ML042880297
| ML042880297 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 09/30/2004 |
| From: | Peter Dietrich Entergy Nuclear Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 2.04.086, GL-03-001 | |
| Download: ML042880297 (13) | |
Text
Entergy Entergy Nuclear Operations, Inc.
Pilgrim Nuclear Power Station 600 Rocky Hill Road Plymouth, MA 02360 Tel 508 830 8899 Pete Dietrich General Manager Plant Operations September 30, 2004 ATTN: Document Control Desk U. S. Nuclear Regulatory Commission Mail Station O-P1-17 Washington, DC 20555-0001
SUBJECT:
Entergy Nuclear Operations, Inc.
Pilgrim Nuclear Power Station Docket No. 50-293 License No.: DPR-35 NRC Generic Letter 2003-01 Control Room Habitability, Initial Summary Actions Report
REFERENCES:
LETTER NO.:
- 1. NRC Generic Letter 2003-01, "Control Room Habitability," dated June 12, 2003.
- 2. Entergy Letter 2.03.095, NRC Generic Letter 2003-02 'Control Room Habitability," 60-Day Response, dated August 6, 2003.
- 3. Nuclear Energy Institute, NEI 99-03, "Control Room Habitability Guidance," Revision 1, March 2003.
2.04.086
Dear Sir or Madam:
Entergy hereby submits the attached report, in response to NRC Generic Letter 2003-01 (Reference 1), as committed in its 60-day response (Reference 2).
The report (Attachment 1) summarizes the results of the initial "one-time" actions outlined in Section 3 of NEI 99-03, Revision 1 (Reference 3). These initial actions provide the technical and licensing basis for additional actions, such as modifications, tests, technical specification changes, or further analyses. The report addresses subparts 1 (a), 1 (b), and 1 (c), of Generic Letter 2003-01 and summarizes the plans and schedules for the resolution of any significant discrepancies or conditions adverse to quality identified during these initial actions. contains commitments made in this letter.
If you have any qus i
contact Mr. Bryan Ford at (508) 830-8403.
Acting Site Vice President, PNPS MJG/dm 16-
204086
Entergy Nuclear Operations, Inc.
Pilgrim Station Letter Number: 2.04.086 Page 2 of 2 Attachments: 1. Initial Summary Action Report - NRC Generic Letter 2003-01, "Control Room Habitability,"
- 2. Summary of Commitments cc:
Mr. Samuel J. Collins Regional Administrator, Region I U. S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406-1415 Mr. Lee Licata, Project Manager Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop 0-8B-1 Washington, DC 20555-0001 Senior Resident Inspector U. S. Nuclear Regulatory Commission Pilgrim Nuclear Power Station 600 Rocky Hill Road Mail Stop 66 Plymouth, MA 02360 204086 to 2.04.086 Entergy Nuclear Operations, Inc.
Pilgrim Nuclear Power Station Initial Summary Actions Report Response to NRC Generic Letter 2003-01 Control Room Habitability (CRH)
September 30, 2004
TABLE OF CONTENTS 1.0 Introduction 2.0 Summary of Initial Action 2.1 Assemble Control Room Habitability Licensing and Design Bases 2.2 Assemble Control Room Habitability Analyses 2.3 Document Control Room Habitability Licensing and Design Bases and Analyses 2.4 Assess and Evaluate Licensing/Design Bases and Operator Dose Analyses 2.5 Confirm that Limiting DBA has been used to assure adequacy of CRH Design 2.6 Assess and Evaluate Potential Sources of Hazardous Chemicals, Update Hazardous Chemicals Survey as Necessary 2.7 Assess and Evaluate Control Room In-leakage 2.8 Assess and Evaluate Control Room Habitability During Smoke Events 2.9 Assess and Evaluate the Adequacy of Existing Control Room Emergency Ventilation System Technical Specifications 3.0 Response to Generic Letter 2003-01, ftems 1, 2, and 3 3.1 NRC Requested Item 1 3.2 NRC Requested Item 2 3.3 NRC Requested Item 3 4.0 Plan and Schedules 5.0 References Page 2 of 10
1.0
Introduction:
Entergy has followed a systematic approach to assess and evaluate control room habitability (CRH) at Pilgrim Nuclear Power Station (PNPS) using the guidance contained in Section 3 of NEI 99-03, Revision 1 (Reference 1).
