ML050630574
| ML050630574 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 08/08/2005 |
| From: | Dave Solorio Plant Systems Branch |
| To: | Gramm R NRC/NRR/DLPM/LPD4 |
| Whitney L, NRR/DSSA/SPLB, 415-3081 | |
| References | |
| TAC MB9562 | |
| Download: ML050630574 (6) | |
Text
August 8, 2005 MEMORANDUM TO: Robert A. Gramm, Chief Section, LPD IV-2 Project Directorate IV Division of Licensing Project Management Office of Nuclear Reactor Regulation FROM:
David L. Solorio, Chief /RA/
Balance of Plant Section Plant Systems Branch Division of Systems Safety and Analysis Office of Nuclear Reactor Regulation
SUBJECT:
CALLAWAY UNIT 1. - CLOSEOUT LETTER FOR BULLETIN 2003-01, POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY SUMP RECIRCULATION AT PRESSURIZED-WATER REACTORS The Plant Systems Branch (SPLB) has reviewed and evaluated the information provided in responses to Bulletin 2003-01 by the licensee for the Callaway Unit 1. SPLB has determined that the licensees actions have been responsive to and meet the intent of Bulletin 2003-01.
The attachment to this letter provides input to be used in a formal closeout letter to the licensee.
If you have any questions, please contact Leon Whitney or Alan Wang. Please include Alan Wang and Leon Whitney on the distribution list.
Docket Nos:
50-483
Attachment:
As stated CONTACTS: Leon Whitney, SPLB/DSSA 415-3081 Alan B. Wang, DLPM, PD IV 415-1445
ML050630574 NRR-001 OFFICE DSSA/SPLB DSSA/SPLB DLPM/PDIV-2/PM NAME LWhitney DSolorio AWang DATE 07/ 29 /2005 08/ 04 /2005 08/ 08 /2005
ATTACHMENT AmerenUE PO Box 620 Fulton, MO 65251
SUBJECT:
CALLAWAY PLANT UNIT 1 - RESPONSE TO NRC BULLETIN 2003-01, POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY SUMP RECIRCULATION AT PRESSURIZED WATER REACTORS (TAC NO. MB9562)
Dear Mr. Gallegher:
This letter acknowledges receipt of your response dated August 8, 2003, to Nuclear Regulatory Commission (NRC)Bulletin 2003-01, Potential Impact of Debris Blockage on Emergency Sump Recirculation at Pressurized Water Reactors, dated June 9, 2003. The NRC issued Bulletin 2003-01 to all pressurized-water reactor (PWR) licensees requesting that they provide a response, within 60 days of the date of Bulletin 2003-01, that contains either the information requested in following Option 1 or Option 2 stated in Bulletin 2003-01:
Option 1:
State that the emergency core cooling system (ECCS) and containment spray system (CSS) recirculation functions have been analyzed with respect to the potentially adverse post-accident debris blockage effects identified in the Discussion section, and are in compliance with all existing applicable regulatory requirements.
Option 2:
Describe any interim compensatory measures that have been implemented or that will be implemented to reduce the risk which may be associated with potentially degraded or nonconforming ECCS and CSS recirculation functions until an evaluation to determine compliance is complete. If any of the interim compensatory measures listed in the Discussion section will not be implemented, provide a justification. Additionally, for any planned interim measures that will not be in place prior to your response to this bulletin, submit an implementation schedule and provide the basis for concluding that their implementation is not practical until a later date.
You provided an Option 2 response.
Bulletin 2003-01 discussed six categories of interim compensatory measures (ICMs):
(1) operator training on indications of and responses to sump clogging; (2) procedural modifications if appropriate, that would delay the switchover to containment sump recirculation (e.g., shutting down redundant pumps that are not necessary to provide required flows to cool the containment and reactor core, and operating the CSS intermittently); (3) ensuring that
Mr. Gallegher 2
alternative water sources are available to refill the RWST or to otherwise provide inventory to inject into the reactor core and spray into the containment atmosphere; (4) more aggressive containment cleaning and increased foreign material controls; (5) ensuring containment drainage paths are unblocked; (6) ensuring sump screens are free of adverse gaps and breaches.
You stated in your bulletin response of August 8, 2003, that you had implemented the following ICMs:
(1) ensuring that alternate water sources are available to provide inventory to the Reactor Coolant System (RCS) - ICM category #3; (2) ensuring that containment drainage paths are unblocked - ICM category #5; (3) the establishment of required reading for operations personnel on NRC Bulletin 2003-01 and ICMs taken and planned at Callaway as a result of Bulletin - ICM category #1; and (4) an administrative increase in the minimum Refueling Water Storage Tank (RWST) level from 93.6 percent to 97 percent - ICM category #3.
