ML20043B369

Describes Util Current Plans for Removal of Certain Plant Equipment Items.Components to Be Removed Have No Required Nor Useful Function During Planned or Postulated Remaining Defueling or Shutdown Conditions

ML20043B369
Person / Time
Site:	Fort Saint Vrain
Issue date:	05/22/1990
From:	Crawford A PUBLIC SERVICE CO. OF COLORADO
To:	Weiss S Office of Nuclear Reactor Regulation
References
P-90159, NUDOCS 9005290206
Download: ML20043B369 (15)

Text

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I x., ., 1 h#Putslie Service' Eh P.O. Box 840 '

1 Denver CO 80201 0840 s q .. A. Clegg Crawford I May 22..1990 Vice Preesden .;

Nucioet Operations  ;

-port'St[ Vrain.

Unit No. 11 *""""=""-

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U. S. Nuclear Regulatory Commission  ?: W  :

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Washington, D. C, 20555 pg

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. ATTN: .Mr. Seymour.H. Weiss; Director E Non-Power Reactor, Decommissioning and  !! C, ,,,

Environmental '-oject Directorate-  :: = '

= - 1 Docket No. 50-267 ,!! E s

SUBJECT:

- COMPONENT REMOVAL ACTIVITIES h.EE.'

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REFERENCES:

1. PSC'1etter, Crawford to Document Control Desk, dated ,

6/30/89.(P-89228) j

.2.

.PSC- letter, Crawford .to Weiss, dated 4/25/90-(P-90123)~

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Dear Mr.. Weiss:

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This -letter describes Public Service - Company of Colorado's (PSC) ,

current plans for removal of certain: Fort St. Vrain. (FSV) equipment

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items. . ' FSVLdefueling has progressed as far as possible until either?

approval z is received to ship fuel to an off-site facility or until an-on-site. Independent . Spent Fuel Storage . Installation can ~be-constructec. Since neither of these options will be available in the' .

,. near future, PSC is proceeding with the planning, preparation, and '

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initiation of other plant closure activities. ,

u The plant closure act~ivities under consideration include removal of certain~ plant components that have no required nor useful

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u function 1 during any planned or postulated remaining defueling or shutdown

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conditions. Some of these components are spares, and some are

. installed in systems that have been permanently shutdown.

The (Decommissioning Rule (53 FR 24018) requires NRC approval of the c

proposed decommissioning plan before a licensee may. decommission a nuclear facility. ~In the guidance provided with the Rule, the NRC ,

stated that major. changes and major decommissioning procedures may not' be ' performed without an approved decommissioning plan. PSC:

considers that plant closure activities that are not major changes or.

major decommissioning. procedures may be undertaken, prior to NRC /

approval of the proposed decommissioning plan.

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l P-90159 Page 2 May'22, 1990-Based _upon. a_ review of the existing regulations.and the guidance provided with the Decommissioning Rule, PSC considers that ' plant closure activities are within existing licensee authority provided they do not require a change to the FSV Technical. Specifications 'or-Operating License, do not involve an unreviewed. safety question as defined in 10 CFR 50.59, do not have an adverse environmental impact, and do not limit the choice of reasonable'_ decommissioning alternatives (i.e., SAFSTOR, DECON, or . ENTOMB) _ Attacnment 1 includes a list of plant closure activities PSC intends to perform within existing l licensee authority. Attachment 2 includes a-list of plant closure activities which PSC plans to perform but which require a change to the Technical Specifications. Requests to perform the activities in Attachment 2 will be submitted separately for NRC approval.

In- the FSV Preliminary Decommissioning Plan (Reference 1),PSC

. indicated that. component removal activities would generally be performed during the time period from April through October of 1993. .i This_ schedule was based-on shutting the pl ar,t down in June 1990. '

' Fort St. Vrain was actually shut down in August 1989 and- the schedule for plant closure activities has been' reevaluated. As a result of this reevaluation, PSC is proceeding with certain activities at the present time for the following reasons: First, it is: desirable to-perform these ' activities with personnel who are knowledgeable-and-experienced, especially with components and handling devices unique *