The following initial, 'one-time actions" are part of these assessments, as necessary and appropriate. (The corresponding Section of NEI 99-03, Revision 1 is shown in parenthesis.):
Assemble CRH licensing and design bases (3.1.1)
Assemble CRH analyses (3.1.2)
Document CRH licensing and design bases and analyses (3.1.3)
Assess and evaluate licensing/design bases and operator dose analyses (3.2.1)
Confirm that limiting DBA has been used to assure adequacy of CRH design (3.2.2)
Assess and evaluate potential sources of hazardous chemicals.
Update hazardous chemicals surveys as necessary (3.2.3)
Assess and evaluate control room in-leakage (3.2.4)
Assess and evaluate control room during smoke events (3.2.5)
Assess and evaluate the adequacy of existing control room emergency ventilation system tec,nical specifications (3.2.6)
These initial actions provide the technical and licensing basis for additional actions, such as modifications, tests, technical specification changes, or further analyses.
This report summarizes the results of these initial actions, and addresses Section 1, including subparts 1 (a), 1 (b), and 1 (c), of Generic Letter 2003-01.
Section 4 summarizes the plans and schedules.
2.0 Summary of Initial Actions 2.1 Assemble Control Room Habitability Licensing and Design Bases (3.1.1)
PNPS performed a review of the plant licensing basis beginning with the docketed correspondence submitted during the original plant-licensing period.
Subsequent license amendments and commitments made in response to significant plant issues were included in this review. Appropriate sections of the PNPS Updated Final Safety Analysis Report (UFSAR), Technical Specifications (TS), Quality Assurance Policy Document, Control Room Ventilation System Design Criteria Documents, Emergency Plan, and Fire Hazard Analysis were included in the review. Calculations for Design Basis Accident Control Room Dose consequences and additional calculations affecting control room habitability were identified. Plant drawings for the control room envelope, control room heating ventilation and air condition system and various supporting systems and vendor information for major components of the Control Room High Efficiency Air Filtration System (CRHEAFS) were also identified. Pilgrim utilized NEI 99-03 as the guideline for the development of a Topical Design Basis Document (TDBD) under the Design Basis Information Program, which captured the above information.
TDBD-1 10 "Control Room Habitability" (Reference 2) constitutes a comprehensive top-level directory that provides the current plant configuration. It examines both the licensing and design basis issues associated with Control Room Habitability (CRH).
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2.2 Assemble Control Room Habitability Analyses (3.1.2)
Plant documents that capture the CRH Analyses are a subset of the TDBD.
Specific documents identified and assembled include the Design Basis Accident Dose Calculations, the PNPS response to NUREG 0737, Item III.D.3.4, Radiological Events and Toxic Gas Accidents, Individual Plant Examination of External Events and the PNPS Fire Hazards Analysis.
2.3 Document Control Room Habitability Licensing and Design Bases and Analyses (3.1.3)
The listing of documents comprising of the CRH Licensing and Design Basis Analysis, Regulatory Documents, PNPS License Amendments, UFSAR Sections, additional docketed correspondence, station calculations, and system operating and surveillance procedures have been reviewed and incorporated into the TDBD.
2.4 Assess and Evaluate Licensing/Design Bases and Operator Dose Analyses (3.2.1)
PNPS performed a review of the as-built documents for the control room envelope (CRE) and CRHEAFS to ensure the configuration supports and satisfies the design and licensing basis. A review of normal and emergency operating procedures, and system surveillance procedures was conducted to ensure the design and licensing basis is maintained and the system is properly configured prior to being returned to an operable status. A review of station maintenance and modification procedures concluded appropriate administrative controls are in place to ensure the integrity of the control room envelope is maintained. A walk down of the CRE verified the as-built configuration is consistent with the design and licensing basis.
