ML061210317
| ML061210317 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 04/18/2006 |
| From: | David Helker AmerGen Energy Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 2130-06-20314 | |
| Download: ML061210317 (7) | |
Text
Amer(;en Energy Company, LLC www.exeloncorp.com An Exelon Company 200 Exelon Way Kennett Square, PA 19348 10 CFR 50.54 (q)
Apri 18, 2006 2130-06-20314 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Oyster Creek Generating Station Facility Operating License No. DPR-16 NRC Docket No. 50-219
Subject:
Response To Request For Additional Information - Revision of Emergency Plan Emergency Action Levels HA5 and HU5 This letter provides additional information in response to NRC draft request for additional information received via NRC email, dated March 28, 2006, regarding Oyster Creek Revision of Emergency Plan Emergency Action Levels HA5 and HU5, submitted to NRC for review on January 24, 2006. The additional information is provided in Enclosure 1. The revised Bases for the proposed Emergency Action Levels HA5 and HU5 are provided in Enclosure 2. The revised Bases pages provided in Enclosure 2 replace the corresponding pages previously submitted on January 24, 2006.
No new regulatory commitments are established by this submittal. If any additional information is needed, please contact David J. Distel at (610) 765-5517.
Respectfully, David P. Helker Manager-Licensing
Enclosure:
(1) Response to Request for Additional Information (2) Revised Bases for EAL HA5 and HU5 cc:
S. J. Collins, USNRC Administrator, Region I G. E. Miller, USNRC Project Manager, Oyster Creek M. S. Ferdas, USNRC Senior Resident Inspector, Oyster Creek File No. 05045 rqflie Ival le 14711e.
ENCLOSURE 1 OYSTER CREEK RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION Revision of Emergency Plan Emergency Action Levels HA5 and HU5
OCGS Response to RAI - Revision of Emergency Plan Emergency Action Levels HA5 and HU Page 1 of 2
- 1.
NRC Question HU5 and HA5 do not specifically state how the MSL value is read or how to respond when the MSL value cannot be read (canal iced over, etc.). The EAL or EAL basis needs to state how the MSL value is obtained and any restrictions there may be on using this level indication.
Response
The abnormal intake level instrumentation referenced in the EAL and associated Basis (P1-533-1172 and P1-533-1173) consists of bubbler gauges and is read in psig. The Oyster Creek Abnormal Station Procedure, ABN-32, "Abnormal Intake Level," provides a table that converts the psig values to Mean Sea Level (MSL). In addition, the EAL itself lists the psig value corresponding to the MSL EAL threshold. The canal staff gauge, which directly indicates MSL, is not the primary instrument used or referenced in the EAL threshold. There are no restrictions with using the bubbler gauges.
- 2.
NRC Question HU5 and HA5 do not address the P1-533-1172/73 instruments in the EAL basis. The EAL basis should discuss these instruments, any restrictions, and a brief explanation of the need for both indicators to be used for EAL declaration.
Response
As discussed during a telecon with NRC on April 6, 2006, the HU5 and HA5 EAL Basis is revised to provide the following information (noted in bold):
Threshold value HU (Unusual Event)
Both pressure gauges listed (Pi-533-1172 hid 1173) are located inside each of the intake structure bays; they should both be considered to determine the overal 'effect on plant operations due to water level changes,csince be isolated or have its associated screens'clogged reulting in a 1ow intake level 6ondition" on one side of the intake str6cture an'd therefore not provide: positive indication of actual water level trend.
Low Intake Level, <-3.0 feet MSL (P#-533-1172 and 173) indicates the impending loss of vital cooling equipment. This event will be escalated to an Alert based upon water level dropping to s-4.0 feet MSL.
High Intake Level, >4.5 feet MSL (P1-533-1 172 and i.173) is sufficiently high to require plant shutdown per the Abnormal Intake Level Procedure. This event will be escalated to an Alert classification based on water level reaching the elevation of the Intake Structure lower deck.
Threshold HA (Alert)
Both press-e, gauges 'listed (Pi-533-'172 arid 1173) 'are located inside 'each of the intak'e structure bays; they should both be cbrigidered to determine the overall effect on' plant operations due to water level chranges,'since one structure could be isolated or have its associated screen's clog'ged resulting in a lo'w'intake level condition on'onne side of the intake structure and therefore not provide positive indication of actual water level trend.
OCGS Response to RAI - Revision of Emergency Plan Emergency Action Levels HAS and HU Page 2 of 2 Low Intake Level, <-4.0 feet MSL (P1-533-%1172 and 1173) indicates the potential loss of Emergency Service Water Pumps. The Abnormal Intake Level Procedure requires a plant shutdown at this level and requires declaring the affected Emergency Service Water System(s) inoperable. Additionally, the water supply to the primary heat sink (i.e., Circulating Water Pumps) would be jeopardized and component-cooling water, via Service Water and Radwaste Service Water would also be threatened. The primary concern is adequate water level in the Intake Structure.
High Intake Level, >6.0 feet MSL (Pl-533-1172 and 11i3) is capable of causing flooding that can affect Plant Vital Structures. The Abnormal Intake Level Procedure requires a reactor scram at this level. The top of the concrete deck behind the Traveling Screens is +6.0 feet MSL. At levels
>6.5 feet MSL, Circulating Water Pumps may become flooded. At levels >8.0 feet MSL, Emergency Service Water, Service Water and New Radwaste (NRW) Service Water Pumps may become flooded. No attempt should be made to determine the magnitude of flooding. This is a long lead-time event but this level is at the intake structure lower deck so classification of an Alert Event is appropriate. The evidence of flooding is sufficient for declaration.