You also stated in your response that you would be implementing the following ICMs:
(1) operator training on indications of and response to sump clogging (by December 31, 2003)
- ICM category #1; (2) additional plant specific training for outage contractor and plant personnel to increase awareness of sump blockage issues (prior to the spring 2004 refueling outage) - ICM category
- 1; (3) training for Technical Support Center (TSC) engineering staff of the Emergency Response Organization on the parameters which would indicate that recirculation sump blockage may be developing, and what mitigating actions should be considered (by the first quarter of CY 2004) -
ICM category #1; (4) more aggressive containment cleaning and increased foreign material controls, including targeting of horizontal surfaces that are not usually accessed (by December 31, 2004) - ICM category #4; (5) procedure changes to ensure that containment drainage paths are unblocked and that radiation barrier gates at the four secondary shield wall entrances are not blocked with debris (by October 31, 2003) - ICM category #5; (6) ensuring sump screens are free of adverse gaps and breaches (during any Mode 5 outage prior to the spring 2004, refueling outage, or prior to plant restart following the spring 2004, refueling outage, whichever comes first) - ICM category #6.
You further stated in your response, including justifications, that you would not be implementing the following ICMs: procedural modifications that would delay the switchover to containment sump recirculation, stating that potential Westinghouse Owners Group (WOG) Emergency
Mr. Gallegher 3
Response Guidelines (ERGs) changes would be evaluated as part of an Owners Group program [resulting in March 2004, in a WOG report WCAP-16204," which provided 11 candidate operator actions (COAs) as ICMs for Bulletin 2003-01].
In a July 9, 2004, response to a April 26, 2004 NRC request for additional information (RAI) you discussed a revision to its original Bulletin 2003-01 response stating that secondary shield wall radiation barrier doors actually would be removed as an ICM until an engineering evaluation can be conducted to determine the impact the doors may have on blocking containment drainage paths - ICM category #5.
In your RAI response you also stated that the following WOG WCAP-16204 COAs would be fully implemented at Callaway, including completion of all necessary training cycles, contingent on acceptable engineering evaluations and simulator validation:
(1) COA 1A - operator action to secure one spray pump before recirculation alignment (by April 29, 2005) - ICM category #2; (2) COA 5 - refill of RWST after switchover to recirculation (by April 29, 2005) - ICM category
- 3; (3) COA 7 - more aggressive cooldown and depressurization guidance (at the Technical Specification limit) for a small break LOCA (implemented by existing procedures) - ICM category #2; (4) COA 8 - Provide guidance on symptoms and identification of containment sump blockage (by April 20, 2005) - ICM category #1; and (5) COA 9 - Develop contingency actions to be taken in response to containment sump blockage (by April 29, 2005) - ICM category #1.
In your RAI response you further stated that the following WOG WCAP-16204 COAs, with justifications, would not be implemented at Callaway:
(1) COA 1B, Operator action to secure both spray pumps before recirculation alignment (potentially exceeding containment temperature and pressure limits);
(2) COA 2 - Manually establish one train of containment sump recirculation prior to automatic recirculation swapover (potential operator errors due to higher tempo of operator actions);
(3) COA 3 - Terminate one train of safety injection afer recirculation alignment (increased potential for ECCS flow single failure);
Mr. Gallegher 4
(4) COA 4 - Early termination of one RHR pump prior to recirculation alignment (applicable only to CE designed plants, unlike Callaways Westinghouse design);
(5) COA 6 - Injection of more than one RWST volume or alternate water source bypassing RWST; (6) COA 10 - Termination of one train of HPSI prior to recirculation (applicable to CE plants only, unlike Callaways Westinghouse design); and (7) COA 11 - Prevent containment spray for small break LOCAs (applicable only to ice-condenser containments, unlike Callaways large, dry containment).
However, for COA 6, on July 28, 2005, David Shafer of your staff provided amplifying information by email to the effect that RCS injection from a refilled RWST is in Step 8 of ECA-1.3, and that direct RCS injection from the volume control tank (VCT) is in Steps 28 and 34 of ECA-1.3 - ICM category #3.
Finally, in your RAI response you provided additional detail on the process for implementing COA operator actions and associated training efforts.
The NRC staff has considered your Option 2 response for compensatory measures that were or were to have been implemented to reduce the interim risk associated with potentially degraded or nonconforming ECCS and CSS recirculation functions. Based on your response, the NRC staff considers your actions to be responsive to and meet the intent of Bulletin 2003-01. Please retain any records of your actions in response to Bulletin 2003-01, as the NRC staff may conduct subsequent inspection activities regarding this issue. NRC staff may conduct subsequent inspection activities regarding this issue.
Should you have any questions, please contact me at 301-415-[xxxx] or the lead PM for this issue, Alan Wang at 301-415-1445.
Sincerely,
[Name], Project Manager, Section [1 or 2]
Project Directorate [I, II, III, or IV]
Division of Licensing Project Management Office of Nuclear Reactor Regulation cc: See next page [Plant Mailing List]
ADD TO DISTRIBUTION: AWang, RArchitzel, DSolorio, MKowal, LWhitney