ML20151A704
| ML20151A704 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 03/30/1988 |
| From: | Fiedler P GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| RTR-REGGD-01.097, RTR-REGGD-1.097 NUDOCS 8804070202 | |
| Download: ML20151A704 (12) | |
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GPU Nuclear Corporation arsippany, New Je sey 07054 201-316-7000 TELEX 136-482 Writer's Direct Dial Number:
March 30, 1988 U.S. Nuclear Regulatory Comission Attention: Document Control Desk Washington, D.C.
20555 Gentlemen:
Subject:
Oyster Creek Nuclear Generating Station l
Docket No. 50-219 l
GPUN Response to Technical Evaluation Report (TER) i EGG-flTA-7277 l
Re:
Conformance to Regulatory Guide 1.97 l
Your letter to P. B. Fiedler dated September 4,1987 transmitted a technical evaluation report (TER) entitled "Conformance to Regulatory Guide 1.97, Oyster i
Creek Nuclear Generating Station".
The report was prepared by an NRC contractor (EG8G) following their review of our June 13, 1984 and May 9,1986 responses to the conformance of Oyster Creek to Regulatory Guide (R.G.) 1.97, Instrumentation for Light-Water-Cooled Nuclear Power Plants to Assess Plant and Environs Conditions During and Following an Accident, t
l Your letter of September 4,1987 requested that the TER be reviewed and a written response provided to the staff addressing the exceptions taken by GPUN to R.G.1.97 requirements as identified in the conclusion of the TER.
The attached report provides our responses to the concerns raised by the TER.
l Very truly yours, sj dier
~~
Vice President and Director Oyster Creek PBF/YN/pa(6410f) cc's on next page
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'8804070202 890330 Corporabon is a subs,d ary d General Pubhc Ut.1 t es Corporat,on PDR ADOCK 05000219 P
cc: Mr. William T. Russell, Administrator Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA.
19406 NRC Resident Inspector Qyster Creek Nuclear Generating Station Forked River, N.J.
08731 Mr. Alex Dromerick, Jr.
U.S. Nuclear Regulatory Commission Washington, D.C.
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GPUN RESOLUTION OF NRC COMMENTS REG. GUIDE 1.97 SUBMITTAL 1,
Neutron Flux EGaG voment:
Neutron flux--the licensee should upgrade the average power range monitors to Category 1; the licensee should provide independent Class 1E power supplies for the redundant channels of instrumentation (Section
- 3. 3.1 ).
Additionally, the reviewer states that since GPUN plans to take actions based upon the Emergency Operating Procedures (E0Ps) in the event power is greater than 2% or undetemined (an ATWS event), there is a need to make neutron flux a Type A variable.
GPUN Response:
GPUN originally proposed that the neutron monitoring system be designated Type B - Category 2.
GPUN is withdrawing its original position on neutron monitoring.
GPUN along with the BWR Owners Group (BWROG) is re-examining the topic of scram verification.
A BWROG Reg. Guide 1.97 subcomittee has been formed and a report will be issued as a Licensing Topical Report.
GPUN will review the subcomittee report for applicability to Oyster Creek.
Our position will be further clarified after the BWR Owners Group has issued its report.
GPUN disagrees with the argument that any variable monitored while implementing the E0Ps is a Type A variable.
Reg. Guide 1.97 indicates that Type A variables are specifically for mitigation of Design Basis Accident (DBA) scenarios.
ATWS is not a DBA at Oyster Creek.
In a BWR the only possible need for post-accident neutron monitoring is to provide indication of scram failure after a postulated ATWS event.
- However, neutron monitoring cannot be used as a sole indication to establish a permanent reactor shutdown.
2.
Coolant Level in Reactor EG&G Coment:
Coolant level in reactor--the licensee should provide additional infomation on the range and the span that is covered by a single channel; the licensee should provide independent Class lE power supplies for the redundant channels of instrumentation (Section 3.3.2).
Additionally, the reviewer questions whether +180 inches is a sufficient upper range limit and what portion of the range is covered by a single channel.
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.GPUN Response:
Oyster Creek has two different systems (Category 1) with 4 separate channels monitoring reactor water level.