2.5 Confirm that Limiting DBA has been used to assure adequacy of CRH Design (3.2.2)
Radiological analyses considered the DBA-LOCA, Control Rod Drop Accident, and Fuel Handling Accident scenarios. These three analyses envelope all DBAs. The CRH design supports the assumptions and results of the limiting DBAs.
2.6 Assess and Evaluate Potential Sources of Hazardous Chemicals.
Update Hazardous Chemicals Survey as Necessary (3.2.3)
PNPS calculation M-1 037 "Screening Hazardous Materials for Control Room Habitability' (Reference 3) assesses and evaluates the potential hazardous chemicals that could impact CRH. The original design of PNPS did not incorporate specific features to protect control room operators from toxic gasses entering the control room. The CRHEAFS system provided pressurized filtered air to protect the control room from radioactive gasses in the event of a design basis accident, but this system was not designed to provide protection from intrusion of toxic gasses that could pass into the air intake as a result of a nearby industrial or transportation accident.
As part of the TMI Action Plan, the NRC issued NUREG-0737 (Reference 4) containing item III.D.3.4 that required PNPS to:
"...assure that control room operators will be adequately protected against the effects of accidental releases of toxic and radioactive gases and that the nuclear power plant can be safely operated or shut down under design basis accident conditions."
Page 4 of 10
In response to NUREG-0737, PNPS surveyed governmental agencies with jurisdiction over hazardous material storage or transportation in nearby areas. The results of that survey determined that no hazardous chemicals were stored or transported within five miles of PNPS (Reference 5).
PNPS conducted the survey again in late 1992 and determined that some hazardous materials were transported and stored within the five-mile radius.
Based on a detailed analysis, PNPS concluded that control room operators were adequately protected from a postulated hazardous chemical accident (References 6 and 7). Additionally, PNPS has established an annual review of hazardous materials stored and transported within the five miles radius (Reference 8).
Calculation M-1 037 determines the quantities of various hazardous chemicals that may be stored or transported within five miles of PNPS without creating a toxic gas risk to operators in the Control Room. The methodology utilized for this calculation conforms to Regulatory Guide (RG) 1.78 Rev. 1 (Reference 9) which the NRC intends to use in the evaluation of applications for license renewal and for the assessment of Control Room Habitability (Reference 10). This calculation determines the quantities meeting the screening criteria in RG 1.78 for reference use in any future examination of hazardous materials stored or transported within five miles of PNPS. RG 1.78 justifies excluding all hazardous materials stored or transported beyond five miles from PNPS and all hazardous materials stored onsite in quantities up to 100 lbs. This is a conservative summary screening methodology, quantities larger than those established by this calculation may also be acceptable for storage based on more detailed analysis. The evaluation has been updated pursuant to the guidance given in section 3.2.3.2 of NEI 99-03 Rev. 1.
2.7 Assess and Evaluate Control Room In-leakage (3.2.4)
PNPS was scheduled to perform the control room infiltration test in November 2003; however, this test was cancelled due to issues raised concerning the use of alternative source term (AST) in the operability evaluation. Since November 2003, NEI and NRC have provided clarification regarding the use of GL 91-18 (Reference 12) and AST for Control Room Habitability assessment. Accordingly, PNPS is scheduled to perform ASTM E741 testing in February 2005.
A revised operability evaluation of the radiological consequences to control room occupants following a postulated LOCA is being developed using the AST assumptions and methodology provided in RG 1.183. The results of the revised operability evaluations reported in terms of the current licensing basis for PNPS, in terms of dose to the thyroid, whole body, and skin instead of TEDE. PNPS is planning to submit a license amendment request for use of AST. PNPS expects the results of the unfiltered in-leakage values to be bounded by the assumptions supported in the proposed AST license amendment.
