternate path (EMRV and suppression pool), which is protected from flood-ing and tornado missiles, to achieve and maintain hot shutdown. While this method is adequate to justify continued plant operation, the pre-ferred cooling method for the long-term should rely on the isolvation con-denser to avoid a rapid depressurization of the vessel. Also, the ADS cannot be operated from the alternate safe shutdown panel. However, the staff concludes that this deferment from Cycle 11R outage to operating Cycle 11, but no later than the restart from the Cycle 12R outage, is acceptable because the plant remains in a safe condition and higher priority safety improvements will be completed during the Cycle 11R outage.
3.3 Intake Canal level Instrumentation In the April 21, 1986, letter, the licensee stated that station procedure 2000-ABN-3200.31 "High Winds" will be revised to require a plant shutdown when the water level at the intake structure cannot be verified to be less than elevation 4.5 ft MSL. This was discussed in the June 16 and 17, 1986, meeting at the site. The high wind conditions which would have the licensee enter this procedure are discussed in Section 3.2 above and are acceptable to the staff. The NRC Project Manager toured the intake struc-ture to see the vertical column used to measure the intake water level.
The column is easily visible for determining the water level. The NRC Project Manager verified that this shutdown reouirement had been added to Procedure 2000-ABN-3200.31.
This requires continuing surveillance of the existing staff gage with personnel in communication with the control room once the wind conditions are high enough to have the licensee use the above emergency procedure and the water level may begin to increase due to a storm's approach. If personnel cannot be dispatched to keep the staff gage under surveillance, or if communication between the control room and the staff aaae surveil-lance crew is lost, the licensee stated that the plant will' be shut down.
Therefore, the staff concludes that the modification in procedure 2000-ABN-3200.31 meets the intent of Section 4.1(3) of the IPSAR.
The licensee did not provide information on the administrative controls to monitor the intake canal water for low water level in the canal. This would be water levels near or below the service water pumo suction elevation. These administrative controls should explain the conditions whereby low water level would be monitored and the actions to be taken by the control room operators.
The staff concludes that a deferment of installing this equipment in the current Cycle 11R outage is acceptable because the plant remains in a safe condition and higher priority safety improvements will be completed during the Cycle 11R outage. The issue of cancelling the installation of this instrumentation will be addressed later after the staff has reviewed the licensee's administrative controls on monitoring the canal low water level.
3.4 Oyster Creek Long Range planning On November 11, 1985, and February 12, 1986, meetings were held at NRC, Bethesda, Maryland, with the licensee on the licensee's long range program for Oyster Creek. This is the program for Oyster Creek that the licensee uses to identify, plan for, and manage the work to be done in a future -
operating cycle or outage. The staff requested the meeting on November 11, 1985, to understand how the licensee would plan to complete the requested deferments in either operating Cycle 11 or Cycle 12R outage.
The February 12, 1986, meeting was a continuation of the earlier meeting.
The staff's meeting summaries are dated January 23 and March 5, 1986, respectively. In the meetings, the licensee explained the objectives, organization and elements of the long range planning program. This pro-yram began for Oyster Creek in late 1984 at the conclusion of the Cycle 10R outage and has been used to plan for the month long outage in October, November 1985 and current Cycle 11R outage at Oyster Creek. It plans for 5 years into the future.
Based on the disexsic:.s in the two meetings, the staff concludes that a long range planning program exists for Oyster Creek and that it should be adequate to plan for and manage the work to be done to complete the few modifications being deferred from the Cycle 11R outage. Therefore, the planning being done by the licensee to complete these requested deferred modifications in either operating Cycle 11 or Cycle 12R outage is acceptable to the staff.
4.0 CONCLUSION
By letter dated July 26, 1985, the licensee requested that the staff consider the deferment of eight required modifications from the Cycle 11R outage. These modifications are the following: SPDS implementation, isolation condenser makeup pump, intake canal level instrumentation, masonry wall modifications, torus attached piping supports, torus bulk water temperature indication, thermal-overload protection for motor operated valves, and containment airborne particulate and gaseous radio-activity monitors. The licensee requested that the above modifications be deferred to operating Cycle 11 or to the Cycle 12R outage.
