ML17317B119

Forwards Proposed Tech Spec Re Reactivity Control Sys Moderator Temp Coefficient

ML17317B119
Person / Time
Site:	Cook
Issue date:	04/23/1979
From:	Maloney G INDIANA MICHIGAN POWER CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
AEP:NRC:00161, AEP:NRC:161, NUDOCS 7904250335
Download: ML17317B119 (10)

Text

INDIANA II MICHIGAN POWER COMPANY P. O. BOX 18 BOWLING GREEN STATION NEW YORK, N. Y. 10004 April 23, 1979 AEP:NgC:00]61 Donald C. Cook Nuclear Plant Unit No. 1 Docket No. 50-315 License No.: DPR-58 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory ComIission Washington, D.C. 20555

Dear Mr. Denton:

Attachment 1 to this letter contains a proposed Technical Speci-fication change for Unit of the Donald C. Cook Nuclear Plant. We 1

are requesting the upper bound of the Moderator Temperature Coefficient (MTC) given in Specification 3.1.1.4a be changed from 0 x 10-4 5 k/k/OF to +0.5 x 10-4 6k/k/oF. This change would significantly enhance plant operational flexibility during power ascension maneuvers early in each cycle (during the first 1500 MWD/MTU). In fact, without this change, beginning of cycle power'scension would be considerably more difficult.

A plant transient analysis applicable to the Donald C. Cook Unit 1 was performed by Exxon Nuclear Company to assess the impact of the change.

The evaluation model employed was consistent with previously submitted and appr'oved methods as detailed in Exxon Report XN-76-35. The results contained in the report are used as base case data in assessing the pro-posed change. It may be noted that conservative multipliers (1.2 and 0.8) were applied to the reactivity coefficients in a fashion consistent with XN-76-35. An additional conservatism was employed in that full power transients were analyzed using a predicted hot zero power value of the MTC.

The transients identified for analysis were:

(1) Loss of load at beginning of cycle (BOC),

(2) Locked rotor at BOC, (3) Loss of reactor coolant flow at BOC, (4) Fast and slow uncontrolled rod withdrawals at BOC.

Mr. Harold R. Oenton AEP:NRC:00161 Attachment 2 to this letter contains five tables which list the bounding neutronic parameters, initial conditions, and transient re-sults. Tables 3 and 4 summarize the analysis results. The principal effect of the proposed change is to slightly r educe the thermal margin for non-rod withdrawal events. The loss of reactor flow event was not explicitly analyzed since the locked rotor results bound this type of transient. In, rod withdrawal events, although the positive MTC contributes to increased power, sufficient moderator and fuel thermal lag exists such that the clad heat flux is not significantly increased before reactor scram. The margin reductions themselves are small as is exemplified in Table 5. The MONBR for the most 'limiting transient (locked rotor) remains substantially greater than the plant technical specification basic limit (1.79 vs. 1.30).

Thus, all criteria of the previous plant transient analysis(XN-76-35),

are met and the proposed change does not impact on the aforementioned safety criteria limits. This Technical Specification change has been re-viewed by both the PNSRC and the required membership of the AEPSC NSORC in accordance with the appropriate provisions of our Technical Specifications.

The result of this review indicates that the subject Techncial Specification change will not adversely affect the health and safety of the public.

Your urgent attention to this matter is kindly requested.

This Technical Specification change dea'Is with a single safety issue which does not involve a significant hazard issue. Therefore, pursuant to 170.22 of 10 CFR 170, a check (dated April 18, 1979, No. 200421) in an amount of $ 4,000.00 has been forwarded under a separate cover.