2.8 Assess and Evaluate Control Room Habitability During Smoke Events (3.2.5)
As presented in UFSAR Section 10.17, the Main Control Room Environmental Control System (MCRECS) is designed to control the temperature and humidity in the Control Room Envelop (CRE), the Cable Spreading Room (CSR), and the Computer Room (CR). MCRECS normally operates in the re-circulation mode using an economizer to maintain a mix of Page 5 of 10
fresh and re-circulated air to attain a fan inlet temperature of 65F. In order to assess the potential for Control Room Habitability to be affected by smoke, Pilgrim examined the following three different areas where smoke could be generated:
A. Smoke generated inside the plant but outside the MCRECS Environment:
Smoke could be generated in those areas of the plant that are outside the MCRECS environment. The first line of defense against smoke infiltration from these areas is the purge mode of MCRECS. In the purge mode, MCRECS will remove any small quantities of smoke that may migrate into the CRE, the CSR or CR.
The CRE is designed to operate at a slight positive pressure relative to most other areas of the plant. The turbine and reactor buildings in contrast, are designed to operate at a slight negative pressure, hence smoke would flow away from the CRE. In addition, the CRE is surrounded by rated fire walls designed to effectively preclude the passage of fire and smoke in the event of fire in any surrounding area.
The barrier between the CRE and CSR is sealed against the spread of smoke or Halon fire suppression gas. This capability is discussed in Fire Protection Engineering Evaluation 33 (Reference 13) and Pilgrim Letter to the NRC; No. 2.87-196 (Reference 14)
B. Smoke within the MCRECS environment (CRE, the CSR or CR):
Smoke inside the MCRECS environment will activate a smoke detector in the MCRECS exhaust duct. The smoke detector initiates an alarm and automatically places the system into the purge mode. The Control Room Operator can also manually place the MCRECS in purge mode from panel C7 (Reference 15). In the purge mode, AO-N-1 opens the exhaust damper, AO-N-2 closes the ra-circulation damper, and AO-N-3 opens the outside air damper. This alignment supplies the CRE, CSR, and CR with 100% outside fresh air and sends the exhaust airflow outside the building.
Larger quantities of smoke in the CSR or CR will trigger multiple zones of smoke detection, which will activate the respective CSR or CR Halon system. Halon discharge automatically closes the fire dampers in the supply and exhaust ducts for the CSR or CR, shuts down the normal MCRECS supply and re-circulation fans and starts the CRHEAFS supply fans. CRHEAFS provides fresh air to the CRE only.
Evaluations of the floor that separates the CRE from the CSR/CR concluded that the concrete floor, along with the penetration fire and smoke seals, provides an adequate smoke and Halon barrier to the CRE.
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C. Smoke Generated Outside The Building:
A fire or other smoke source outside the process buildings could compromise the CRE environment if the fresh air intake draws smoke into the CRE. Pilgrim has implemented procedural controls to prevent smoke intrusion from the Process Building (Reference 17). The procedure discusses a number of possible fire scenarios, and the CAUTION in Attachment 29 warns that a forest fire may cause a spurious smoke detector alarm (which, as discussed above, places MCRECS into purge mode), or Halon initiation (which activates CHREAFS, and brings in 100% fresh air). This procedure recommends that Operations place the normal HVAC system in a maximum re-circulation configuration to minimize the intake of smoke into the Control and CSR during an external fire.
There are other sections of the procedure addressing fires in other buildings on site, and a PRECAUTION note to operate CHREAFS when smoke can enter the intake plenum; but no other specific actions are defined to protect the CRE from an external incident that would generate large quantities of smoke. The air inlet damper (VD-1 04) has a minimum closed position. It does not fully shut in the recirculation mode so it allows at least some fresh air at all times, even while in "full recirculation mode". Air operators AO-X-3 and X-6 automatically close the air inlet dampers when CHREAFS is activated, but remain in the open position whon CRHEAF system is not running.
Conclusion Smoke detectors in the MCRECS exhaust automatically realign the system dampers to the purge mode, limiting smoke accumulation in the MCRECS environment. Placing MCRECS in purge mode is the first line of defense against smoke that enters the CRE from other areas inside the plant. Maintaining the CRE at a positive pressure, along with existing fire and smoke seals in MCR floor and wall penetrations constitute another level of protection for the operators.