<to .FSV. Second, DOE has proposed the removal and post irradiation examination of:'various FSV components in the interest 'of. -technology transfer to the New Produr ion Reactor Modular High Temperature Gas-Cooled Reactor (MHTGR)- (an initial list of these . components is provided in Attachment 3). In- addition, considering the future uncertainties and costs associated with waste disposal, .it= is desirable 'to initiate 'the removal and burial _ of unnecessary radioactive and contaminated FSV equipment. Finally, PSC is concerned: that unnecessary delays in accomplishing plant closure activities that can be safely undertaken in accordance with existing regulatory -authority will extend the FSV decommissioning schedule at a' cost of approximately S2.5 million per month; in our opinion, unnecessary delays will adversely impact PSC's ability to retain quality people and could therefore affect safety.

Each component removal activity that PSC considers to be within existing licensee authority will be evaluated to verify that it does not require a change to the FSV Technical Specifications, involve an unreviewed safety question, have an adverse environmental impact, preclude any reasonable decommissioning alternative, or significantly increase the radiation exposure required for decommissioning. These and other criteria are described in greater detail in Attachment 1.

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P-90159 Page 3 May 22, 1990 Recently, PSC and the NRC have discussed the issue of " reversibility" of plant closure activities relative to 'the impact of the plant closure activities on any future efforts tc resume normal operations.

PSC does not-consider that the component' removal activities currently under consideration are irreversible with regard to any hypothetically assumed future FSV operation. The time and costs to replace any removed components with new equipment would represenir, a small portion of the-time and costs involved with resuming plant operation. . Resolution of the known technical problems at FSV would require at: least five years, as identified i n_ . Reference 2.

Notwithstanding the. uncertainties associated with the resolution of several major generic technical problems, the unfavorable economic realities < associated with Fort St. Vrain's historical 15 percent

. capacity factor would still remain. PSC has permanently shut :down Fort St. Vrain and future plant operation is not an option under

-consideration.

PSC intends to initiate the plant-closure activities that are within our authority by June 22, 1990. If you have any questions regarding this request,' please respond by June 22, 1990 to Mr. M. H. Holmes at (303) 480-6960.

Very truly yours, (ibh A. C. Crawford Vice President Nuclear Operations ACC/SWC/km Attachments cc: Regional Administrator, Region IV ATTN: Mr. J. B. Baird Technical Assistant Division of. Reactor Projects Mr. Robert Farrell Senior Resident inspector Fort St. Vrain

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y- 3 P-90159 Page'3 May 22, 1990-

-Recently,- PSC and the NRC have discussed the issue of " reversibility" of plant closure activities relative to the impact of the plant closure' activities on any future efforts to resume norma 1' operations.

PSC does-not' consider that the component removal activities currently.

under- consideration are irreversible with regard to any-hypothetically assumed future FSV operation. The time and costs to replace. any- removed components with new equipment would represent a small portion of the-time and costs involved with resuming plant operation. Resolution of the known technical. problems;at FSV would-require at least five years, as identified in Reference. 2.

Notwithstanding the ' uncertainties associated with the resolution of.

several major generic technical problems, the unfavorable economic; realities associated with Fort St. Vrain's' historical 15-percent capacity factor would still remain. PSC has permanently shut down Fort St. Vrain and future plant operation is not an option under consideration.

PSC intends to initiate the-plant closure activities that are within our authority by June 22, 1990. If you have any questions' regarding -

this request, please respond by June 22, 1990 to Mr. M. H. Holmes at (303) 480-6960.

Very truly yours,

/M M A. C. Crawford Loensing Review By: [#

Vice President Date: fd/ d Nuclear Operations ACC/SWC/km Attachments cc: Regional Administrator, Region IV ATTN: Mr. J. B. Baird -

. Technical Assistant Division of Reactor Projects Mr. Robert Farrell Senior Resident inspector Fort St. Vrain 1

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ATTACHMENT 1 To P-90159 i COMPONENT REMOVAL ACTIVITIES WITHIN EXISTING LICENSEE AUTHORITY a.