Table 1 is the list of the deferments and the licensee's schedele to complete the work.
The staff, in its letter dated October 6,1986, approved the deferment from the Cycle 11R outage of the following modifications: SPDS, masonry wall, torus attached piping supports , torus bulk water temperature indication and airborne radioactivity monitors. The deferral of the thermal overload protection modifications was withdrawn by the licensee.
The isolation condenser makeup pump and intake canal level instrumentation, are the subject of this evaluation.
For the intake canal level instrumentation, the licensee's submittal dated April 21,1986, changed the licensee's request for a deferment to a request for cancellation of the licensee's commitment to install automatic water level instrumentation in the intake canal with readout in the control room.
The staff has addressed the isolation condenser makeup pump and canal -
water level instrumentation in Sections 3.2 and 3.3. In the above sec-tions, the staff concluded that it was acceptable for safe plant operation to defer the modification to the operating Cycle 11. Although the licensee requested to cancel the installation of the canal water level instrumentation, it did not provide infomation on the administrative controls for monitoring the canal water for low water level near or below the service water pump suction elevation and the actions to be taken by the control room operators. The issue of cancelling the installation of this instrumentatior, will be addressed later after the licensee has provided this information. This has been discussed with the licensee and it is acceptable to them.
Table 1 lists all the eight requested deferments, the licensee's schedule to complete the work and the conclusions of the staff.
In accepting these deferments, the staff has concluded that it is in agreement with the licensee that the Cycle 11R outage is a major outage with large blocks of work of higher safety priority than the items being deferred. This higher priority work includes completion of the remaining Appendix R Fire Protection modifications, a series of activities to enhance plant piping to be less susceptible to IGSCC, substantial work in the control room and a number of other modifications including work to meet the Mark I containment Order. This is the final basis for the staff accepting the deferments.
The staff also discussed the licensee's long range planning program for Oyster Creek in Section 3.7. The staff concluded that this program should be adequate to plan for and manage the work to be done to complete the few modifications being deferred from the Cycle 11R outage.
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5.0 REFERENCES
- 1. Letter from P. B. Fiedler, GPU Nuclear, to J. A. Zwolinski, USNRC, dated July 26, 1985.
- 2. Integrated Plant Safety Assessment Report for Oyster Creek dated January 1983, Systematic Evaluation Program.
- 3. Letter from P. B. Fiedler, GPU Nuclear, to J. A. Zwolinski, NRC, SEP Topic III-4.A, Tornado Missiles, dated July 3, 1986.
- 4. Letter from P. B. Fiedler, GPU Nuclear, to J. A. Zwolinski, NRC, SEP Topic II-3B Flooding Potential and Protective Requirements, dated April 21, 1986. ,
- 5. Meeting of June 16 and 17, 1986, April and May 1986 Progress Review Meeting, dated August 1, 1986.
- 6. Letter from P. B. Fiedler, GPU Nuclear, to J. A. Zwolinski, USNRC, Fire Protection, dated August 25, 1986.
Principal Contributors: R. Wescott and J. Donohew.
Dated: November 28, 1986
4 Table 1 DEFERMENTS FROM CYCLE 11 REFUELING (CYCLE 11R) OUTAGE Deferment Deferred to: Staff Conclusions j SPDS December 31, 1987 Deferment is acceptable
- Isolation Operating Cycle 11 but no Deferment is acceptable Condenser later than the Cycle 12R Makeup Pump outage.
Intake Canal Operating Cycle 11 but no Deferment is acceptable **
Level later than the Cycle 12R Instrumentation outage Masonry Walls Operating Cycle 11 but Deferment is acceptable
- no later than the Cycle (11 walls) 12R outage Torus Attached Operating Cycle 11 but Deferment is acceptable
- Piping Supports no later than the Cycle that do not re- 12R outage quire a plant shutdown Torus Bulk Water Cycle 12R outage Deferment is acceptable
- Temperature Indication Thermal- Request withdrawn by --
Overload licensee Protection Airborne Cycle 12R outage Deferment is acceptable
- Particulate and Gaseous Radioactivity Monitors
- 5ubject of staff's letter dated October 6, 1986.
- The request for cancellation of installation of this equipment will be the subject of a separate letter to the licensee.
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