The CRE itself is adequately protected against smoke originating inside the MCRECS environment by either: 1) removing the smoke using the MCRECS purge mode, or 2) switching to the CHREAFS mode of operation if the source is outside of the CRE. The default action for smoke, (or fire) originating inside the CRE, is for the operators to abandon the MCR and staff the Alternate Shutdown Panels. It should be noted that the Control Room is a constantly attended location and any postulated fire would likely be found and extinguished in its incipient stages.
Protection of operators from smoke originating outside the PNPS process buildings depends on entering the re-circulation mode of MCRECS (although securing MCRECS could also be considered).
The ability to completely close down the MCRECS fresh air intake in the re-circulation mode requires a modification to facilitate the manual isolation of AO-X-3 or AO-X-6. ER03120843 was approved to evaluate system improvements.
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2.9 Assess and Evaluate the Adequacy of Existing Control Room Emergency Ventilation System Technical Specifications (3.2.6)
PNPS has a positive pressure CRE. Pilgrim Station Technical Specifications do not contain testing requirement for differential pressuire across the envelope boundary. Pilgrim plans to use the guidance developed by the NEI Technical Specification Task Force and in-leakage test results to determine changes to Technical Specifications if required.
3.0 Response to Generic Letter 2003-01 Items 1, 2 and 3 3.1 NRC Requested Item 1:
Provide confirmation that your facility's control room meets the applicable habitability regulatory requirements (e.g., GDC 1, 3, 4, 5, and 19) and that the CRHSs are designed, constructed, configured, operated, and maintained in accordance with the facility's design and licensing bases.
Emphasis should be placed on confirming:
Item 1 (a):
That the most limiting unfiltered in-leakage into your CRE (and the filtered in-leakage if applicable) is no more than the value assumed in your design basis radiological analyses for control room habitability. Describe how and when you performed the analyses, tests, and measurements of this information.
Response to Item 1 (a):
Pilgrim is planning to perform the unfiltered in-leakage test in February 2005. In the interim, a license amendment for use of AST will be submitted to NRC for approval. The AST calculations use RG 1.183 (Reference 11) guidance and have conservatively assumed an in-leakage of 500 scfm. The test program shall validate the assumed in-leakage magnitude. The AST based calculations supporting the license amendment will confirm that Pilgrim's control room meets the applicable regulatory requirements.
Item 1 (bj:
That the most limiting unfiltered in-leakage into your CRE is incorporated into your hazardous chemical assessments. This in-leakage may differ from the value assumed in your design basis radiological analysis. Also, confirm that the reactor control capability is maintained from either the control room or the alternate shutdown panel in the event of smoke.
Response to Item 1 (b):
The analysis for hazardous chemicals assumes that the system is operating at full capacity in the purge mode with 100% outside fresh air drawn into the CRE. This analysis is very conservative and in-leakage does not apply. Therefore, no further analysis is needed.
Item 1 (c):
That your technical specifications verify the integrity of the CRE, and the assumed in-leakage rates of potentially contaminated air. If you currently have a AP surveillance requirement to demonstrate CRE integrity, provide the basis for your conclusion that it remains adequate to demonstrate CRE integrity in light of the ASTM E741 testing results. If you conclude that your AP surveillance requirement is no longer adequate, provide a schedule for: 1) revising the surveillance requirement in your technical Page 8 of 10
specification to reference an acceptable surveillance methodology (e.g.,
ASTM E741), and 2) making any necessary modifications to your CRE so that compliance with your new surveillance requirement can be demonstrated.
Response to Item 1 (c):
As discussed in item 2.9 above, Pilgrim will propose changes to Technical Specifications, if required, based upon the application of alternate source term, planned in-leakage test results, and the recommendations made by the NEI Technical Specification Task Force.