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To P-90159 Page 1 of 5 COMPONENT REMOVAL ACTIVITIES WITHIN EXISTING LICENSEE AUTHORITY This attachment describes the component removal' activities that PSC intends to undertake at Fort St. Vrain beginning in June. 1990. PSC 3 considers that these activities are technically justified and are within existing licensee regulatory tuthority. Each component removal activity will be evaluated to verify that it meets the L

following requirements:

1, The activity must not require a change to the FSV Technical Specifications nor involve an unreviewed safety question, as determined by. an evaluation in accordance with the 4 provisions of 10 CFR 50.59. -

2. The activity must not have an adverse environmental impact, in .that it must not disturb environs not previously disturbed during plant construction or operation.

3. The activity must not preclude any of the three reasonable decommissioning alternatives: SAFSTOR, DECON, or ENTOMB.

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4. The activity must' not involve any significant increase in the total radiation exposure-required-for decommissioning.

5. The activity must have independent utility, in that there must be 'a justifiable purpose for . accomplishing the component removal activity other than mere dismantlement. '

t LISTING OF PLANNED FSV COMPONENT REMOVAL ACTIVITIES

-1, Disposal of Spare Control Rod Drive and Orifice Assemblies (CRD0A)

There are presently seven spare CRDOAs in storage outside of the.

Prestressed Concrete Reactor. Vessel (PCRV),-in the Equipment Storage Wells. PSC ' intends to ship some or all of these spare CRD0As off-site fer disposal. These spare assemblies are not required by any regulation or requirement and, with the plant permanently shutdown, they serve no useful function under any planned or postulated condition. Disposal of these spare assemblies at -this time is planned to allow use of the Beatty, Nevada., disposal facility. This facility has announced that it will no longer be available beyond December 31, 1992.

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Attachment 1 To P-90159 Page 2 of 5 In the event that a CRDOA in a fueled region failed and had to be- ,

replaced, a replacement CRDOA could be obtained from a defueled  ;

region. . CRDOAs have been reinstalled in the refueling penetrations- I above-the'defueled regions, but they'. serve no reactivity control function.

2. Disposal of Region Constraint Devices  !

Region constraint devices (RCDs) interlock the tops of adjacent core columns to~ prevent temperature fluctuations during power operation.

They were not intended to provide structural restraint at low core ,

flow rates, and they serve no function during shutdown conditinns.

They' are not required by any. Technical Specification LCO -Technical Specification SR 5,2.26 requires inspection of'RCDs during refueling '

outages prior. to the start of subsequent plant operation, and therefore, this inspection is not applicable. PSC intends tc dispose of the RCDs to allow use of the Beatty, Nevada, disposal: site, 3, . Removal and Post Irradiation Examination' (PIE) of a Steam Generator Main Steam Ring Header and Bimetallic Weld Sample DOE has proposed these activities'to support technology transfer for the New. Production Reactor (NPR) MHTGR (Attachment 3). PSC found -

, numerous crack -indications in the main steam ring headers of eight out of twelve steam generator modules-and further analysis could be beneficial to DOE and the NPR MHTGR. . Also, the steam generator 4 bimetallic welds- are of interest to evaluate their inservice performance. -c

-The steam generators are not explicitly required during shutdown conditions by any applicable Technical Speci fication or other regulation. The steam generator modules of one primary coolant loop are needed to mai,ntain required core temperatures during defueling and other in-core maintenance activities, but this is an operational .

requirement rather than a core safety requirement and redundancy is '

not required. All six of the modules of the Loop I steam generator are out of service and removal of a ring header and bimetallic weld sample would have no impact on decay heat removal capability.

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o Attachment 11 To P-90159 Page 3 of 5 Removal of a ring header involves the isolation of connecting.

- subheader; tubes and outlet' steam piping. There are two bimetallic

welds in~ the steam generators that would be of interest to evaluate inservice performance, one inside the PCRV and one outside the PCRV.

Due to acccss considerations, PSC is presently planning to remove a weld' sample from the bimetallic weld that is external to the PCRV.-

PSC is also investigating the feasibility of examining the bimetallic weld inside the PCRV, and this activity may be discussed with'the NRC at a-future date.

4. Removal .and Post Irradiation Examination (PIE) of a Control-Rod Absorber String and Control. Rod Drive Mechanism DOE proposed this activity to support technology transfer for the NPR MHTGR (Attachment 3).