The Fuel Zone Level Monitoring System (FZLMS) Channels AaB and the Reactor Protection System (RPS)
RE05/19 A&B.
The FZLMS is a density compensated water level detection system.that indicates a range of -150 to +180 inches above the Top of Active Fuel (TAF) on two electrically separated channels.
The RPS - level monitoring system consists of two separated safety channels in two divisional systems. The range of these instruments is from +85 to +185 inches TAF.
These instruments are powered from separate 120V AC vital buses which can be powered by either the emergency diesels or the station batteries.
Note 9 of Table II of the original GPUN submittal will be deleted.
Tne upper range limit +185 inches was selected in order to prevent water hammer in the isolation condenser piping which begins at 183 inches, TAF. The isolation condensers are natural circulation steam sinks for the reactor vessel and are used to remove core decay heat in the event the main condenser is unavailable. The centerline of the isolation condenser's steam lines is +188 inches TAF and the centerline of the main steam lines is +238 inches TAF.
The plant operating procedures instruct the operator to terminate all reactor vessel injection if water level rises to 180 inches.
Because the main steam line vessel penetrations are located above the 10 inch diameter isolation condenser steam lines and adequate guidance is given to the operator to maintain water level below the isolation condenser steamlines, the main steam lines should never be reached.
For these reasons the range of the existing, qualified reactor coolant level monitoring system at Oyster Creek is sufficient and acceptable.
3.
Reactor Coolant System Pressure EG&G Comment:
Reactor coolant system pressure--the licensee should provide independent Class 1E power supplies for the redundant channels of instrumentation (Section 3.3.3).
GPUN Response:
Reactor pressure instruments, Rosemount transmitters, are used by the Fuel Zone Level Monitoring System Channels A&B to compensate the reactor Fuel Zone Water Level indication. These wide range, 0-1500 psig, environmentally qualified instruments are displayed in the control room and are powered I;y the independent, vital power supplies of the FZLMS.
Since the existing reactor pressure indicators have independent power supplies, they are acceptable.
Note 9 of Table II will be deleted from the original GPUN Reg. Guide 1.97 submittal.
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4.
Containment Effluent Radioactivity EG8G Comment:
Containment effluent radioactivity--the licensee should show that the range of this instrumentation is adequate for its purpose as listed in the regulatory guide, (Section 3.3.6).
GPUN Response:
At Oyster Creek this variable is monitored by the RAGEMS - Radioactive Gas Effluent Monitoring System.
Recent analysis has shown that the RAGEMS has adequate upper range to detect and measure leakage from the containment following an accident.
Calculations show that maximum expected concentration of radioactive gases in the secondary containment i
i s 9. 2 u Ci /cc.
- This concentration is reduced to 0.35 uCi/cc when air discharged from the Standby Gas Treatment System (SGTS) is released to the plant stack where it is diluted by Turbine Building ventilation and monitored by the RAGEMS. The RAGEMS has a maximum upper range limit of i
196 uCi/cc.
This results in a safety factor of over 500 if dilution is assumed and over twenty in the unlikely event that dilution air is not available.
The low range limit of RAGEMS is approximately 3x10-6 uCi/cc.
This is close to nonnal operating background level at Oyster Creek.
Therefore, the range of the RAGEMS system is sufficient to monitor this variable.
The original GPUN submittal proposed using the SGTS radiation monitoring instrumentation for this variable.
Further investigation has shown that i
use of RAGEMS is a more accurate and appropriate instrument to monitor the containment effluent release to the site boundary.
The original submittal will be revised to delete Note 13 of Table II which discussed the use of the SGTS instrumentation.
5.
Effluent Radioactivity i
EG&G Comment:
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Effluent radioactivity--the licensee should verify that the power supply is suitable for Category 2 instrumentation; the licensee should show that the range of this instrumentation is adequate for itc purpose as listed in the regulatory guide (Section 3.3.6).
GPUN Response:
As discussed in the original GPUN submittal, the RAGEMS will be used to l
measure effluent radioactivity.
