ML20149M722

Application for Amend to License DPR-22,requesting Authorization for Changes to App A,Clarifying TS 3.5/4.5.C Re Min RHR & RHRSW Pump Requirements for Post Accident & Update of Design Basis Accident Containment & Temp Response

ML20149M722
Person / Time
Site:	Monticello
Issue date:	01/23/1997
From:	Hill W NORTHERN STATES POWER CO.
To:
Shared Package
ML20149M719	List: ML20149M717 ML20149M722 ML20149M728 ML20149M736
References
NUDOCS 9701270117
Download: ML20149M722 (6)

Text

_- . _ - - . . . - -. ._= .

UNITED STATES NUCLEAR REGULATORY COMMISSION NORTHERN STATES POWER COMPANY MONTICELLO NUCLEAR GENERATING PLANT DOCKET NO. 50-263 REQUEST FOR AMENDMENT TO OPERATING LICENSE DPR-22 LICENSE AMENDMENT REQUEST DATED JANUARY 23,1997 Northem States Power Company, a Minnesota corporation, requests authorization for changes to Appendix A of the Monticello Operating License as shown on the attachments labeled Exhibits A, B, and C. Exhibit A describes the proposed changes, describes the reasons for the changes, and contains a Safety Evaluation, a Determination of Significant Hazards Consideration, and an Environmental Assessment. Exhibit B contains current Technical Specification pages marked up with the proposed changes. Exhibit C is a copy of the Monticello Technical Specification pages incorporating the proposed changes. Exhibit D is an engineering report supporting the requested changes.

This letter contains no restricted or other defense information.

NORTHERN STATES POWER COMPANY By M/NAw ] 4 William J HW Plant Manager Monticello Nuclear Generating Plant On this[d y ofbu es Ftt7 before me a notary public in and for said County, personally appeared William J' Hill, Plant Manager, Monticello Nuclear Generating Plant, and being first duly swom acknowledged that he is authorized to execute this document on behalf of Northem States Power Company, that he knows the contents thereof, and that to the best of his knowledge, information, and belief the statements made in it are true and that it is not Interposed for delay.

y  :....... . ..... ... . ..

pk

. SAMUEL 1. SHIREY ,

7 j NOTARY PU8UC - MINNESOTA Samuel i Shirey j , . . - My comm Exp.Jan 31,2000-Notary Public - Minnesota 2 r ^ ^ ^==r=rJr ^J t Sherbume County My Commission Expires January 31,2000 l

I

{

l 9701270117 970123 l

DR ADOCK0500g3

r i f 8 l

i Exhibit A I

MONTICELLO NUCLEAR GENERATING PLANT l

License Amendment Request Dated January 23,1997 l

1 Pursuant to 10 CFR Part 50, Sections 50.59 and 50.90, the holders of Operating License  ;

l DPR-22 hereby propose the following changes to the Monticello Technical Specifications: J Proposed Chanae: l l Revise the Section 3.5/4.5.C Bases on pages 112 and 113 to read:

l C. Containment Spray / Cooling Systems

Two containment spray / cooling subsystems of the RHR system are provided to remove heat energy from the containment and control torus and drywell pressure in the event of a loss of coolant accident. A containment

spray / cooling subsystem consists of 2 RHR service water pumps, a RHR heat l exchanger,2 RHR pumps, and valves and piping necessary for Torus Cooling l and Drywell Spray. Torus Spray is not considered part of a containment spray / cooling subsystem. Placing a containment spray / cooling subsystem into operation following a loss of coolant accident is a manual operation.

l The most degraded condition for long term containment heat removal following l the design basis loss of coolant accident results from the loss of one diesel generator. Under these conditions, only one RHR pump and one RHR service water pump in the redundant division are can be used for containment

! spray / cooling. The containment temperature and pressure have been analyzed l

under these conditions assuming service water and initial suppression pool temperature are both 90 F. Acceptable margins to containment design l conditions have been demonstrated and the containment long term pressure is i limited to less than 5 psig. Therefore the containment spray / cooling system is l more than ample to provide the required heat removal capability. Refer to l USAR Sections 5.2.3.3, 6.2.3.2.3, and 8.4.1.3.

During normal plant operation, the containment spray / cooling system provides l cooling of the suppression pool water to maintain temperature within the limits l specified in Specification 3.7.A.1.

The surveillance requirements provide adequate assurance that the containment spray / cooling system will be operable when required. The head and flow requirements specified for the RHR service water pumps provide assurance that the minimum required service water flow can be supplied to the RHR heat exchangers.

A-1 l

l t

l

\

f

• I l

Reason for Chanae:

l Backaround As discussed in Section 5.2.3.3 and Figures 5-2-14 through 5-2-16 of the original Monticello Final Safety Analysis Report (FSAR), availability of one residual heat removal (RHR) pump and one residual heat removal service water (RHRSW) pump represents the most degraded condition for long term containment heat removal following a loss of coolant accident. This condition occurs on loss of off-site power combined with loss of one diesel generator. The load rating of the remaining diesel generator allows long term operation of only one RHRSW pump and one RHR pump for suppression pool cooling and one Core Spray pump for makeup

, to the reactor.

Following the completion of the Mark l Containment Program, General Electric updated the FSAR containment pressure and temperature response analysis to be consistent with the Monticello Mark l Plant Unique Load Definition. The results of the revised analysis were contained in NEDO-30485, "Monticello Design Basis Accident Containment Pressure and Temperature Response for FSAR Update, December,1983. NEDO-30485 was incorporated in the USAR (which replaced the FSAR in 1982) and was submitted to the NRC to support Monticello License Amendment Request dated May 1,1986 related to containment leakage testing. The amendment request was approved by the NRC and issued as Amendment No.