. To obtain an absorber string and control rod drive mechanism with representative flux history, it is desirable to examine-a control rod drive assembly currently installed in a fueled region. PSC is-planning to select an appropriate-control rod drive assembly from a fueled. region, exchange it with one of the operable spare control rod

-drive assemblies discussed in Item'1'above, and provide it for PIE.

5. Removal and Post Irradiation Examination (PIE) of High Temperature Helium Purification System Components DOE proposed this activity as part of technology. transfer for the NPR-MHTGR (Attachment 3). l

'The FSV helium purification system consists of two trains of equipnent which include both high and low temperature components.

Primary coolant activity level is substantially reduced and this system will function mainly to aid in moisture removal and to provide a flowpath for PCRV pressure control and depressurization. A single train is sufficient for these functions and PSC is considering the removal of the high temperature' filter absorber and other components from the train that is not required. Removal of these components [

will involve isolating them from primary coolant. These helium purification system components are not required by the Technical Specifications.

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Attachment 1 To P-90159 Page 3 of 5

6. Removal of Helium Circulators from the PCRV This activity is being undertaken to allow use of personnel who are knowledgeable and experienced with both the helium circulator and '

with the circulator handling eauipment. These are unique and  ;

specialized devices and PSC considers that the removal operation can be accomplished more efficiently with qualified, experienced personnel who are currently available. P$C it planning to remove the  ;

two Loop I circulators as part of the current work activities, as time and safety considerations permit. The two Loop Il circulators will be removed af ter all fuel is removed from the PCRV.

In accordance with the Defueling Safety Analysis Report (PSC letter, Crawford to Weiss, dated 8/16/89 (P-89287)), forced circulation of prima ry coolant is no longer required to ensure the integrity of any of FSV's fission product barriers. Forced circulation is needed to  :

maintain' required core conditions during defueling and other in-core maintenance activitics, but this is an operational requirement rather i than a core safety requirement, and redundancy in primary coolant '

loops is not required.

Consistent with the reduced forced circulation requirements, the Loop I primary coolant circulation system has been permanently . shutdown.

Removal of the two Loop I helium circulators will not impact PSC's ability to maintain required core conditions during shutdown and defueling conditions.

Removal of the helium circulators from the PCRV will be performed using similar procedures, methocology, and equipment to that used during past circulator removal outages. The PCRV has been depressurized to less than 1 psig for defueling, in accordance with LCO 4.7.1, and administrative controls have been established to limit PCRV pressure to less than 5 psig at all other times. Under these  ;

depressurized conditions, the helium circulator penetrations will be sealed during circulator removal operations with a special ball valva device that has been used during past circulator removals, and with an equivalent device at all other times.

PSC's primary objective with this activity is to remove the two Loop I helium circulators from the PCRV. In addition, PSC has a spare circulator which is not required by any regulation or requirement.

PSC intends to dispose of one of these three helium circulators at the Beatty, Nevada, disposal site prior to its scheduled closure.

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l Attachment 1 j To P-90159 Page 5 of 5 )

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Initially, PSC will retain four helium circulators on-site, although  :

we may pursue their disposal at some future date. The helium  ;

circulators' include prima ry: and secondary.PCRV penetration sealing  ;

features. Before disposal; of any of .these .four circulators is  !

undartaken, PSC will request NRC approval of a Technical  !

Specification .hange to dispense with redundant full pressure-rated i closures on PCRV penetrations. Primary and secondary PCRV  ;

. penetration closures are described in the Design Features section- of .

the FSV Technical Specifications. '! ,

Until the Design Features .section is revised, PSC will maintain primary 'and secondary closure materials on-site for all PCRV .;

penetrations. This practice is cor.;istent with past outage practices  !

and it will ensure PSC's capability of establishing rated PCRV  ;

conditions, with the exception of the degraded steam generator main  :

steam ringheaders which were previously de-rated because of material  !