Very

/

truly yours,

/ pl~

GPM:em ~',Vice President P, Maloney Sworn and subscribed to before me this ~~'ay of April, 1979 in New York County, New York ag7 Aa Notary Public h.A."i!iL'l t'u"bC "

B.~~Y HCTARY Jfa ci Maw York Qg !,naJ rn 4;aanr Cccnry Car!ilia." i'i-"c in r:r:~ York Cccnty cc.(Attach d)

Mr. Harold R. Denton AEP:NRC:00161 cc: R. C. Callen P. M. Steketee G. Charnoff R. 'Malsh R. J. Vollen R. H. Jurgensen

0. V. Shaller-Bridgman

ATTACHMENT 1 PROPOSED TECHNICAL SPECIFICATION CHANGE AEP;NRC:00161 DONALD C. COOK NUCLEAR PLANT UNIT 1

REACTIVITY CONTROL SYSTEMS MODERATOR TEt1PERATURE COEFFICIENT LIMITING CONDITION FOR OPERATION 3.1.1.4 The moderator temperature coefficient (MTC} shall be:

a. ~+5.0 x 10-5 Kk/k/oF, and

b. Less negative than -3.5 x 10 4 hk/k/oF at RATED THERMAL POWER APPLICABILITY: MODES 1 and 2*

I ACTION'ith the moderator temperature coefficient outside any one of the above limits, be in HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

DONALD C, COOK NUCLEAR PLANT UNIT 1

ATTACHMENT 2 PLANT TRANSIENT ANALYSIS DATA AND RESULTS AEP:NRC:00161 DONALD C. COOK NUCLEAR PLANT UNIT 1

~ ~

TABLE 1 BOUNDING NEUTRONIC PARAMETERS*

Parameter BOC EOC BOG** EOC**

Moderator temperature coefficient (pcm/oF)*** +5.0 -30.0 -3.0 -30.0 Moderator density coefficient (pcm/gm/cc) -4500.0 +27000 0.0 +500.0 Delayed neutron fraction(X) 0.61 0.51 0.61 , 0.51 Boron worth coefficient (big/ppm x "104) -1. 4 -0. 85 -1. 4 -0.8 Total rod worth (X) -3. 40 -5.15 -3.40 -5.15 Doppler coefficient (Zlg>/o" x 105) -1.6 -1.1 -1. 6 design conservative multipliers were applied in actual analyses XN-76-35 analysis values 5

pcm = 10

TABLE 2

SUMMARY

OF DESIGN INITIAL CONDITIONS**

Parameter Loss of Load Locked Rotor Core Power (Milt) 3315* 3315*

Core inlet temperature (oF) 540.5* 540.5*

Primary pressurizer pressure (psia) 2220* 2220*

Primary flow rate (ibm/hr) 135.6 x 10 135 6 x 106*

'I Steam generator dome pressure (psia) 760 760 Total steam flow rate (lb m/hr) 14.4 x 106 14.4 x 10 Feedwater enthalphy (BTU/lb m) 413.8 413.8 FZ 1. 51 1. 51 Fq 2.36 2.36 1.60 1.60 Active/Total core flow 0.955 0.955 5 Heat Generated in Fuel 97.5 97.5 Nominal + uncertainties

• • No change from XN-76-35

TABLE 3 TRANSIENT RESULTS Variable Loss of Load Locked Rotor Peak core power (MWT) 3680 3471 Peak primary pressure (psia) 2571 2252 Maximum primary/secondaryhp(psi) 1495 1471 Maximum coolant flow rate (ibm/hr) 133.7 x 10 102.6 x 10 I

MDNBR (XN-76-35 w/o rod bow) 2.43 1. 98 MDNBR (w/o rod bow) 2.31 1. 85 MDNBR (w rod bow) 2.14 1.79 TABLE 4

SUMMARY

OF ROD WITHDRAWAL RESULTS Reactivity Insertion Maximum Core Power MDNBR MW(t) Current Current sec Xii.";76-35 ~Anal sis XN-76-35 A~nal sis 8 x 10 4 4230 4255 2.24 2.24 2 x 10-5 3633 3656 2.15 2.15

TABLE 5 Chan es in MDNBR As A Function Of MTC Moderator Coefficient Q MDNBR*

(pcm/QF)

'3.0 +5.0 Locked Rotor MONBR 1.98 1.85 0.13 Loss of Load,MDNBR 2. 43 2.31 0.12

• hMDNBR = Reduction in MONBR due to positive MTC