3.2 NRC Requested Item 2:
If you currently use compensatory measures to demonstrate control room habitability, describe the compensatory measures at your facility and the corrective actions needed to retire these compensatory measures.
Response to Item 2:
Pilgrim does not use compensatory measures to demonstrate control room habitability.
3.3 NRC Requested Item 3:
If you believe that your facility is not required to meet either the GDC, the draft GDC, or the "Principal Design Criteria" regarding control room habitability, in addition to responding to 1 and 2 above, provide documentation (e.g., Preliminary Safety Analysis Report, Final Safety Analysis Report sections, or correspondence) of the basis for this conclusion and identify your actual requirements.
Response to Item 3:
During the construction permit process for PNPS, the unit was evaluated against the original seventy criteria proposed in July 1967, by the AEC (Reference 19). PNPS committed to the intent of the GDC listed in Appendix F of the original UFSAR. By NRC Staff Requirements Memorandum (SRM), NRC Office of the Secretary of the Commission SECY-92-223, issued on September 18, 1992, the Commission approved the staff proposal to not apply the GDC to plants with construction permits issued prior to May 21, 1971. Pilgrim is not a GDC plant, but meets the intent of the GDCs.
4.0 Summary of Plans and Schedules The need for additional plant modifications, revisions of calculations, and procedure changes are deferred until Pilgrim staff has reviewed the results for the in-leakage tests scheduled for February of 2005. If the analyses remain conservative, no update to the items listed above is planned.
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5.0 References 1 NEI 99-03 "Control Room Habitability Guidance" 2
PNPS Topical Design Basis Document -110; Control Room Habitability 3
PNPS Calculation No. M-1 037, Revision 2 4
NRCLE1.1.80.379, Post TMI Requirements (transmitting NUREG-0737),
10/31/1980 5
ELNRC1.2.82.149, Information in Response for NUREG 0737 Item III.D3.4, 5/25/1982 6 SUDDS/RF96-36, BEC-034 Offsite Hazardous Materials Accident Analysis, Rev. 0, 9/17/1996 7
SUDDS/RF96-39, BEC-040 Onsite Hazardous Materials Accident Analysis, 9/16/1996 8
PR98.1886, No Program Was Established After BECo's Response to NUREG-0737, III.D.3.4 CR Habitability Requirements, 6/24/1999 9
Regulatory Guide 1.78, Evaluating the Habitability of a Nuclear Power Plant Control Room during a Postulated Hazardous Chemical Release, Rev. 1, 12/2001 10 GL 2003-01, Control Room Habitability, June 2003 11 NRC Regulatory Guide 1.183 Alternative Radiological Source Terms For Evaluating Design Basis Accidents At Nuclear Power Reactors 12 Generic Letter 91-18 Resolution of Degraded and Non-conforming Conditions/ Operability 13 Fire Protection Engineering Evaluation 33 Cable Spreading Room Ceiling Fire Barriers 14 Edison Letter to the NRC 1.2.87-196 15 Procedure 2.2.46 -Control Room, Cable Spreading Room, and Computer Room Heating, Ventilation, and Air Conditioning 16 Procedure 2.4.149 -Loss of Control Room Air Conditioning 17 Procedure 5.5.2 -Special Fire Procedure 18 Specification M-570 - Fire Barrier and Secondary Containment Seal Systems 19 32FR 10210, USAEC General Design Criteria, 07/10/67 20 Office Memorandum NED 86-504 dated June 10, 1986 21 Letter to the NRC, dated 12/8/87, subject: Control Room Floor, Ref.
ELNRC1.2.87.196 [03651-1323])
22 Drawing M286, Heating Ventilating and Air Conditioning Temperature Control Diagram for Control Room. Cable Spreading & Computer Room Page 10 of 10 to 2.04.086 Summary Of Commitments NRC Generic Letter 2003-01 Control Room Habitability, Initial Summary Actions Report ID No.
Description Date 1
Review the need for additional plant modifications, revisions of site calculations, and 6c days after the procdur chagesreceipt of the final procedure changes results by PNPS of the in-leakage testing.