The range of RAGEMS is described in l
Response #4, Containment Effluent Radioactivity, and is adequate to l
monitor this variable.
Note 13 Table II will be deleted from that
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submi ttal.
- Based on 10M, of noble gases released into primary containment atmosphere and 1% per day leakage rate from primary to secondary containment.
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C' The RAGEMS is installed in a mild environment building outside secondary containment.
GPUN has completed an engineering package to upgrade the RAGEMS power supply so that the two monitoring channels will have a suitable power supply for Category 2 instrumentation.
The existing RAGEMS equipment with upgraded power supply will be adequate to monitor this variable.
6.
Radiation Exposure Rate EG&G Comment:
Radiation exposure rate--the licensee should show, by analysis, that the instrument range for a given location encompasses the maximum expected radiation level (Section 3.3.7).
GPUN Response:
The original GPUN submittal listed Radiation Exposure Rate as variable C-7 based upon the recommendation of Reg. Guide 1.97, Revision 2.
Revision 3 of Reg. Guide 1.97 deleted Radiation Exposure Rate as a Type C variable and further states that effluent monitors are effective for monitoring potential breach of containment.
As stated in the original GPUN Reg. Guide 1.97 submittal, Radiation Exposure Rate is not a good indicator for measuring secondary containment leakage.
At Qyster Creek effluent monitors are the preferred method.
The original GPUN submittal will be revised to delete variable C-7, Radiation Exposure Rate.
The instrument ranges and maximum expected radiation levels measured by the Radiation Exposure Rate Monitoring system is provided in Response #12, Reactor Building Area Radiation.
7.
Containment Spray Throttling Valve Position EGaG Comment:
Containment spray throttling valve position--the licensee should verify that this instrumentation is Category 2 (Section 3.3.8).
GPUN Response:
Qyster Creek does not have containment spray throttle valves.
8.
Torus Water Temperature EGaG Comment:
Torus Water Temperature--the licensee should provide independent Class 1E power supplies and show that the Category 1 criteria are satisfied for this instrumentation (Section 3.3.9).
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GPUN Response:
GPUN has scheduled installation of a Category 1 torus water temperature monitoring system for the 12R refueling outage, pending availability of qualified components.
This installation is in the preliminary engineering phase.
The design criteria call for a separated two division system with six sensors and an independent power supply in each division.
The sy: tem will be environmentally and seismically qualified with display and trend recording capability in the plant computer.
After modification, Note 9 of Table II of the original GPUN Reg. Guide 1.97 submittal will no longer apply.
9.
Standby Liquid Control System Storage Tank Level EG&G Comment:
Standby liquid control system tank level--the licensee should verify that this instrumentation is Category 2 (Section 3.3.11).
Additionally, the reviewer notes, "The licensee states that this instrumentation will be operating in a MILD ENVIRONMENT and that the current design basis for the SLCS recognizes that the system has a classification less than the importance to safety of the reactor protection system... "
(Note: Boldface by GPUN)
GPUN Response:
Oyster Creek Final Safety Analysis Report discusses the SLCS in Section 9.3.5 as a reactivity control system, a long tenn backup to the Control Rod Scram System.
The SLCS, therefore, is used to mitigate an ATWS event, not Design Basis Accidents (LOCA & HELB).
For this reason, SLCS is not a part of the GP' N Environmental Qualification program.
- Further, J
the SLCS is not required to operate under harsh environmental conditions.
This system is correctly graded as Category 3.
Due to operational problems with the level sensor, GPUN has replaced the original float type sensor with a r.ew, ultrasonic level measuring l
system.
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10.
Cooling Water Temperature To Engineered Safety Features System Components l
Cooling water temperature to engineered safety features system components--the licensee should verify that the containment spray heat exchanger inlet and outlet temperature instrumentation is Category 2, and verify that the containment spray system is the only engineered safety feature that utilizes cooling water (Section 3.3.12).
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GPUN Response:
The only Engineered Safety Feature (ESF) that uses Emergency Service Water is the Containunt Spray System.
The Containment Spray Heat Exchanger inlet temperature will be monitored by the new Torus Water Temperature Monitoring System.