55 to the Monticello Operating License on November 25,1987.

In 1992, as part of the Monticello Configuration Management improvement Program, inconsistencies were discovered in the assumptions used in NEDO-30485 with respect to the number of operable RHR and RHRSW pumps. A Follow-On item (FOl) was assigned for follow up and assessment of this problem. Assessment confirmed that the NEDO-30485 analysis assumed the availability of two RHR pumps and two RHRSW pumps for containment cooling. General Electric was contacted and requested to revise this analysis.

The revised General Electric analysis, "Monticello Nuclear Generating Plant Design Basis Accident Containment Pressure and Temperature Response for USAR Update," NEDO-32418, December,1994, demonstrated ample margins to containment design limits with one RHR pump and one RHRSW pump available for long-term containment heat removal.

Section 5.2.3.3 of the Monticello USAR was updated with the results of NEDO-32418 and reported to the NRC in the periodic report of changes, tests and experiments in accordance with 10 CFR Part 50.59 on April 20,1995.

Safety System Operational Performance inspection of RHR System A Safety System Operational Performance Inspection (SSOPI) of the Monticello Residual Heat Removal (RHR) System was recently completed by an NRC Region ill inspection team. The exit meeting for this inspection was held on January 8,1997. At this meeting NRC personnel stated that they had identified potential violations of NRC requirements related to the

, containment pressure and temperature analysis described in the Technical Specification l Bases and in the Monticello Updated Safety Analysis Report (USAR).

l A-2

l The NRC inspection team believed the new containment pressure and temperature analysis in NEDO-32418 should have been submitted to the NRC for review and approval prior to being used. The long-term containment heat removal portion of NEDO-32418 used ANS 5.1 (1979) j decay heat power and resulted in a slightly higher suppression pool temperature. The l previous analysis submitted to the NRC was based on the General Electric May-Witt decay l power model.

The inspection team also questioned the meaning of Technical Specification Bases Section 3.5/4.5.C. This section was interprete1 by the inspection team to state that two RHR and two RHRSW pumps are required to perform the containment spray / cooling function. Only one RHR and one RHRSW pump would be available tc pc.rhrm this function in the event of the worst case single failure (loss of a diesel generator with ics: of off-site power).

Purpose of Reauested Technical Specification Chanae The purpose of this submittal is to clarify Section 3.5/4.5.C of the Monticello Technical Specification Bases with respect to the minimum requirements for containment spray / cooling system pumps. Key portions of the wording of this section date back to the original 1970 version of the Monticello Technical Specifications. The wording is confusing and may be in conflict with the original FSAR plant design basis for minimum configuration of containment heat removal equipment.

The proposed wording correctly describes the minimum available RHR and RHR Service Water Pumps with the limiting single failure of a diesel generator.

l Safety Evaluation 1

The proposed change involves a clarification to the Technical Specification Bases in Section 3.5/-l.C C. The proposed wording correctly describes the design basis of the Monticello plant ,

for long ten' wr, ro aoval minimum pump availability. The proposed wording is supported by the General bec% ana;ysh. povided in Exhibit D.

No changes to the physical configuration of the plant or how the plant is operated are proposed.

No changes to the Limiting Conditions for Operation or Surveillance Requirements in Sections 3.5.C or 4.5 C are proposed.

No Sionificant Hazards Considerations:

The Commission has provided standards (10 CFR Section 50.92) for determining whether a significant hazards consideration exists. A proposed amendment to an operating license for a facility involves no significant hazards consideration if operation of the facility in accordance with the proposed amendment would not (1) involve a significant increase in the probability or consequences of an accident previously evaluated; (2) create the possibility of a new or A-3

t .

different kind of accident from any accident previously evaluated; or (3) involve a significant j reduction in a margin of safety.

1 l After reviewing this proposed amendment we have concluded that:

1) The proposed amendment will not involve a sianificant increase in the probability or ,

consecuences of an accident previously evaluated l

These changes do not affect the physical configuration of the plant or how it is l operated. As such, they cannot be the initiator of any plant event and cannot result in the increase in the probability of an event. The changes clarify the Technical l

Specification Bases to correctly describe the design basis of containment spray / cooling equipment following a loss of coolant accident.

t

2) The proposed amendment will not create the possibility of a new or different kind of accident from any accident previousiv analyzed l These changes do not affect the physical configuration of the plant or how it is

operated. Clarification of the Technical Specification Bases to correctly describe the design basis of the containment spray / cooling system cannot cause the possibility of a new or different kind of accident from any previously evaluated.

l The proposed amendment will not involve a sianificant reduction in the marain of 3) i safety i l The proposed change involves NRC Staff review and approval changes to the l Technical Specification Bases and of a revised design basis accident containment pressure and temperature analysis.

l I

Different assumptions and decay heat models are used in the new analysis. Some margins have changed from earlier analyses, but substantial margins of safety i continue to be demonstrated in the new analysis in Exhibit D.

I Based on the above findings, we have determined that the proposed amendment will not J involve a significant hazards consideration. '

Environmental Assessment Northern States Power Company has evaluated the proposed change and determined that:

1. The changes do not involve a significant hazards consideration,

2. The changes do not involve a significant change in the types or significant increase in the amounts of any effluents that may be released offsite, or I

j A-4 l I

l l

_ _ .o

! 3. The changes do not involve a significant increase in individual or cumulative l occupational radiation exposure.

Accordingly, the proposed changes meet the eligibility criterion for categorical exclusion set i

forth in 10 CFR Section 51.22(c)(9). Therefore pursuant to 10 CFR Section 51.22(b), an environmental assessment of the proposed changes is not required.

l t

l l

l t

A-5