ENCLOSURE 2 OYSTER CREEK RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION Revised Bases for Emergency Plan Emergency Action Levels HA5 and HU5 Revised Pages D-118 D-121
J3ART II: Planning Standards And Criteria Exelon / AmerGen Table D-2: OCNS EATL Technical Basis RECOGNITION CATEGORY (H)
HAZARDS AND OTHER CONDITIONS HA5 - Cont'd 3ASIS-Cont'd Ti' Threshold Value 4 - This criteria address crashes of vehicles that have caused damage to Plant Vital Structures, and thus damage may be assumed to have occurred to safe shutdown systems. No attempt should be made to assess the magnitude of damage to Plant Vital structures prior to classification. The evidence of damage is sufficient for declaration. A Xvehicle crash includes aircraft and large motor vehicles, such as a crane.
Threshold Value 5 - Both pressure gauges listed (PI-533-1172 and 1173) are located inside each of the intake structure bays; they should both be considered to determine the overall effect on plant operations due to water level changes, since one structure could be isolated or have its associated screens clogged resulting in a low intake level condition on one side of the intake structure and therefore not provide positive indication of actual water level trend.
IHigh Intake Level, > 6.0 feet MSL (PI-533-1172 and 1173) is capable of causing flooding that can affect Plant Vital Structures. The Abnormal Intake Level Procedure requires a reactor scram at this level. The top of the concrete deck behind the Traveling Screens is
+6.0 feet MSL. At levels > 6.5 feet MSL, Circulating Water Pumps may become flooded.
AJt levels > 8.0 feet MSL, Emergency Service Water, Service Water and New Radwaste (NRW) Service Water Pumps may become flooded. No attempt should be made to c.etermine the magnitude of flooding. This is a long lead-time event but this level is at the iitake structure lower deck so classification of an Alert Event is appropriate. The evidence of flooding is sufficient for declaration.
Low Intake Level, < -4.0 feet MSL (PI-533-1172 and 1173) indicates the potential loss of Emergency Service Water Pumps. The Abnormal Intake Level Procedure requires a plant shutdown at this level and requires declaring the affected Emergency Service Water System(s) inoperable. Additionally, the water supply to the primary heat sink (i.e.,
circulating Water Pumps) would be jeopardized and component-cooling water, via Service Water and Radwaste Service Water would also be threatened. The primary concern is adequate water level in the Intake Structure. Once the Circulating Water Pumps are secured, per the Abnormal Intake Level Procedure, sufficient water flow would be expected to be available to the ESW pumps, even if the screens were clogged.
This event will be escalated to a higher emergency classification based upon damage consequences covered under other various EAL Sections.
January 2006 D-1 18 EP-OC-1010 (Revision 5)
PART II: Planning Standards And Criteria Exelon / AmerGen Table D-2: OCNS EAL Technical Basis RECOGNITION CATEGORY (H)
HAZARDS AND OT[IER CONDITIONS HU5 - Cont'd lBASIS: - C t'E Threshold Values 2 & 3 - A tornado touching down within the Protected Area or sustained wind speeds > 75 mph within the Owner Controlled Area are of sufficient velocity to have the potential to cause damage to Plant Vital Structures. The value of 75 mph was selected tb coincide with the Beaufort Scale for Hurricane wind speed winds of 73-136 mph. These criteria arc indicative of unstable weather conditions and represent a potential degradation in the level of safety of the plant. Verification of a tornado will be by direct observation and reporting by station personnel. Verification of sustained (2 15 minutes in duration) wvind speeds > 75 mph will be via meteorological data in the control room. This event will be escalated to an Alert if the tornado or high wind speeds result in damage to Plant Vital structures.
Threshold Value 4 - This criterion is intended to address such items as plane, helicopter, or train crash that may potentially damage plant structures containing functions and systems required for safe shutdown of the plant. If the crash is confirmed to affect a plant vital area structure, the event may be escalated to an Alert classification.
Threshold Value 5 - This criterion is intended to address main turbine rotating component failures of sufficient magnitude to cause observable damage to the turbine casing or to the seals of the turbine generator. Of major concern is the potential for leakage of combustible fluids (e.g., lubricating oils) and gases (e.g., hydrogen) to the plant environs.
Actual fires and flammable gas build up are appropriately classified via other EALs.
Turbine failure of sufficient magnitude to cause observable damage to the turbine casing cr seals of the turbine generator raises the potential for leakage of combustible fluids and gases (Hydrogen cooling) to the Turbine Building. The damage should be readily cbservable and should not require equipment disassembly to locate.
Threshold Value 6 - Both pressure gauges listed (PI-533-1172 and 1173) are located inside each of the intake structure bays; they should both be considered to determine the overall effect on plant operations due to water level changes, since one structure could be isolated or have its associated screens clogged resulting in a low intake level condition on one side of the intake structure and therefore not provide positive indication of actual water level trend.
High Intake Level, > 4.5 feet MSL (PI-533-1172 and 1173) is sufficiently high to require plant shutdown per the Abnormal Intake Level Procedure. This event will be escalated to an Alert classification based on water level reaching the elevation of the Intake Structure lower deck.
Low Intake Level, < -3.0 feet MSL (P1-533-1172 and 1173) indicates the impending loss of vital cooling equipment. This event will be escalated to an Alert based upon water level dropping to < -4.0 feet MSL.
J anuary 2006 D-121 EP-OC-1010 (Revision 5)