This will be a Category 1 installation.
The Containment Spray Heat Exchanger outlet temperature thermocouples are environmentally qualified.
Thus, the Containment Spray Heat Exchanger temperature monitoring eouipment will meet Category 2 requirements of Reg. Guide 1.97 after the installation of the Torus Temperature Monitoring System.
11.
Status of Standby Power EGSG Comment:
Status of standby power--the licensee should upgrade this instrumentation to Category 2 (Section 3.3.14).
GPUN Response:
The instrumentation and sensors necessary to verify the status of standby power sources are voltmeters and ammeters of the A&B diesels and the B&C batteries.
The scnsors for monitoring these parameters are located in non-harsh environments.
Both A & B diesels are in the emergency diesel generator buildings which remain non-harsh following a postulated HELB or LOCA.
The B battery at Oyster Creek is located in the Office Building.
The C battery is located in a ventilated battery room inside the 4160 volt distribution room.
These are also post accident mild environtnents.
For these reasons these voltmeters and ammeters are not a part of the 10CFR50.49 environmental qualification program at Oyster Creek.
The entire instrument loop is in a mild environment with the exception of the cable which runs through the Turbine Building.
These cables will be considered under the GPUN generic cable qualification program.
For these reasons the existing equipment is sufficient and adequate.
12.
Reactor Building Area Radiation EG&G Comment:
Reactor building area radiation--the licensee should provide additional justification for the exception of the instrumentation for this variable (Section 3.3.15).
Additionally, the reviewer asks that "...the licensee show that the vent stack noble gas effluent monitors cover the equivalent to the recomended 10' to 104 R/hr range".
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GPUN Response:
The RAGEMS as described in Response #6, monitors Reactor Building radiation due to airborne radioactivity.
Airborne contamination is proportional to containment leakage and in a postulated LOCA with design basis containment leakage provides a large component of general area dose.
The calculated peak exposure rate in the reactor building due to radioactive gas following a postulated DBA is approximately 135 R, our.
The RAGEMS high range gas channel with dilution range factor would be able to measure a radioactive gas concentration indicative of a general area radiation exposure rate in the Reactor Building of at least up to 6.73 x 104 R/ hour.
This exceeds the upper range requirements of Reg.
Guide 1.97 for the Design Basis Accident worst case scenario.
The other component of general area radiation is local " t
.e" from accident mitigation equipment.
A combination of portable nigh range l
monitors and permanently installed Area Radiation Monitors will measure l
this component.
The Oyster Creek Area Radiation Monitor (ARMS) detectors ara located throughout the plant and displayed in the Control Room.
Twenty-eight area monitor detectors are located in the Reactor and i
l Turbine Building.
Of these 11 are expected to remain on scale during an accident or be off scale during a short period of no operational significance.
Seventeen of the monitors may be driven off scale by post-6ccident radiation.
The fact tha' these monitors are driven off scale is of little practical significance because containment leakage is being measured by airborne radiation monitors at the plant vent and j
because personnel will not be sent into these areas without suitable portable radiation monitors due to the high radiation levels, t
The current instrumentation is adequate to handle anticipated operational needs for the expected dose rates under various accident <:onditions.
It is also clear that containment leakage will be most clearly seen from the I
monitors in the plant stack as described be?ow and in Response #6.
l 1.
The use of ARMS to detect primary containment breach or leakage, per R.G.1.97, is not only impractical, but also unnecessary.
This is because secondary containment radiation exposure rates would be more a function of radioactivity in the l
primary containment and in the liquids flowing through l
emergency system pipes, resulting in direct radiation shine on i
area monitors.
Also, ARMS would give at the very most, ambiguous indications about potential containment leakage due to the widely scattered location of pipes and number of electrical penetrations.
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2.
High levels or airborne dose rates (beyond the current ARMS range) in the Reactor Building would:
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Preclude access per procedures I
b) Render the reliability of Reactor Building ARM indications l
suspect due to probable contamination of the detectors in the Reactor Building, t
3.
If post-accident airborne dose rates were low enough so as not to preclude access to the Reactor Building, such access would not likely be required to service safety related equipment.
l 4.