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ATTACHMENT 2 To P-90159 i'

PLANT CLOSURE ACTIVITIES FOR WHICH NRC APPROVAL WILL BE REQUESTED l

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PLANT CLOSURE ACTIVITIES FOR WHICH NRC APPROVAL WILL BE REQUESTED t

i 4; This attachment describes those plant closure activities for which I PSC intends.to request NRC approval via separate correspondence. -

Generally,-lthese activities will require an amendment to the FSV 2C Technical Specifications. They are' described herein to identif, 1 je those types of plant closure activities that PSC intends'to undertake '

J in advance of an approved decommissioning plan.

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1. Removal of Control Rod Drive and Orifice Assemblies from Defueled Regions i This activity is being undertaken to allow disposal and burial of the  !

highly. activated parts of the CRDOAs,. prior to the closure of the

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h .Beatty, Nev,ada, disposal site,. scheduled for December 31, 1992.  !

The CRDOAs.'in defueled core regions serve no reactivity control I

-function because the defueling elements in these regions do not have +

channels tot ' receive either the control rods or reserve shutdown .I material. The' orifice assemblies provide flow control ~ capability, j however, PSC's preliminary scoping analysis has determined that flow through the remaining fueled regions will be sufficient after orifice -

assemblies have been ' removed from all defueled regions, so flow

-control-capability is not required in defueled regions. The primary '

l seal portions of the CRDOAs can be readily detached from the rest of i the-assembly and they, or 'an equivalent sealing device, will be o

reinstalled. .

t PSC, will keep sufficient: CRDOAs installed in defueled regions to' .

serve.as installed spares for the remaining fueled regions. .;

' Removal of the CR00As from defueled regions requires a change to the  ;

Design Features of the Technical Specifications and NRC approval is

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required. The Design Features state that 37 control rod pairs are  ;

installed in the PCRV and removal of CRDOAs would be inconsistent with this description.

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! Attachment 2 l-To P-90159 page 2 of 2 b' 2. Removal of' Metal-Clad Top Reflector Blocks from Defueled Regions This' activity is being undertaken to allow disposal and' burial of the-

j. activated metal-clad top reflector blocks, prior to the closure of the Beatty Nevada, disposal site.

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The metal-clad te ~>ctor blocks on top of the defueling_ elements in defueled regions ar6 not required -for - flow control or reactivity

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- control. They are -keyed together within each individual region so- ~1 o that_they do provide'some stability when. adjacent regions are being-L defueled. PSC is planning to . remove these metal-clad reflector L blocks from regions only if the adjacent core regions have also .been P

defueled and replaced with defueling elements.

Removal of. metal-clad top reflector blocks requires a change to the Design Features of the Technical Specifications and NRC approval is required.

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ATTACHMENT 3 To P-90159 APRIL 16, 1990 LETTER FROM THE DEPARTMENT OF ENERGY REGARDINGTECHNOLOGYTRANSFER(G-90084) i

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April 16,1990  :

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Mr. N.'L. trey  :

Technology Transfer Manager.  :'

Publie Service Campany of Colorade Suite 1000 .- ,

2430 West R$th Avenue ,

Denver. CO 80211-t

Dear W . trey:

l The Department' of Energy (00E) has identified the components at Fort St. Vrain i (FSV) lheclear Generating Station that may provide beneficial knowledge for the design, construction,-eperation and dec emissionins of the New Production *

.Reester (WR) Modular Nigh Temperature Gas. Cooled Reacter (10lTOR). The DOE. sponsored FSV Technology Tr4nsfer program Technical Herking troup (TIA),  : I has identified the fellowing coinponents which are proposed fee remeval from  :

FSV and follow up post irradiation examination (P!t).  :

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1. Primary Systes Plateout-Probe .

2. Steam Generator Main Steam Ring Header  !

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3. Steen Generator timetallic Wald samples

4. Centrol Red Absorber String

5. Centrol Red Drive Mechanism i

6. Fuel Test Elements t

7. High Temperature Helius Purification System Components ,

This is neither an all inclusive Itst of FSV. components that may be of "

interest to NPR. nor does it represent a commitment that all of these components will be examined. Sese itens may be deleted from this list and -

additional items any be added as the design of the NPR MNTGA progresses.

sfacerely,  !

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P. J Dirknaat. Acting [

u IhtL NPR Project Manager cc: J. R. I reten, FSV l

J. D. Nu ten. W.43 H. Zeile, (688 -

S. Franks, W.43 h

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