Since the Reactor Building would be designated as a Prohibited Access area, accessibility would be re-established by a combination of portable dose ate survey instruments and post accident sampling of the secondary containment atmosphere by l
Radiation Protection personnel. The existing ARMS (typically 4 l
decades lower than the R.G.1.97 range) would be used only after radiation levels were within their range and their reliability had been re-established.
See Table 1 for details of these monitors.
- 13. Stack Noble Gas and Vent Flow Rate EGaG Coment:
Stack noble gas and vent flow rate--the licensee should provide a highly l
reliable power source for this instrumentation.
GPUN Response:
The stack noble gas monitoring and vent flow rate will be provided by the l
RAGEMS system.
As described in Response #5, Effluent Radioactivity, the power supply will be upgraded to meet Category 2 design criteria.
This will satisfy the requirement for a high reliability power source, l
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,e Table 1 Oyster Creek Radiation Monitors Tag No.
Range Maximum Expected Post-No.
mR/hr Location Accident Dose Rate A-1 0.01-100 Entrance to Turbine Bldg.
1000 mR/hr E1. 35' 6" frcm Ad. Bldg.
A-2 0.01-100 Entrance to Control Room
< 240 mR/hr A-3 0.01 -1 00 South Wall of Control Room 50 mR/hr A-4 0.1-1000 Turbine Bldg. E1. 41' 6"
< 300 mR/hr A-6 0.1-1000 Above Turbine Bldg. Lube
< 1000 mR/hr Oil Bay A-7 0.1-1000 Turbine Bldg. Feed Pump 10 mR/hr Area E1. 3' 6" A-8 0.1-1000 Turbine Bldg. Above 20 mR/hr Condensate Pumps A-9 0.1-1000 Turbine Bldg. Bsmt.
> 1000 mR/hr Cond. Demin. Viv. Area i
A-10 0.1-1000 Regeneration Area 71000 mR/hr B-1 0.1-1000 Turbine Bldg. Bsmt.
< 1000 mR/hr Makeup above sample sink Demineralizer B-2 0.1-1000 Turbine Bldg. Bsmt.
<1000 mR/hr Air Comp. Area B-7 0.1-1000 Reactor Bldg. T.I.P.
lx104 R/hr Area, E1. 23' 6" B-8 0.1-1000 Personnel Hatch
- 1. 2x104 R/hr l
D/W Airlock 23' 6" B-9 0.1-1000 Reactor Bldg. Equip.
< 135 R/hr Hatch, El.119' B-10 0.1-1000 Reactor Bldg. Drain
< 200 R/hr Tank Area, E1. 6' 5" i
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Tag No.
Range Maximum Expected Post-No.
mR/hr Location Accident Dose Rate C-1 0.1-1000 Reactor Bldg. Cleanup
< 73 R/hr Pump Area, E1. 51 ' 3" C-2 0.1-1000 Reactor Bldg. Fuel
< 2x104 R/hr Pool Filter Area, E1. 75' 3" C-3 0.1-1000 Emergency Condenser
< 4000 R/hr Area 95' 3" C-4 0.1-1000 Shutdown Hx Area
>1300 R/hr 5' 3" C-5 0.1-1000 Reactor Bldg. Spent
<135 R/hr Fuel Pool, El.119' C-6 0.1-1000 Liquid Poison System
<73 R/hr E1. 95' 3" C-7 0,1-1000 Reactor Bldg. CRDM 6x104 R/hr Area, El. 23' 6" C-8 0.1-1000 Air Ejector Area,
< 3 R/hr Turb. Bldg. E1, 3' 6" C-9 0.1-1000 Reactor Bldg. Fuel
< 135 R/hr Pool Area, El.125' C-10 10-106 Reactor Bldg. Fuel
<135 R/hr Pool Area E1.119' D-1 0.1-1000 Refueling Bridge Note 1
<135 R/hr D-2 0.1-1000 Refueling Bridge Note 1
< 135 R/hr Notes:
1.
The Refueling Bridge Monitors local indication and alarm only, i
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